UNIVERSITY OF NAIROBI

DESIGN OF A WATER SUPPLY SYSTEM IN ONGATA

RONGAI

By Joan Karimi Mwiti F16363672010

A project submitted as a partial fulfillment for the requirement for the

award of the degree of

BACHELOR OF SCIENCE IN CIVIL ENGINEERING

2015

Abstract

The purpose of this project was to design a water supply system for Ongata Rongai Ongata

Rongai is one of the fastest growing towns in Nairobirsquos Metropolitan area The water supply

system in the area therefore needs to be upgraded to meet the ever increasing demand from both

the domestic and industrial use

The report therefore outlines the steps taken to collect the data needed for the design which

includes use of questionnaires interviews and literature documents It goes a step ahead to show

how the data collected was analyzed to get the demand of the area The data collected also gave

an overview of water shortage in the area and the different ways in which water is utilized The

main trunk line from the Kiserian dam which is the source was then designed together with a

distribution network for only a portion of the area This was because the discharge from the

source was not adequate to meet the demand of the area The profiles of the designed pipelines

were then plotted

Page | ii

Dedication

I would like to dedicate this project to my parents especially my mum who tirelessly worked to

ensure I did my best in everything particularly in my education As Abigail Adams once said

ldquoLearning is not attained by chance it must be sought for with ardor and intelligencerdquo

Page | iii

Acknowledgements

I would like to express my very great appreciation to everyone who helped me out in my project

Without you all I would not have made it this far

Special thanks should be given to my supervisor Dr Z N Oonge for his tireless efforts in

teaching and guiding me throughout this period

My deep gratitude goes out to all the staff at the county government for devoting their time to

make sure I got the data I required Their efforts are much appreciated

Finally I wish to thank my family and friends for their support and encouragement throughout this

period May the Almighty bless you all abundantly

Page | iv

Table of contents

Abstract ii

Dedication iii

Acknowledgements iv

List of figuresviii

List of tablesx

Chapter One1

10 Introduction1

11 General1

12 Problem Statement2

13 The objective and scope of study3

Chapter Two4

20 LITERATURE REVIEW4

21 Water Occurrence and Hydrology4

22 Description of area5

23 Water sources8

24 Water Demand10

25 Population projections11

26 Water distribution14

Chapter Three30

30 METHODOLOGY30

31 Introduction30

32 Data collection methods30

33 Problems in collection of data32

34 Data analysis32

Chapter Four34

40 RESULTS AND DISCUSSION34

41 Questionnaire analysis34

42 Population data48

43 Water Demand54

Page | v

44 Pipe Network Design60

Chapter Five64

50 CONCLUSION AND RECOMMENDATION64

51 Considerations in design64

52 Community involvement64

53 Recommendations65

60 REFERENCES66

APPENDICES67

Appendix 1 HGL calculations68

Appendix 2 Moody chart70

Appendix 3 Standard pipes71

Appendix 4 Questionnaire sample72

Page | vi

List of figures

Figure 21 The hydrological cycle4

Figure 22 Branched and looped distribution system16

Figure 23 Fully interconnected pipes17

Figure 24 Overcrossing single pipes17

Figure 25 House connection18

Figure 26 Yard connection19

Figure 27 Public Standpipes20

Figure 28 Variation of domestic water demand during the day22

Figure 29 Design capacities for water supply system components23

Figure 41 Gender distribution35

Figure 42 Type of family35

Figure 43 Household size36

Figure 44 Monthly income36

Figure 45 Sources of water available in the area37

Figure 46 Utilized sources38

Figure 47 Time taken to fetch water38

Figure 48 Frequency of buying water39

Figure 49 Shortages39

Figure 410 Price of water per jerrican40

Figure 411 Frequency of water supply41

Figure 412 Sufficiency of supply41

Figure 413 River Mbagathi42

Figure 414 Adequacy of main source43

Figure 415 Availability of water throughout the year43

Figure 416 Taste44

Figure 417 Turbidity 44

Figure 418 Paying for water45

Figure 419 Monthly water payments45

Page | vii

Figure 420 Willingness to spend more on better quality46

Figure 421 Water utilization46

Figure 422 Rainwater Harvesting47

Figure 423 Drinking water47

Page | viii

Page | ix

List of tables

Table 41 Human population data49

Table 42 Population projection for the area50

Table 43 ECD schools population data50

Table 44 Public primary schools population data50

Table 45 Private primary schools population data51

Table 46 Secondary schools population data51

Table 47 Schools population projection for the area52

Table 48 Health centres data52

Table 49 Livestock population data53

Table 410 Livestock conversion data54

Table 411 Service type55

Table 412 Human population data according to service type55

Table 413 Water consumption rates55

Table 414 Water demand used in lpday57

Table 415 Water demand in m3day human population57

Table 416 Water demand in m3day institution population58

Table 417 Water demand in m3day health centres58

Table 418 Water demand in m3day livestock population59

Table 419 Summary of water demand in m3 day59

Table 420 Pipeline details63

Page | x

Chapter One

10 Introduction

11 General

Water sustains life It essential to man animals and plants and without water life on earth would

not exist One of the most basic human commodities is access to clean water A country or

community without access to clean and safe water good sanitation and hygiene facilities is one

without a future This will be mainly due to the fact that the people will not be able to prevent

water-borne diseases which are one of the leading causes of death of children under five years In

addition to that they will not be able to practice farming for their consumption as well as have

water for their animals

One of the Millennium Development Goals is to ensure that by 2015 the proportion of people in

the world without access to sustainable safe drinking water and basic sanitation is halved In

order to do this it is necessary to provide access to safe drinking water This can only be done

through design and construction of various water supplydistribution systems in the urban and

rural areas If this is not possible in the rural areas provision of water pans may be necessary

Water supply and sanitation in Kenya is characterised by low levels of access in particular in

urban slums and in rural areas as well as poor service quality in the form of intermittent water

supply Only 9 out of 55 water service providers in Kenya provide continuous water supply

According to the Joint Monitoring Programmersquos 2012 report access to safe water supplies

throughout Kenya is 59 and access to improved sanitation is 32 There is still an unmet need

in rural and urban areas for both water and sanitation In urban areas access to improved water

has steadily declined over time This is because of the rapid urban population growth In addition

to that the high percentage of inactive connections means that the actual coverage is less than

stated Kenya faces challenges in water provision with erratic weather patterns in the past few

years causing droughts and water shortages

Page | 1

Abstract

The purpose of this project was to design a water supply system for Ongata Rongai Ongata

Rongai is one of the fastest growing towns in Nairobirsquos Metropolitan area The water supply

system in the area therefore needs to be upgraded to meet the ever increasing demand from both

the domestic and industrial use

The report therefore outlines the steps taken to collect the data needed for the design which

includes use of questionnaires interviews and literature documents It goes a step ahead to show

how the data collected was analyzed to get the demand of the area The data collected also gave

an overview of water shortage in the area and the different ways in which water is utilized The

main trunk line from the Kiserian dam which is the source was then designed together with a

distribution network for only a portion of the area This was because the discharge from the

source was not adequate to meet the demand of the area The profiles of the designed pipelines

were then plotted

Page | ii

Dedication

I would like to dedicate this project to my parents especially my mum who tirelessly worked to

ensure I did my best in everything particularly in my education As Abigail Adams once said

ldquoLearning is not attained by chance it must be sought for with ardor and intelligencerdquo

Page | iii

Acknowledgements

I would like to express my very great appreciation to everyone who helped me out in my project

Without you all I would not have made it this far

Special thanks should be given to my supervisor Dr Z N Oonge for his tireless efforts in

teaching and guiding me throughout this period

My deep gratitude goes out to all the staff at the county government for devoting their time to

make sure I got the data I required Their efforts are much appreciated

Finally I wish to thank my family and friends for their support and encouragement throughout this

period May the Almighty bless you all abundantly

Page | iv

Table of contents

Abstract ii

Dedication iii

Acknowledgements iv

List of figuresviii

List of tablesx

Chapter One1

10 Introduction1

11 General1

12 Problem Statement2

13 The objective and scope of study3

Chapter Two4

20 LITERATURE REVIEW4

21 Water Occurrence and Hydrology4

22 Description of area5

23 Water sources8

24 Water Demand10

25 Population projections11

26 Water distribution14

Chapter Three30

30 METHODOLOGY30

31 Introduction30

32 Data collection methods30

33 Problems in collection of data32

34 Data analysis32

Chapter Four34

40 RESULTS AND DISCUSSION34

41 Questionnaire analysis34

42 Population data48

43 Water Demand54

Page | v

44 Pipe Network Design60

Chapter Five64

50 CONCLUSION AND RECOMMENDATION64

51 Considerations in design64

52 Community involvement64

53 Recommendations65

60 REFERENCES66

APPENDICES67

Appendix 1 HGL calculations68

Appendix 2 Moody chart70

Appendix 3 Standard pipes71

Appendix 4 Questionnaire sample72

Page | vi

List of figures

Figure 21 The hydrological cycle4

Figure 22 Branched and looped distribution system16

Figure 23 Fully interconnected pipes17

Figure 24 Overcrossing single pipes17

Figure 25 House connection18

Figure 26 Yard connection19

Figure 27 Public Standpipes20

Figure 28 Variation of domestic water demand during the day22

Figure 29 Design capacities for water supply system components23

Figure 41 Gender distribution35

Figure 42 Type of family35

Figure 43 Household size36

Figure 44 Monthly income36

Figure 45 Sources of water available in the area37

Figure 46 Utilized sources38

Figure 47 Time taken to fetch water38

Figure 48 Frequency of buying water39

Figure 49 Shortages39

Figure 410 Price of water per jerrican40

Figure 411 Frequency of water supply41

Figure 412 Sufficiency of supply41

Figure 413 River Mbagathi42

Figure 414 Adequacy of main source43

Figure 415 Availability of water throughout the year43

Figure 416 Taste44

Figure 417 Turbidity 44

Figure 418 Paying for water45

Figure 419 Monthly water payments45

Page | vii

Figure 420 Willingness to spend more on better quality46

Figure 421 Water utilization46

Figure 422 Rainwater Harvesting47

Figure 423 Drinking water47

Page | viii

Page | ix

List of tables

Table 41 Human population data49

Table 42 Population projection for the area50

Table 43 ECD schools population data50

Table 44 Public primary schools population data50

Table 45 Private primary schools population data51

Table 46 Secondary schools population data51

Table 47 Schools population projection for the area52

Table 48 Health centres data52

Table 49 Livestock population data53

Table 410 Livestock conversion data54

Table 411 Service type55

Table 412 Human population data according to service type55

Table 413 Water consumption rates55

Table 414 Water demand used in lpday57

Table 415 Water demand in m3day human population57

Table 416 Water demand in m3day institution population58

Table 417 Water demand in m3day health centres58

Table 418 Water demand in m3day livestock population59

Table 419 Summary of water demand in m3 day59

Table 420 Pipeline details63

Page | x

Chapter One

10 Introduction

11 General

Water sustains life It essential to man animals and plants and without water life on earth would

not exist One of the most basic human commodities is access to clean water A country or

community without access to clean and safe water good sanitation and hygiene facilities is one

without a future This will be mainly due to the fact that the people will not be able to prevent

water-borne diseases which are one of the leading causes of death of children under five years In

addition to that they will not be able to practice farming for their consumption as well as have

water for their animals

One of the Millennium Development Goals is to ensure that by 2015 the proportion of people in

the world without access to sustainable safe drinking water and basic sanitation is halved In

order to do this it is necessary to provide access to safe drinking water This can only be done

through design and construction of various water supplydistribution systems in the urban and

rural areas If this is not possible in the rural areas provision of water pans may be necessary

Water supply and sanitation in Kenya is characterised by low levels of access in particular in

urban slums and in rural areas as well as poor service quality in the form of intermittent water

supply Only 9 out of 55 water service providers in Kenya provide continuous water supply

According to the Joint Monitoring Programmersquos 2012 report access to safe water supplies

throughout Kenya is 59 and access to improved sanitation is 32 There is still an unmet need

in rural and urban areas for both water and sanitation In urban areas access to improved water

has steadily declined over time This is because of the rapid urban population growth In addition

to that the high percentage of inactive connections means that the actual coverage is less than

stated Kenya faces challenges in water provision with erratic weather patterns in the past few

years causing droughts and water shortages

Page | 1

Dedication

I would like to dedicate this project to my parents especially my mum who tirelessly worked to

ensure I did my best in everything particularly in my education As Abigail Adams once said

ldquoLearning is not attained by chance it must be sought for with ardor and intelligencerdquo

Page | iii

Acknowledgements

I would like to express my very great appreciation to everyone who helped me out in my project

Without you all I would not have made it this far

Special thanks should be given to my supervisor Dr Z N Oonge for his tireless efforts in

teaching and guiding me throughout this period

My deep gratitude goes out to all the staff at the county government for devoting their time to

make sure I got the data I required Their efforts are much appreciated

Finally I wish to thank my family and friends for their support and encouragement throughout this

period May the Almighty bless you all abundantly

Page | iv

Table of contents

Abstract ii

Dedication iii

Acknowledgements iv

List of figuresviii

List of tablesx

Chapter One1

10 Introduction1

11 General1

12 Problem Statement2

13 The objective and scope of study3

Chapter Two4

20 LITERATURE REVIEW4

21 Water Occurrence and Hydrology4

22 Description of area5

23 Water sources8

24 Water Demand10

25 Population projections11

26 Water distribution14

Chapter Three30

30 METHODOLOGY30

31 Introduction30

32 Data collection methods30

33 Problems in collection of data32

34 Data analysis32

Chapter Four34

40 RESULTS AND DISCUSSION34

41 Questionnaire analysis34

42 Population data48

43 Water Demand54

Page | v

44 Pipe Network Design60

Chapter Five64

50 CONCLUSION AND RECOMMENDATION64

51 Considerations in design64

52 Community involvement64

53 Recommendations65

60 REFERENCES66

APPENDICES67

Appendix 1 HGL calculations68

Appendix 2 Moody chart70

Appendix 3 Standard pipes71

Appendix 4 Questionnaire sample72

Page | vi

List of figures

Figure 21 The hydrological cycle4

Figure 22 Branched and looped distribution system16

Figure 23 Fully interconnected pipes17

Figure 24 Overcrossing single pipes17

Figure 25 House connection18

Figure 26 Yard connection19

Figure 27 Public Standpipes20

Figure 28 Variation of domestic water demand during the day22

Figure 29 Design capacities for water supply system components23

Figure 41 Gender distribution35

Figure 42 Type of family35

Figure 43 Household size36

Figure 44 Monthly income36

Figure 45 Sources of water available in the area37

Figure 46 Utilized sources38

Figure 47 Time taken to fetch water38

Figure 48 Frequency of buying water39

Figure 49 Shortages39

Figure 410 Price of water per jerrican40

Figure 411 Frequency of water supply41

Figure 412 Sufficiency of supply41

Figure 413 River Mbagathi42

Figure 414 Adequacy of main source43

Figure 415 Availability of water throughout the year43

Figure 416 Taste44

Figure 417 Turbidity 44

Figure 418 Paying for water45

Figure 419 Monthly water payments45

Page | vii

Figure 420 Willingness to spend more on better quality46

Figure 421 Water utilization46

Figure 422 Rainwater Harvesting47

Figure 423 Drinking water47

Page | viii

Page | ix

List of tables

Table 41 Human population data49

Table 42 Population projection for the area50

Table 43 ECD schools population data50

Table 44 Public primary schools population data50

Table 45 Private primary schools population data51

Table 46 Secondary schools population data51

Table 47 Schools population projection for the area52

Table 48 Health centres data52

Table 49 Livestock population data53

Table 410 Livestock conversion data54

Table 411 Service type55

Table 412 Human population data according to service type55

Table 413 Water consumption rates55

Table 414 Water demand used in lpday57

Table 415 Water demand in m3day human population57

Table 416 Water demand in m3day institution population58

Table 417 Water demand in m3day health centres58

Table 418 Water demand in m3day livestock population59

Table 419 Summary of water demand in m3 day59

Table 420 Pipeline details63

Page | x

Chapter One

10 Introduction

11 General

Water sustains life It essential to man animals and plants and without water life on earth would

not exist One of the most basic human commodities is access to clean water A country or

community without access to clean and safe water good sanitation and hygiene facilities is one

without a future This will be mainly due to the fact that the people will not be able to prevent

water-borne diseases which are one of the leading causes of death of children under five years In

addition to that they will not be able to practice farming for their consumption as well as have

water for their animals

One of the Millennium Development Goals is to ensure that by 2015 the proportion of people in

the world without access to sustainable safe drinking water and basic sanitation is halved In

order to do this it is necessary to provide access to safe drinking water This can only be done

through design and construction of various water supplydistribution systems in the urban and

rural areas If this is not possible in the rural areas provision of water pans may be necessary

Water supply and sanitation in Kenya is characterised by low levels of access in particular in

urban slums and in rural areas as well as poor service quality in the form of intermittent water

supply Only 9 out of 55 water service providers in Kenya provide continuous water supply

According to the Joint Monitoring Programmersquos 2012 report access to safe water supplies

throughout Kenya is 59 and access to improved sanitation is 32 There is still an unmet need

in rural and urban areas for both water and sanitation In urban areas access to improved water

has steadily declined over time This is because of the rapid urban population growth In addition

to that the high percentage of inactive connections means that the actual coverage is less than

stated Kenya faces challenges in water provision with erratic weather patterns in the past few

years causing droughts and water shortages

Page | 1

Acknowledgements

I would like to express my very great appreciation to everyone who helped me out in my project

Without you all I would not have made it this far

Special thanks should be given to my supervisor Dr Z N Oonge for his tireless efforts in

teaching and guiding me throughout this period

My deep gratitude goes out to all the staff at the county government for devoting their time to

make sure I got the data I required Their efforts are much appreciated

Finally I wish to thank my family and friends for their support and encouragement throughout this

period May the Almighty bless you all abundantly

Page | iv

Table of contents

Abstract ii

Dedication iii

Acknowledgements iv

List of figuresviii

List of tablesx

Chapter One1

10 Introduction1

11 General1

12 Problem Statement2

13 The objective and scope of study3

Chapter Two4

20 LITERATURE REVIEW4

21 Water Occurrence and Hydrology4

22 Description of area5

23 Water sources8

24 Water Demand10

25 Population projections11

26 Water distribution14

Chapter Three30

30 METHODOLOGY30

31 Introduction30

32 Data collection methods30

33 Problems in collection of data32

34 Data analysis32

Chapter Four34

40 RESULTS AND DISCUSSION34

41 Questionnaire analysis34

42 Population data48

43 Water Demand54

Page | v

44 Pipe Network Design60

Chapter Five64

50 CONCLUSION AND RECOMMENDATION64

51 Considerations in design64

52 Community involvement64

53 Recommendations65

60 REFERENCES66

APPENDICES67

Appendix 1 HGL calculations68

Appendix 2 Moody chart70

Appendix 3 Standard pipes71

Appendix 4 Questionnaire sample72

Page | vi

List of figures

Figure 21 The hydrological cycle4

Figure 22 Branched and looped distribution system16

Figure 23 Fully interconnected pipes17

Figure 24 Overcrossing single pipes17

Figure 25 House connection18

Figure 26 Yard connection19

Figure 27 Public Standpipes20

Figure 28 Variation of domestic water demand during the day22

Figure 29 Design capacities for water supply system components23

Figure 41 Gender distribution35

Figure 42 Type of family35

Figure 43 Household size36

Figure 44 Monthly income36

Figure 45 Sources of water available in the area37

Figure 46 Utilized sources38

Figure 47 Time taken to fetch water38

Figure 48 Frequency of buying water39

Figure 49 Shortages39

Figure 410 Price of water per jerrican40

Figure 411 Frequency of water supply41

Figure 412 Sufficiency of supply41

Figure 413 River Mbagathi42

Figure 414 Adequacy of main source43

Figure 415 Availability of water throughout the year43

Figure 416 Taste44

Figure 417 Turbidity 44

Figure 418 Paying for water45

Figure 419 Monthly water payments45

Page | vii

Figure 420 Willingness to spend more on better quality46

Figure 421 Water utilization46

Figure 422 Rainwater Harvesting47

Figure 423 Drinking water47

Page | viii

Page | ix

List of tables

Table 41 Human population data49

Table 42 Population projection for the area50

Table 43 ECD schools population data50

Table 44 Public primary schools population data50

Table 45 Private primary schools population data51

Table 46 Secondary schools population data51

Table 47 Schools population projection for the area52

Table 48 Health centres data52

Table 49 Livestock population data53

Table 410 Livestock conversion data54

Table 411 Service type55

Table 412 Human population data according to service type55

Table 413 Water consumption rates55

Table 414 Water demand used in lpday57

Table 415 Water demand in m3day human population57

Table 416 Water demand in m3day institution population58

Table 417 Water demand in m3day health centres58

Table 418 Water demand in m3day livestock population59

Table 419 Summary of water demand in m3 day59

Table 420 Pipeline details63

Page | x

Chapter One

10 Introduction

11 General

Water sustains life It essential to man animals and plants and without water life on earth would

not exist One of the most basic human commodities is access to clean water A country or

community without access to clean and safe water good sanitation and hygiene facilities is one

without a future This will be mainly due to the fact that the people will not be able to prevent

water-borne diseases which are one of the leading causes of death of children under five years In

addition to that they will not be able to practice farming for their consumption as well as have

water for their animals

One of the Millennium Development Goals is to ensure that by 2015 the proportion of people in

the world without access to sustainable safe drinking water and basic sanitation is halved In

order to do this it is necessary to provide access to safe drinking water This can only be done

through design and construction of various water supplydistribution systems in the urban and

rural areas If this is not possible in the rural areas provision of water pans may be necessary

Water supply and sanitation in Kenya is characterised by low levels of access in particular in

urban slums and in rural areas as well as poor service quality in the form of intermittent water

supply Only 9 out of 55 water service providers in Kenya provide continuous water supply

According to the Joint Monitoring Programmersquos 2012 report access to safe water supplies

throughout Kenya is 59 and access to improved sanitation is 32 There is still an unmet need

in rural and urban areas for both water and sanitation In urban areas access to improved water

has steadily declined over time This is because of the rapid urban population growth In addition

to that the high percentage of inactive connections means that the actual coverage is less than

stated Kenya faces challenges in water provision with erratic weather patterns in the past few

years causing droughts and water shortages

Page | 1

Table of contents

Abstract ii

Dedication iii

Acknowledgements iv

List of figuresviii

List of tablesx

Chapter One1

10 Introduction1

11 General1

12 Problem Statement2

13 The objective and scope of study3

Chapter Two4

20 LITERATURE REVIEW4

21 Water Occurrence and Hydrology4

22 Description of area5

23 Water sources8

24 Water Demand10

25 Population projections11

26 Water distribution14

Chapter Three30

30 METHODOLOGY30

31 Introduction30

32 Data collection methods30

33 Problems in collection of data32

34 Data analysis32

Chapter Four34

40 RESULTS AND DISCUSSION34

41 Questionnaire analysis34

42 Population data48

43 Water Demand54

Page | v

44 Pipe Network Design60

Chapter Five64

50 CONCLUSION AND RECOMMENDATION64

51 Considerations in design64

52 Community involvement64

53 Recommendations65

60 REFERENCES66

APPENDICES67

Appendix 1 HGL calculations68

Appendix 2 Moody chart70

Appendix 3 Standard pipes71

Appendix 4 Questionnaire sample72

Page | vi

List of figures

Figure 21 The hydrological cycle4

Figure 22 Branched and looped distribution system16

Figure 23 Fully interconnected pipes17

Figure 24 Overcrossing single pipes17

Figure 25 House connection18

Figure 26 Yard connection19

Figure 27 Public Standpipes20

Figure 28 Variation of domestic water demand during the day22

Figure 29 Design capacities for water supply system components23

Figure 41 Gender distribution35

Figure 42 Type of family35

Figure 43 Household size36

Figure 44 Monthly income36

Figure 45 Sources of water available in the area37

Figure 46 Utilized sources38

Figure 47 Time taken to fetch water38

Figure 48 Frequency of buying water39

Figure 49 Shortages39

Figure 410 Price of water per jerrican40

Figure 411 Frequency of water supply41

Figure 412 Sufficiency of supply41

Figure 413 River Mbagathi42

Figure 414 Adequacy of main source43

Figure 415 Availability of water throughout the year43

Figure 416 Taste44

Figure 417 Turbidity 44

Figure 418 Paying for water45

Figure 419 Monthly water payments45

Page | vii

Figure 420 Willingness to spend more on better quality46

Figure 421 Water utilization46

Figure 422 Rainwater Harvesting47

Figure 423 Drinking water47

Page | viii

Page | ix

List of tables

Table 41 Human population data49

Table 42 Population projection for the area50

Table 43 ECD schools population data50

Table 44 Public primary schools population data50

Table 45 Private primary schools population data51

Table 46 Secondary schools population data51

Table 47 Schools population projection for the area52

Table 48 Health centres data52

Table 49 Livestock population data53

Table 410 Livestock conversion data54

Table 411 Service type55

Table 412 Human population data according to service type55

Table 413 Water consumption rates55

Table 414 Water demand used in lpday57

Table 415 Water demand in m3day human population57

Table 416 Water demand in m3day institution population58

Table 417 Water demand in m3day health centres58

Table 418 Water demand in m3day livestock population59

Table 419 Summary of water demand in m3 day59

Table 420 Pipeline details63

Page | x

Chapter One

10 Introduction

11 General

Water sustains life It essential to man animals and plants and without water life on earth would

not exist One of the most basic human commodities is access to clean water A country or

community without access to clean and safe water good sanitation and hygiene facilities is one

without a future This will be mainly due to the fact that the people will not be able to prevent

water-borne diseases which are one of the leading causes of death of children under five years In

addition to that they will not be able to practice farming for their consumption as well as have

water for their animals

One of the Millennium Development Goals is to ensure that by 2015 the proportion of people in

the world without access to sustainable safe drinking water and basic sanitation is halved In

order to do this it is necessary to provide access to safe drinking water This can only be done

through design and construction of various water supplydistribution systems in the urban and

rural areas If this is not possible in the rural areas provision of water pans may be necessary

Water supply and sanitation in Kenya is characterised by low levels of access in particular in

urban slums and in rural areas as well as poor service quality in the form of intermittent water

supply Only 9 out of 55 water service providers in Kenya provide continuous water supply

According to the Joint Monitoring Programmersquos 2012 report access to safe water supplies

throughout Kenya is 59 and access to improved sanitation is 32 There is still an unmet need

in rural and urban areas for both water and sanitation In urban areas access to improved water

has steadily declined over time This is because of the rapid urban population growth In addition

to that the high percentage of inactive connections means that the actual coverage is less than

stated Kenya faces challenges in water provision with erratic weather patterns in the past few

years causing droughts and water shortages

Page | 1

44 Pipe Network Design60

Chapter Five64

50 CONCLUSION AND RECOMMENDATION64

51 Considerations in design64

52 Community involvement64

53 Recommendations65

60 REFERENCES66

APPENDICES67

Appendix 1 HGL calculations68

Appendix 2 Moody chart70

Appendix 3 Standard pipes71

Appendix 4 Questionnaire sample72

Page | vi

List of figures

Figure 21 The hydrological cycle4

Figure 22 Branched and looped distribution system16

Figure 23 Fully interconnected pipes17

Figure 24 Overcrossing single pipes17

Figure 25 House connection18

Figure 26 Yard connection19

Figure 27 Public Standpipes20

Figure 28 Variation of domestic water demand during the day22

Figure 29 Design capacities for water supply system components23

Figure 41 Gender distribution35

Figure 42 Type of family35

Figure 43 Household size36

Figure 44 Monthly income36

Figure 45 Sources of water available in the area37

Figure 46 Utilized sources38

Figure 47 Time taken to fetch water38

Figure 48 Frequency of buying water39

Figure 49 Shortages39

Figure 410 Price of water per jerrican40

Figure 411 Frequency of water supply41

Figure 412 Sufficiency of supply41

Figure 413 River Mbagathi42

Figure 414 Adequacy of main source43

Figure 415 Availability of water throughout the year43

Figure 416 Taste44

Figure 417 Turbidity 44

Figure 418 Paying for water45

Figure 419 Monthly water payments45

Page | vii

Figure 420 Willingness to spend more on better quality46

Figure 421 Water utilization46

Figure 422 Rainwater Harvesting47

Figure 423 Drinking water47

Page | viii

Page | ix

List of tables

Table 41 Human population data49

Table 42 Population projection for the area50

Table 43 ECD schools population data50

Table 44 Public primary schools population data50

Table 45 Private primary schools population data51

Table 46 Secondary schools population data51

Table 47 Schools population projection for the area52

Table 48 Health centres data52

Table 49 Livestock population data53

Table 410 Livestock conversion data54

Table 411 Service type55

Table 412 Human population data according to service type55

Table 413 Water consumption rates55

Table 414 Water demand used in lpday57

Table 415 Water demand in m3day human population57

Table 416 Water demand in m3day institution population58

Table 417 Water demand in m3day health centres58

Table 418 Water demand in m3day livestock population59

Table 419 Summary of water demand in m3 day59

Table 420 Pipeline details63

Page | x

Chapter One

10 Introduction

11 General

Water sustains life It essential to man animals and plants and without water life on earth would

not exist One of the most basic human commodities is access to clean water A country or

community without access to clean and safe water good sanitation and hygiene facilities is one

without a future This will be mainly due to the fact that the people will not be able to prevent

water-borne diseases which are one of the leading causes of death of children under five years In

addition to that they will not be able to practice farming for their consumption as well as have

water for their animals

One of the Millennium Development Goals is to ensure that by 2015 the proportion of people in

the world without access to sustainable safe drinking water and basic sanitation is halved In

order to do this it is necessary to provide access to safe drinking water This can only be done

through design and construction of various water supplydistribution systems in the urban and

rural areas If this is not possible in the rural areas provision of water pans may be necessary

Water supply and sanitation in Kenya is characterised by low levels of access in particular in

urban slums and in rural areas as well as poor service quality in the form of intermittent water

supply Only 9 out of 55 water service providers in Kenya provide continuous water supply

According to the Joint Monitoring Programmersquos 2012 report access to safe water supplies

throughout Kenya is 59 and access to improved sanitation is 32 There is still an unmet need

in rural and urban areas for both water and sanitation In urban areas access to improved water

has steadily declined over time This is because of the rapid urban population growth In addition

to that the high percentage of inactive connections means that the actual coverage is less than

stated Kenya faces challenges in water provision with erratic weather patterns in the past few

years causing droughts and water shortages

Page | 1

List of figures

Figure 21 The hydrological cycle4

Figure 22 Branched and looped distribution system16

Figure 23 Fully interconnected pipes17

Figure 24 Overcrossing single pipes17

Figure 25 House connection18

Figure 26 Yard connection19

Figure 27 Public Standpipes20

Figure 28 Variation of domestic water demand during the day22

Figure 29 Design capacities for water supply system components23

Figure 41 Gender distribution35

Figure 42 Type of family35

Figure 43 Household size36

Figure 44 Monthly income36

Figure 45 Sources of water available in the area37

Figure 46 Utilized sources38

Figure 47 Time taken to fetch water38

Figure 48 Frequency of buying water39

Figure 49 Shortages39

Figure 410 Price of water per jerrican40

Figure 411 Frequency of water supply41

Figure 412 Sufficiency of supply41

Figure 413 River Mbagathi42

Figure 414 Adequacy of main source43

Figure 415 Availability of water throughout the year43

Figure 416 Taste44

Figure 417 Turbidity 44

Figure 418 Paying for water45

Figure 419 Monthly water payments45

Page | vii

Figure 420 Willingness to spend more on better quality46

Figure 421 Water utilization46

Figure 422 Rainwater Harvesting47

Figure 423 Drinking water47

Page | viii

Page | ix

List of tables

Table 41 Human population data49

Table 42 Population projection for the area50

Table 43 ECD schools population data50

Table 44 Public primary schools population data50

Table 45 Private primary schools population data51

Table 46 Secondary schools population data51

Table 47 Schools population projection for the area52

Table 48 Health centres data52

Table 49 Livestock population data53

Table 410 Livestock conversion data54

Table 411 Service type55

Table 412 Human population data according to service type55

Table 413 Water consumption rates55

Table 414 Water demand used in lpday57

Table 415 Water demand in m3day human population57

Table 416 Water demand in m3day institution population58

Table 417 Water demand in m3day health centres58

Table 418 Water demand in m3day livestock population59

Table 419 Summary of water demand in m3 day59

Table 420 Pipeline details63

Page | x

Chapter One

10 Introduction

11 General

Water sustains life It essential to man animals and plants and without water life on earth would

not exist One of the most basic human commodities is access to clean water A country or

community without access to clean and safe water good sanitation and hygiene facilities is one

without a future This will be mainly due to the fact that the people will not be able to prevent

water-borne diseases which are one of the leading causes of death of children under five years In

addition to that they will not be able to practice farming for their consumption as well as have

water for their animals

One of the Millennium Development Goals is to ensure that by 2015 the proportion of people in

the world without access to sustainable safe drinking water and basic sanitation is halved In

order to do this it is necessary to provide access to safe drinking water This can only be done

through design and construction of various water supplydistribution systems in the urban and

rural areas If this is not possible in the rural areas provision of water pans may be necessary

Water supply and sanitation in Kenya is characterised by low levels of access in particular in

urban slums and in rural areas as well as poor service quality in the form of intermittent water

supply Only 9 out of 55 water service providers in Kenya provide continuous water supply

According to the Joint Monitoring Programmersquos 2012 report access to safe water supplies

throughout Kenya is 59 and access to improved sanitation is 32 There is still an unmet need

in rural and urban areas for both water and sanitation In urban areas access to improved water

has steadily declined over time This is because of the rapid urban population growth In addition

to that the high percentage of inactive connections means that the actual coverage is less than

stated Kenya faces challenges in water provision with erratic weather patterns in the past few

years causing droughts and water shortages

Page | 1

Figure 420 Willingness to spend more on better quality46

Figure 421 Water utilization46

Figure 422 Rainwater Harvesting47

Figure 423 Drinking water47

Page | viii

Page | ix

List of tables

Table 41 Human population data49

Table 42 Population projection for the area50

Table 43 ECD schools population data50

Table 44 Public primary schools population data50

Table 45 Private primary schools population data51

Table 46 Secondary schools population data51

Table 47 Schools population projection for the area52

Table 48 Health centres data52

Table 49 Livestock population data53

Table 410 Livestock conversion data54

Table 411 Service type55

Table 412 Human population data according to service type55

Table 413 Water consumption rates55

Table 414 Water demand used in lpday57

Table 415 Water demand in m3day human population57

Table 416 Water demand in m3day institution population58

Table 417 Water demand in m3day health centres58

Table 418 Water demand in m3day livestock population59

Table 419 Summary of water demand in m3 day59

Table 420 Pipeline details63

Page | x

Chapter One

10 Introduction

11 General

Water sustains life It essential to man animals and plants and without water life on earth would

not exist One of the most basic human commodities is access to clean water A country or

community without access to clean and safe water good sanitation and hygiene facilities is one

without a future This will be mainly due to the fact that the people will not be able to prevent

water-borne diseases which are one of the leading causes of death of children under five years In

addition to that they will not be able to practice farming for their consumption as well as have

water for their animals

One of the Millennium Development Goals is to ensure that by 2015 the proportion of people in

the world without access to sustainable safe drinking water and basic sanitation is halved In

order to do this it is necessary to provide access to safe drinking water This can only be done

through design and construction of various water supplydistribution systems in the urban and

rural areas If this is not possible in the rural areas provision of water pans may be necessary

Water supply and sanitation in Kenya is characterised by low levels of access in particular in

urban slums and in rural areas as well as poor service quality in the form of intermittent water

supply Only 9 out of 55 water service providers in Kenya provide continuous water supply

According to the Joint Monitoring Programmersquos 2012 report access to safe water supplies

throughout Kenya is 59 and access to improved sanitation is 32 There is still an unmet need

in rural and urban areas for both water and sanitation In urban areas access to improved water

has steadily declined over time This is because of the rapid urban population growth In addition

to that the high percentage of inactive connections means that the actual coverage is less than

stated Kenya faces challenges in water provision with erratic weather patterns in the past few

years causing droughts and water shortages

Page | 1

Page | ix

List of tables

Table 41 Human population data49

Table 42 Population projection for the area50

Table 43 ECD schools population data50

Table 44 Public primary schools population data50

Table 45 Private primary schools population data51

Table 46 Secondary schools population data51

Table 47 Schools population projection for the area52

Table 48 Health centres data52

Table 49 Livestock population data53

Table 410 Livestock conversion data54

Table 411 Service type55

Table 412 Human population data according to service type55

Table 413 Water consumption rates55

Table 414 Water demand used in lpday57

Table 415 Water demand in m3day human population57

Table 416 Water demand in m3day institution population58

Table 417 Water demand in m3day health centres58

Table 418 Water demand in m3day livestock population59

Table 419 Summary of water demand in m3 day59

Table 420 Pipeline details63

Page | x

Chapter One

10 Introduction

11 General

Water sustains life It essential to man animals and plants and without water life on earth would

not exist One of the most basic human commodities is access to clean water A country or

community without access to clean and safe water good sanitation and hygiene facilities is one

without a future This will be mainly due to the fact that the people will not be able to prevent

water-borne diseases which are one of the leading causes of death of children under five years In

addition to that they will not be able to practice farming for their consumption as well as have

water for their animals

One of the Millennium Development Goals is to ensure that by 2015 the proportion of people in

the world without access to sustainable safe drinking water and basic sanitation is halved In

order to do this it is necessary to provide access to safe drinking water This can only be done

through design and construction of various water supplydistribution systems in the urban and

rural areas If this is not possible in the rural areas provision of water pans may be necessary

Water supply and sanitation in Kenya is characterised by low levels of access in particular in

urban slums and in rural areas as well as poor service quality in the form of intermittent water

supply Only 9 out of 55 water service providers in Kenya provide continuous water supply

According to the Joint Monitoring Programmersquos 2012 report access to safe water supplies

throughout Kenya is 59 and access to improved sanitation is 32 There is still an unmet need

in rural and urban areas for both water and sanitation In urban areas access to improved water

has steadily declined over time This is because of the rapid urban population growth In addition

to that the high percentage of inactive connections means that the actual coverage is less than

stated Kenya faces challenges in water provision with erratic weather patterns in the past few

years causing droughts and water shortages

Page | 1

List of tables

Table 41 Human population data49

Table 42 Population projection for the area50

Table 43 ECD schools population data50

Table 44 Public primary schools population data50

Table 45 Private primary schools population data51

Table 46 Secondary schools population data51

Table 47 Schools population projection for the area52

Table 48 Health centres data52

Table 49 Livestock population data53

Table 410 Livestock conversion data54

Table 411 Service type55

Table 412 Human population data according to service type55

Table 413 Water consumption rates55

Table 414 Water demand used in lpday57

Table 415 Water demand in m3day human population57

Table 416 Water demand in m3day institution population58

Table 417 Water demand in m3day health centres58

Table 418 Water demand in m3day livestock population59

Table 419 Summary of water demand in m3 day59

Table 420 Pipeline details63

Page | x

Chapter One

10 Introduction

11 General

Water sustains life It essential to man animals and plants and without water life on earth would

not exist One of the most basic human commodities is access to clean water A country or

community without access to clean and safe water good sanitation and hygiene facilities is one

without a future This will be mainly due to the fact that the people will not be able to prevent

water-borne diseases which are one of the leading causes of death of children under five years In

addition to that they will not be able to practice farming for their consumption as well as have

water for their animals

One of the Millennium Development Goals is to ensure that by 2015 the proportion of people in

the world without access to sustainable safe drinking water and basic sanitation is halved In

order to do this it is necessary to provide access to safe drinking water This can only be done

through design and construction of various water supplydistribution systems in the urban and

rural areas If this is not possible in the rural areas provision of water pans may be necessary

Water supply and sanitation in Kenya is characterised by low levels of access in particular in

urban slums and in rural areas as well as poor service quality in the form of intermittent water

supply Only 9 out of 55 water service providers in Kenya provide continuous water supply

According to the Joint Monitoring Programmersquos 2012 report access to safe water supplies

throughout Kenya is 59 and access to improved sanitation is 32 There is still an unmet need

in rural and urban areas for both water and sanitation In urban areas access to improved water

has steadily declined over time This is because of the rapid urban population growth In addition

to that the high percentage of inactive connections means that the actual coverage is less than

stated Kenya faces challenges in water provision with erratic weather patterns in the past few

years causing droughts and water shortages

Page | 1

Chapter One

10 Introduction

11 General

Water sustains life It essential to man animals and plants and without water life on earth would

not exist One of the most basic human commodities is access to clean water A country or

community without access to clean and safe water good sanitation and hygiene facilities is one

without a future This will be mainly due to the fact that the people will not be able to prevent

water-borne diseases which are one of the leading causes of death of children under five years In

addition to that they will not be able to practice farming for their consumption as well as have

water for their animals

One of the Millennium Development Goals is to ensure that by 2015 the proportion of people in

the world without access to sustainable safe drinking water and basic sanitation is halved In

order to do this it is necessary to provide access to safe drinking water This can only be done

through design and construction of various water supplydistribution systems in the urban and

rural areas If this is not possible in the rural areas provision of water pans may be necessary

Water supply and sanitation in Kenya is characterised by low levels of access in particular in

urban slums and in rural areas as well as poor service quality in the form of intermittent water

supply Only 9 out of 55 water service providers in Kenya provide continuous water supply

According to the Joint Monitoring Programmersquos 2012 report access to safe water supplies

throughout Kenya is 59 and access to improved sanitation is 32 There is still an unmet need

in rural and urban areas for both water and sanitation In urban areas access to improved water

has steadily declined over time This is because of the rapid urban population growth In addition

to that the high percentage of inactive connections means that the actual coverage is less than

stated Kenya faces challenges in water provision with erratic weather patterns in the past few

years causing droughts and water shortages

Page | 1

Kenya also has a limited renewable water supply and is classified as a water scarce country

Urban migration contributes to challenges in sanitation as people crowd into cities and urban

growth is unregulated

The Ministry of Water and Irrigation remains the coordinator policy formulator and quality

controller for the water sector Under the Water Act 2002 an institutional setup was created as

follows Water Service Providers (WSPs) are linked to 8 regional Water Services Boards

(WSBs) in charge of asset management through Service Provision Agreements (SPAs) The Act

also created a national regulatory board Water Services Regulatory Board (WSRB) that carries

out performance benchmarking and is in charge of approving SPAs and tariff adjustments

Ongata Rongai is under the Tanathi Water Services Board Oloolaiser Water and Sewerage

Company is the Water Service Provider located in the town and it is responsible for supplying

water from the recently completed Kiserian dam among other sources that they utilise

12 Problem Statement

Ongata Rongai is one of the fastest growing towns in Nairobirsquos Metropolitan area It was

originally occupied by the Maasai Since it was a rural area in the 1980rsquos and early 1990rsquos it was

not planned The transport water supply and sewerage aspects of the town were not considered

at that time However over the past fifteen years Ongata Rongai has grown immensely in

population This has brought up the need for better infrastructure and social amenities like

schools hospitals and market centres to cater for the large population

This alone is not adequate the water supply in the area needs to be upgraded to meet the ever

increasing demand from both the domestic and industrial use The area is currently supplied with

water from boreholes from small-scale WSPs This presents another challenge because the

underground water in the area is hard and most of the water is not adequately treated to the

required WHO drinking water standards The water from the boreholes from recent studies is

found to contain high amounts of iron which is in excess of the recommended Drinking Water

Quality Standards for Kenya This poses as a health risk to the users There was therefore need to

source out another water source that would be reliable and provide safe water for consumption

Page | 2

This need lead to the construction of the Kiserian dam The project included the construction of a

dam on the Kiserian River raw water mains treatment works and storage tanks The dam was

designed to meet the current water demand for the surrounding towns which are Ngong

Kiserian Kajiado and Ongata Rongai

The water from the dam is treated to the required standards before it is supplied This solves the

problem of inadequate water quality standards It is also necessary to provide a means of

distribution of the water from the dam hence the need for design of a water supply system

13 The objective and scope of study

Main Objective

The objective of this project is to design a water distribution system that will supply safe

drinking water that will meet the demand of people in the area

Specific Objectives

To achieve this objective the following studies will be done

Find out the water utilization in the area

Find gaps in demand and recommend other alternative sources of water to fill the gaps

Find out the current supply from the dam

Page | 3

Chapter Two

20 LITERATURE REVIEW

21 Water Occurrence and Hydrology

The first step in designing a water supply system is to select a suitable source or a combination

of sources of water The source must be capable of supplying enough water for the community

If not perhaps another source or several sources will be required

The water on earth whether as water vapour in the atmosphere as surface water in rivers

streams lakes seas and oceans or as ground water in sub surface ground strata is for the most

part not at rest but in a state of continuous recycling movement This is called the hydrological

cycle (E H Hofkes et al 1981)

Figure 21 The hydrological cycle (Ingles II 2013)

Page | 4

By far the greatest part of the water on earth is found in the oceans and seas However this water

is saline The amount of fresh water is less than 3 about two thirds of which is locked up in ice

caps and glaciers The fresh water contained in the underground and in all lakes rivers streams

brooks pools and swamps amount to less than 1 of the worldrsquos water stock

Information regarding the amount of rainfall the flow of rivers and streams the quantity and

depth of groundwater and evaporation is needed by the engineer This information is rarely

available so that it will be necessary to take field measurements or extrapolate data from such

records as available (E H Hofkes et al 1981)

22 Description of area

221 LocationOngata Rongai is situated 17 km south of central business district of Nairobi city the capital city

of Kenya It is one of the locations in Ngong Division Kajiado District Its coordinates are

approximately 20 45rsquorsquo 00rsquo S and 370 23rsquorsquo 00rsquo E

The physical boundaries of the town are Kandisi River to the South and Mbagathi River to the

North The town can be accessed through the Nairobi-Magadi road It covers an area of about

165 Km2 The townrsquos administrative boundaries have changed over years and it covers a much

larger area with its ever increasing population This could be attributed to its proximity to

Nairobi and its cost of living compared to the capital city

222 ClimateThe largest part of Kajiado is semi-arid The mean annual rainfall ranges from 300 to 800 mm

Rainfall is bimodal with short rains from October to December and long rains from March

to May The distribution of rainfall between the two seasons changes gradually from east to west

across Kajiado District In eastern Kajiado more rain falls during the short rains than during the

long rains In western Kajiado the majority of rain falls during the long rains Heavy rains

occur around Ngong Hills Chyulu Hills Nguruman escarpment and the foothills of Mt

Kilimanjaro This is because the rainfall in the district is strongly influenced by altitude

The temperatures in the district also vary according to altitude Mean maximum of 34ordmC around

L Magadi and a mean minimum of 10ordmC on the foothills of Kilimanjaro have been recorded

Page | 5

Moisture deficit is also observed in the greater part of the year This gives the district a dry

season of between 7-9 months

As for the region around Ongata Rongai the climate is warm and temperate There is significant

rainfall throughout the year in Ongata Rongai The average annual temperature in Ongata Rongai

is 183 degC About 844 mm of precipitation falls annually

223 Topography and GeologyThe main physical features in the district are plains and occasional hills and valleys Several

valleys dissect the plains and its physiography is influenced by geology The land rises from

500m asl around L Magadi to 2500m asl in the Ngong hills area Ongata Rongai lies at

approximately 1731m asl The area slopes as you move towards Ongata Rongai town from

Kiserian and Ngong

The ground surface represents eroded remnants of a former volcanic or string of volcanoes that

previously measured over eleven kilometres in diameter The area is covered mainly by black

cotton soils which is essentially not suitable for farming (Kajiado District Environment Action

Plan 2009-2013)

224 Socio-economic Infrastructure

2241 AdministrationOngata Rongai is one of the locations in Ngong Division It covers Ongata Rongai and Ole

Kasasi sub-locations It is under Kajiado north constituency and Kajiado County It has one of

the highest population growth rates with its population increasing after every census since 2009

2242 EducationOngata Rongai has many schools distributed within the area most of them being primary schools

Most of them are private The area basically has a shortage of public schools There are two main

universities which are within the area namely Africa Nazarene University and Adventist

University of Africa Catholic University of East Africa is also located a few kilometers from the

town itself There are also quite a number of ECD schools and high schools in the area (Kajiado

District Environment Action Plan 2009-2013)

Page | 6

2243 Health FacilitiesOngata Rongai has a number of health facilities most of them being clinics They are both

private and public namely Garlands Aga Khan Kenyatta national hospital These are some of

the hospitals that have opened clinics in the town itself

2244 TransportIn Kajiado district the major roads tend to follow the north-south direction connecting to the

Nairobi-Mombasa road With Nairobi outside Kajiado as the focal point three major road

networks emerge to Magadi to Namanga through Athi River and Kajiado to Loitokitok through

Sultan Hamud and Emali on Mombasa road

The only tarmac roads in the whole district are the Nairobi to Namanga (153kms) Nairobi

Magadi roads which passes through Ongata RongaiKiserian or NgongKiserian (102kms) and

the Kiserian Isinya road The road which leads to the dam itself is an all-weather road Most of

the access roads are not tarmacked and some become impassable during the rainy season

There is a railway line passing through the area but it used to transport Soda ash from Magadi

People in the town also use motorbikes and bicycles to move around and also transport their

goods This is in addition to the donkeys and the carts which are also used (Kajiado District

Environment Action Plan 2009-2013)

2245 Commerce and IndustryThe area is growing at a very high rate This has created business opportunities in the area The

town currently has three large supermarkets These are all accompanied by hotels bars shops

and many more The town also has water vendors who use donkeys as their mode of transport

There are also two market centres in the area one located at Kware and the other known as Soko

mjinga The market day in the area is normally on Sundays

Quarrying is also another main economic activity of the area With new buildings springing up

every day it is one of the main income generating activities of people in the area especially the

ones who live in the low class housing of the area It also has an agro-processing industry located

in Gataka known as Tam-feeds (Kajiado District Environment Action Plan 2009-2013)

Page | 7

2246 AgricultureFarming in the area is practiced in small-scale because the area is highly populated leaving little

land to practice agriculture Most of the crops grown in the area include maize beans bananas

and vegetables Most of the Maasai who live in the area are pastoralists and they keep a large

number of livestock There is a slaughter house located in Kiserian and most of the pastoralists

sell their livestock at the slaughter house (Kajiado District Environment Action Plan 2009-2013

NEMA)

23 Water sources

Basically all sources of freshwater originate from rainfall which is slightly acidic due to

dissolution of carbon dioxide in the atmosphere In form of surface run off it will gather

considerable amounts of organic and mineral matters soil particles microorganisms etc When

surface runoff infiltrates into subsoil level it forms ground water As the ground level water

increases due to varying land formations it oozes out as springs Perennial springs are the

fountain heads of surface water bodies such as streams rivers and lakes

The source of water has a major effect on water system design and hence costs Water from

different sources vary in quality and hence requires varying degrees of treatment The process of

choosing the most suitable source of water supply largely depends on local conditions A source

of water supply can be identified at any of the above stages of water cycle provided it can supply

in sufficient quantities for most periods of the time in the year (Sundaravadivel S V 2007)

When a new water supply is required to meet anticipated increased demand it is common

practice to undertake an assessment of the water resources of the region to consider all possible

sources of supply and then to define an appropriate development plan The range of development

possibilities are as follows

231 Ground water sourcesThese are the sources that tap their water from ground aquifers in the underground rocks or

strata The aquifers are water yielding rocks normally in between two impervious rocks or an

impervious and pervious rock The aquifers are actually water reservoirs which retain water that

has trickled through the pervious or impervious rocks formation commonly termed as water

table

Page | 8

Water tables that are formed in between impervious rocks are in most cases deep and are

permanent water sources while those that form between pervious and impervious rocks are

shallow and are seasonal water suppliers The ground water sources include

Springs

Springs are naturally occurring water source that emerge from the ground They mainly occur in

hilly mountainous areas and river valleys There are mainly two types of springs

a) Gravity springs Occur where ground water emerges at the surface because an impervious

layer prevents it from seeping downwards This happened when an unconfined aquifer emerges

into the open It occurs on sloping ground The flow depends on the water table

b) Artesian springs Occurs where ground water emerges at the surface after confinement The

flow is very nearly constant

Wells

Water well is an excavation created in the ground to access water in the aquifers They greatly

vary in depth depending on the water table The diameter of such excavations determines

whether it is a borehole or a well wells have larger diameters than boreholes It can be excavated

by digging driving boring or drilling to the water table The wells can either be

a) Shallow wells Manual digging can be used to excavate wells to reach the aquifer Their

diameters are large enough to accommodate well diggers with their tools They can be dug up to

a depth of 20-30m usually in loose soils by hand

b) Deep wells These are normally excavated by drilling or by driving methods The depth

normally ranges from 6 -180m deep depending on the level of the water table

232 Surface water sourcesSurface water supply is the water from the lakes reservoirs rivers and streams These water

bodies are formed of water from direct rain runoffs and springs A runoff is the part of rain

water that does not infiltrate the ground or evaporate It flows by gravity into the water body

from the surrounding land The total land area that contributes surface runoff to a river or lake is

called a watershed drainage basin or catchment area

Page | 9

Chapter Two

20 LITERATURE REVIEW

21 Water Occurrence and Hydrology

The first step in designing a water supply system is to select a suitable source or a combination

of sources of water The source must be capable of supplying enough water for the community

If not perhaps another source or several sources will be required

The water on earth whether as water vapour in the atmosphere as surface water in rivers

streams lakes seas and oceans or as ground water in sub surface ground strata is for the most

part not at rest but in a state of continuous recycling movement This is called the hydrological

cycle (E H Hofkes et al 1981)

Figure 21 The hydrological cycle (Ingles II 2013)

Page | 4

By far the greatest part of the water on earth is found in the oceans and seas However this water

is saline The amount of fresh water is less than 3 about two thirds of which is locked up in ice

caps and glaciers The fresh water contained in the underground and in all lakes rivers streams

brooks pools and swamps amount to less than 1 of the worldrsquos water stock

Information regarding the amount of rainfall the flow of rivers and streams the quantity and

depth of groundwater and evaporation is needed by the engineer This information is rarely

available so that it will be necessary to take field measurements or extrapolate data from such

records as available (E H Hofkes et al 1981)

22 Description of area

221 LocationOngata Rongai is situated 17 km south of central business district of Nairobi city the capital city

of Kenya It is one of the locations in Ngong Division Kajiado District Its coordinates are

approximately 20 45rsquorsquo 00rsquo S and 370 23rsquorsquo 00rsquo E

The physical boundaries of the town are Kandisi River to the South and Mbagathi River to the

North The town can be accessed through the Nairobi-Magadi road It covers an area of about

165 Km2 The townrsquos administrative boundaries have changed over years and it covers a much

larger area with its ever increasing population This could be attributed to its proximity to

Nairobi and its cost of living compared to the capital city

222 ClimateThe largest part of Kajiado is semi-arid The mean annual rainfall ranges from 300 to 800 mm

Rainfall is bimodal with short rains from October to December and long rains from March

to May The distribution of rainfall between the two seasons changes gradually from east to west

across Kajiado District In eastern Kajiado more rain falls during the short rains than during the

long rains In western Kajiado the majority of rain falls during the long rains Heavy rains

occur around Ngong Hills Chyulu Hills Nguruman escarpment and the foothills of Mt

Kilimanjaro This is because the rainfall in the district is strongly influenced by altitude

The temperatures in the district also vary according to altitude Mean maximum of 34ordmC around

L Magadi and a mean minimum of 10ordmC on the foothills of Kilimanjaro have been recorded

Page | 5

Moisture deficit is also observed in the greater part of the year This gives the district a dry

season of between 7-9 months

As for the region around Ongata Rongai the climate is warm and temperate There is significant

rainfall throughout the year in Ongata Rongai The average annual temperature in Ongata Rongai

is 183 degC About 844 mm of precipitation falls annually

223 Topography and GeologyThe main physical features in the district are plains and occasional hills and valleys Several

valleys dissect the plains and its physiography is influenced by geology The land rises from

500m asl around L Magadi to 2500m asl in the Ngong hills area Ongata Rongai lies at

approximately 1731m asl The area slopes as you move towards Ongata Rongai town from

Kiserian and Ngong

The ground surface represents eroded remnants of a former volcanic or string of volcanoes that

previously measured over eleven kilometres in diameter The area is covered mainly by black

cotton soils which is essentially not suitable for farming (Kajiado District Environment Action

Plan 2009-2013)

224 Socio-economic Infrastructure

2241 AdministrationOngata Rongai is one of the locations in Ngong Division It covers Ongata Rongai and Ole

Kasasi sub-locations It is under Kajiado north constituency and Kajiado County It has one of

the highest population growth rates with its population increasing after every census since 2009

2242 EducationOngata Rongai has many schools distributed within the area most of them being primary schools

Most of them are private The area basically has a shortage of public schools There are two main

universities which are within the area namely Africa Nazarene University and Adventist

University of Africa Catholic University of East Africa is also located a few kilometers from the

town itself There are also quite a number of ECD schools and high schools in the area (Kajiado

District Environment Action Plan 2009-2013)

Page | 6

2243 Health FacilitiesOngata Rongai has a number of health facilities most of them being clinics They are both

private and public namely Garlands Aga Khan Kenyatta national hospital These are some of

the hospitals that have opened clinics in the town itself

2244 TransportIn Kajiado district the major roads tend to follow the north-south direction connecting to the

Nairobi-Mombasa road With Nairobi outside Kajiado as the focal point three major road

networks emerge to Magadi to Namanga through Athi River and Kajiado to Loitokitok through

Sultan Hamud and Emali on Mombasa road

The only tarmac roads in the whole district are the Nairobi to Namanga (153kms) Nairobi

Magadi roads which passes through Ongata RongaiKiserian or NgongKiserian (102kms) and

the Kiserian Isinya road The road which leads to the dam itself is an all-weather road Most of

the access roads are not tarmacked and some become impassable during the rainy season

There is a railway line passing through the area but it used to transport Soda ash from Magadi

People in the town also use motorbikes and bicycles to move around and also transport their

goods This is in addition to the donkeys and the carts which are also used (Kajiado District

Environment Action Plan 2009-2013)

2245 Commerce and IndustryThe area is growing at a very high rate This has created business opportunities in the area The

town currently has three large supermarkets These are all accompanied by hotels bars shops

and many more The town also has water vendors who use donkeys as their mode of transport

There are also two market centres in the area one located at Kware and the other known as Soko

mjinga The market day in the area is normally on Sundays

Quarrying is also another main economic activity of the area With new buildings springing up

every day it is one of the main income generating activities of people in the area especially the

ones who live in the low class housing of the area It also has an agro-processing industry located

in Gataka known as Tam-feeds (Kajiado District Environment Action Plan 2009-2013)

Page | 7

2246 AgricultureFarming in the area is practiced in small-scale because the area is highly populated leaving little

land to practice agriculture Most of the crops grown in the area include maize beans bananas

and vegetables Most of the Maasai who live in the area are pastoralists and they keep a large

number of livestock There is a slaughter house located in Kiserian and most of the pastoralists

sell their livestock at the slaughter house (Kajiado District Environment Action Plan 2009-2013

NEMA)

23 Water sources

Basically all sources of freshwater originate from rainfall which is slightly acidic due to

dissolution of carbon dioxide in the atmosphere In form of surface run off it will gather

considerable amounts of organic and mineral matters soil particles microorganisms etc When

surface runoff infiltrates into subsoil level it forms ground water As the ground level water

increases due to varying land formations it oozes out as springs Perennial springs are the

fountain heads of surface water bodies such as streams rivers and lakes

The source of water has a major effect on water system design and hence costs Water from

different sources vary in quality and hence requires varying degrees of treatment The process of

choosing the most suitable source of water supply largely depends on local conditions A source

of water supply can be identified at any of the above stages of water cycle provided it can supply

in sufficient quantities for most periods of the time in the year (Sundaravadivel S V 2007)

When a new water supply is required to meet anticipated increased demand it is common

practice to undertake an assessment of the water resources of the region to consider all possible

sources of supply and then to define an appropriate development plan The range of development

possibilities are as follows

231 Ground water sourcesThese are the sources that tap their water from ground aquifers in the underground rocks or

strata The aquifers are water yielding rocks normally in between two impervious rocks or an

impervious and pervious rock The aquifers are actually water reservoirs which retain water that

has trickled through the pervious or impervious rocks formation commonly termed as water

table

Page | 8

Water tables that are formed in between impervious rocks are in most cases deep and are

permanent water sources while those that form between pervious and impervious rocks are

shallow and are seasonal water suppliers The ground water sources include

Springs

Springs are naturally occurring water source that emerge from the ground They mainly occur in

hilly mountainous areas and river valleys There are mainly two types of springs

a) Gravity springs Occur where ground water emerges at the surface because an impervious

layer prevents it from seeping downwards This happened when an unconfined aquifer emerges

into the open It occurs on sloping ground The flow depends on the water table

b) Artesian springs Occurs where ground water emerges at the surface after confinement The

flow is very nearly constant

Wells

Water well is an excavation created in the ground to access water in the aquifers They greatly

vary in depth depending on the water table The diameter of such excavations determines

whether it is a borehole or a well wells have larger diameters than boreholes It can be excavated

by digging driving boring or drilling to the water table The wells can either be

a) Shallow wells Manual digging can be used to excavate wells to reach the aquifer Their

diameters are large enough to accommodate well diggers with their tools They can be dug up to

a depth of 20-30m usually in loose soils by hand

b) Deep wells These are normally excavated by drilling or by driving methods The depth

normally ranges from 6 -180m deep depending on the level of the water table

232 Surface water sourcesSurface water supply is the water from the lakes reservoirs rivers and streams These water

bodies are formed of water from direct rain runoffs and springs A runoff is the part of rain

water that does not infiltrate the ground or evaporate It flows by gravity into the water body

from the surrounding land The total land area that contributes surface runoff to a river or lake is

called a watershed drainage basin or catchment area

Page | 9

By far the greatest part of the water on earth is found in the oceans and seas However this water

is saline The amount of fresh water is less than 3 about two thirds of which is locked up in ice

caps and glaciers The fresh water contained in the underground and in all lakes rivers streams

brooks pools and swamps amount to less than 1 of the worldrsquos water stock

Information regarding the amount of rainfall the flow of rivers and streams the quantity and

depth of groundwater and evaporation is needed by the engineer This information is rarely

available so that it will be necessary to take field measurements or extrapolate data from such

records as available (E H Hofkes et al 1981)

22 Description of area

221 LocationOngata Rongai is situated 17 km south of central business district of Nairobi city the capital city

of Kenya It is one of the locations in Ngong Division Kajiado District Its coordinates are

approximately 20 45rsquorsquo 00rsquo S and 370 23rsquorsquo 00rsquo E

The physical boundaries of the town are Kandisi River to the South and Mbagathi River to the

North The town can be accessed through the Nairobi-Magadi road It covers an area of about

165 Km2 The townrsquos administrative boundaries have changed over years and it covers a much

larger area with its ever increasing population This could be attributed to its proximity to

Nairobi and its cost of living compared to the capital city

222 ClimateThe largest part of Kajiado is semi-arid The mean annual rainfall ranges from 300 to 800 mm

Rainfall is bimodal with short rains from October to December and long rains from March

to May The distribution of rainfall between the two seasons changes gradually from east to west

across Kajiado District In eastern Kajiado more rain falls during the short rains than during the

long rains In western Kajiado the majority of rain falls during the long rains Heavy rains

occur around Ngong Hills Chyulu Hills Nguruman escarpment and the foothills of Mt

Kilimanjaro This is because the rainfall in the district is strongly influenced by altitude

The temperatures in the district also vary according to altitude Mean maximum of 34ordmC around

L Magadi and a mean minimum of 10ordmC on the foothills of Kilimanjaro have been recorded

Page | 5

Moisture deficit is also observed in the greater part of the year This gives the district a dry

season of between 7-9 months

As for the region around Ongata Rongai the climate is warm and temperate There is significant

rainfall throughout the year in Ongata Rongai The average annual temperature in Ongata Rongai

is 183 degC About 844 mm of precipitation falls annually

223 Topography and GeologyThe main physical features in the district are plains and occasional hills and valleys Several

valleys dissect the plains and its physiography is influenced by geology The land rises from

500m asl around L Magadi to 2500m asl in the Ngong hills area Ongata Rongai lies at

approximately 1731m asl The area slopes as you move towards Ongata Rongai town from

Kiserian and Ngong

The ground surface represents eroded remnants of a former volcanic or string of volcanoes that

previously measured over eleven kilometres in diameter The area is covered mainly by black

cotton soils which is essentially not suitable for farming (Kajiado District Environment Action

Plan 2009-2013)

224 Socio-economic Infrastructure

2241 AdministrationOngata Rongai is one of the locations in Ngong Division It covers Ongata Rongai and Ole

Kasasi sub-locations It is under Kajiado north constituency and Kajiado County It has one of

the highest population growth rates with its population increasing after every census since 2009

2242 EducationOngata Rongai has many schools distributed within the area most of them being primary schools

Most of them are private The area basically has a shortage of public schools There are two main

universities which are within the area namely Africa Nazarene University and Adventist

University of Africa Catholic University of East Africa is also located a few kilometers from the

town itself There are also quite a number of ECD schools and high schools in the area (Kajiado

District Environment Action Plan 2009-2013)

Page | 6

2243 Health FacilitiesOngata Rongai has a number of health facilities most of them being clinics They are both

private and public namely Garlands Aga Khan Kenyatta national hospital These are some of

the hospitals that have opened clinics in the town itself

2244 TransportIn Kajiado district the major roads tend to follow the north-south direction connecting to the

Nairobi-Mombasa road With Nairobi outside Kajiado as the focal point three major road

networks emerge to Magadi to Namanga through Athi River and Kajiado to Loitokitok through

Sultan Hamud and Emali on Mombasa road

The only tarmac roads in the whole district are the Nairobi to Namanga (153kms) Nairobi

Magadi roads which passes through Ongata RongaiKiserian or NgongKiserian (102kms) and

the Kiserian Isinya road The road which leads to the dam itself is an all-weather road Most of

the access roads are not tarmacked and some become impassable during the rainy season

There is a railway line passing through the area but it used to transport Soda ash from Magadi

People in the town also use motorbikes and bicycles to move around and also transport their

goods This is in addition to the donkeys and the carts which are also used (Kajiado District

Environment Action Plan 2009-2013)

2245 Commerce and IndustryThe area is growing at a very high rate This has created business opportunities in the area The

town currently has three large supermarkets These are all accompanied by hotels bars shops

and many more The town also has water vendors who use donkeys as their mode of transport

There are also two market centres in the area one located at Kware and the other known as Soko

mjinga The market day in the area is normally on Sundays

Quarrying is also another main economic activity of the area With new buildings springing up

every day it is one of the main income generating activities of people in the area especially the

ones who live in the low class housing of the area It also has an agro-processing industry located

in Gataka known as Tam-feeds (Kajiado District Environment Action Plan 2009-2013)

Page | 7

2246 AgricultureFarming in the area is practiced in small-scale because the area is highly populated leaving little

land to practice agriculture Most of the crops grown in the area include maize beans bananas

and vegetables Most of the Maasai who live in the area are pastoralists and they keep a large

number of livestock There is a slaughter house located in Kiserian and most of the pastoralists

sell their livestock at the slaughter house (Kajiado District Environment Action Plan 2009-2013

NEMA)

23 Water sources

Basically all sources of freshwater originate from rainfall which is slightly acidic due to

dissolution of carbon dioxide in the atmosphere In form of surface run off it will gather

considerable amounts of organic and mineral matters soil particles microorganisms etc When

surface runoff infiltrates into subsoil level it forms ground water As the ground level water

increases due to varying land formations it oozes out as springs Perennial springs are the

fountain heads of surface water bodies such as streams rivers and lakes

The source of water has a major effect on water system design and hence costs Water from

different sources vary in quality and hence requires varying degrees of treatment The process of

choosing the most suitable source of water supply largely depends on local conditions A source

of water supply can be identified at any of the above stages of water cycle provided it can supply

in sufficient quantities for most periods of the time in the year (Sundaravadivel S V 2007)

When a new water supply is required to meet anticipated increased demand it is common

practice to undertake an assessment of the water resources of the region to consider all possible

sources of supply and then to define an appropriate development plan The range of development

possibilities are as follows

231 Ground water sourcesThese are the sources that tap their water from ground aquifers in the underground rocks or

strata The aquifers are water yielding rocks normally in between two impervious rocks or an

impervious and pervious rock The aquifers are actually water reservoirs which retain water that

has trickled through the pervious or impervious rocks formation commonly termed as water

table

Page | 8

Water tables that are formed in between impervious rocks are in most cases deep and are

permanent water sources while those that form between pervious and impervious rocks are

shallow and are seasonal water suppliers The ground water sources include

Springs

Springs are naturally occurring water source that emerge from the ground They mainly occur in

hilly mountainous areas and river valleys There are mainly two types of springs

a) Gravity springs Occur where ground water emerges at the surface because an impervious

layer prevents it from seeping downwards This happened when an unconfined aquifer emerges

into the open It occurs on sloping ground The flow depends on the water table

b) Artesian springs Occurs where ground water emerges at the surface after confinement The

flow is very nearly constant

Wells

Water well is an excavation created in the ground to access water in the aquifers They greatly

vary in depth depending on the water table The diameter of such excavations determines

whether it is a borehole or a well wells have larger diameters than boreholes It can be excavated

by digging driving boring or drilling to the water table The wells can either be

a) Shallow wells Manual digging can be used to excavate wells to reach the aquifer Their

diameters are large enough to accommodate well diggers with their tools They can be dug up to

a depth of 20-30m usually in loose soils by hand

b) Deep wells These are normally excavated by drilling or by driving methods The depth

normally ranges from 6 -180m deep depending on the level of the water table

232 Surface water sourcesSurface water supply is the water from the lakes reservoirs rivers and streams These water

bodies are formed of water from direct rain runoffs and springs A runoff is the part of rain

water that does not infiltrate the ground or evaporate It flows by gravity into the water body

from the surrounding land The total land area that contributes surface runoff to a river or lake is

called a watershed drainage basin or catchment area

Page | 9

Moisture deficit is also observed in the greater part of the year This gives the district a dry

season of between 7-9 months

As for the region around Ongata Rongai the climate is warm and temperate There is significant

rainfall throughout the year in Ongata Rongai The average annual temperature in Ongata Rongai

is 183 degC About 844 mm of precipitation falls annually

223 Topography and GeologyThe main physical features in the district are plains and occasional hills and valleys Several

valleys dissect the plains and its physiography is influenced by geology The land rises from

500m asl around L Magadi to 2500m asl in the Ngong hills area Ongata Rongai lies at

approximately 1731m asl The area slopes as you move towards Ongata Rongai town from

Kiserian and Ngong

The ground surface represents eroded remnants of a former volcanic or string of volcanoes that

previously measured over eleven kilometres in diameter The area is covered mainly by black

cotton soils which is essentially not suitable for farming (Kajiado District Environment Action

Plan 2009-2013)

224 Socio-economic Infrastructure

2241 AdministrationOngata Rongai is one of the locations in Ngong Division It covers Ongata Rongai and Ole

Kasasi sub-locations It is under Kajiado north constituency and Kajiado County It has one of

the highest population growth rates with its population increasing after every census since 2009

2242 EducationOngata Rongai has many schools distributed within the area most of them being primary schools

Most of them are private The area basically has a shortage of public schools There are two main

universities which are within the area namely Africa Nazarene University and Adventist

University of Africa Catholic University of East Africa is also located a few kilometers from the

town itself There are also quite a number of ECD schools and high schools in the area (Kajiado

District Environment Action Plan 2009-2013)

Page | 6

2243 Health FacilitiesOngata Rongai has a number of health facilities most of them being clinics They are both

private and public namely Garlands Aga Khan Kenyatta national hospital These are some of

the hospitals that have opened clinics in the town itself

2244 TransportIn Kajiado district the major roads tend to follow the north-south direction connecting to the

Nairobi-Mombasa road With Nairobi outside Kajiado as the focal point three major road

networks emerge to Magadi to Namanga through Athi River and Kajiado to Loitokitok through

Sultan Hamud and Emali on Mombasa road

The only tarmac roads in the whole district are the Nairobi to Namanga (153kms) Nairobi

Magadi roads which passes through Ongata RongaiKiserian or NgongKiserian (102kms) and

the Kiserian Isinya road The road which leads to the dam itself is an all-weather road Most of

the access roads are not tarmacked and some become impassable during the rainy season

There is a railway line passing through the area but it used to transport Soda ash from Magadi

People in the town also use motorbikes and bicycles to move around and also transport their

goods This is in addition to the donkeys and the carts which are also used (Kajiado District

Environment Action Plan 2009-2013)

2245 Commerce and IndustryThe area is growing at a very high rate This has created business opportunities in the area The

town currently has three large supermarkets These are all accompanied by hotels bars shops

and many more The town also has water vendors who use donkeys as their mode of transport

There are also two market centres in the area one located at Kware and the other known as Soko

mjinga The market day in the area is normally on Sundays

Quarrying is also another main economic activity of the area With new buildings springing up

every day it is one of the main income generating activities of people in the area especially the

ones who live in the low class housing of the area It also has an agro-processing industry located

in Gataka known as Tam-feeds (Kajiado District Environment Action Plan 2009-2013)

Page | 7

2246 AgricultureFarming in the area is practiced in small-scale because the area is highly populated leaving little

land to practice agriculture Most of the crops grown in the area include maize beans bananas

and vegetables Most of the Maasai who live in the area are pastoralists and they keep a large

number of livestock There is a slaughter house located in Kiserian and most of the pastoralists

sell their livestock at the slaughter house (Kajiado District Environment Action Plan 2009-2013

NEMA)

23 Water sources

Basically all sources of freshwater originate from rainfall which is slightly acidic due to

dissolution of carbon dioxide in the atmosphere In form of surface run off it will gather

considerable amounts of organic and mineral matters soil particles microorganisms etc When

surface runoff infiltrates into subsoil level it forms ground water As the ground level water

increases due to varying land formations it oozes out as springs Perennial springs are the

fountain heads of surface water bodies such as streams rivers and lakes

The source of water has a major effect on water system design and hence costs Water from

different sources vary in quality and hence requires varying degrees of treatment The process of

choosing the most suitable source of water supply largely depends on local conditions A source

of water supply can be identified at any of the above stages of water cycle provided it can supply

in sufficient quantities for most periods of the time in the year (Sundaravadivel S V 2007)

When a new water supply is required to meet anticipated increased demand it is common

practice to undertake an assessment of the water resources of the region to consider all possible

sources of supply and then to define an appropriate development plan The range of development

possibilities are as follows

231 Ground water sourcesThese are the sources that tap their water from ground aquifers in the underground rocks or

strata The aquifers are water yielding rocks normally in between two impervious rocks or an

impervious and pervious rock The aquifers are actually water reservoirs which retain water that

has trickled through the pervious or impervious rocks formation commonly termed as water

table

Page | 8

Water tables that are formed in between impervious rocks are in most cases deep and are

permanent water sources while those that form between pervious and impervious rocks are

shallow and are seasonal water suppliers The ground water sources include

Springs

Springs are naturally occurring water source that emerge from the ground They mainly occur in

hilly mountainous areas and river valleys There are mainly two types of springs

a) Gravity springs Occur where ground water emerges at the surface because an impervious

layer prevents it from seeping downwards This happened when an unconfined aquifer emerges

into the open It occurs on sloping ground The flow depends on the water table

b) Artesian springs Occurs where ground water emerges at the surface after confinement The

flow is very nearly constant

Wells

Water well is an excavation created in the ground to access water in the aquifers They greatly

vary in depth depending on the water table The diameter of such excavations determines

whether it is a borehole or a well wells have larger diameters than boreholes It can be excavated

by digging driving boring or drilling to the water table The wells can either be

a) Shallow wells Manual digging can be used to excavate wells to reach the aquifer Their

diameters are large enough to accommodate well diggers with their tools They can be dug up to

a depth of 20-30m usually in loose soils by hand

b) Deep wells These are normally excavated by drilling or by driving methods The depth

normally ranges from 6 -180m deep depending on the level of the water table

232 Surface water sourcesSurface water supply is the water from the lakes reservoirs rivers and streams These water

bodies are formed of water from direct rain runoffs and springs A runoff is the part of rain

water that does not infiltrate the ground or evaporate It flows by gravity into the water body

from the surrounding land The total land area that contributes surface runoff to a river or lake is

called a watershed drainage basin or catchment area

Page | 9

2243 Health FacilitiesOngata Rongai has a number of health facilities most of them being clinics They are both

private and public namely Garlands Aga Khan Kenyatta national hospital These are some of

the hospitals that have opened clinics in the town itself

2244 TransportIn Kajiado district the major roads tend to follow the north-south direction connecting to the

Nairobi-Mombasa road With Nairobi outside Kajiado as the focal point three major road

networks emerge to Magadi to Namanga through Athi River and Kajiado to Loitokitok through

Sultan Hamud and Emali on Mombasa road

The only tarmac roads in the whole district are the Nairobi to Namanga (153kms) Nairobi

Magadi roads which passes through Ongata RongaiKiserian or NgongKiserian (102kms) and

the Kiserian Isinya road The road which leads to the dam itself is an all-weather road Most of

the access roads are not tarmacked and some become impassable during the rainy season

There is a railway line passing through the area but it used to transport Soda ash from Magadi

People in the town also use motorbikes and bicycles to move around and also transport their

goods This is in addition to the donkeys and the carts which are also used (Kajiado District

Environment Action Plan 2009-2013)

2245 Commerce and IndustryThe area is growing at a very high rate This has created business opportunities in the area The

town currently has three large supermarkets These are all accompanied by hotels bars shops

and many more The town also has water vendors who use donkeys as their mode of transport

There are also two market centres in the area one located at Kware and the other known as Soko

mjinga The market day in the area is normally on Sundays

Quarrying is also another main economic activity of the area With new buildings springing up

every day it is one of the main income generating activities of people in the area especially the

ones who live in the low class housing of the area It also has an agro-processing industry located

in Gataka known as Tam-feeds (Kajiado District Environment Action Plan 2009-2013)

Page | 7

2246 AgricultureFarming in the area is practiced in small-scale because the area is highly populated leaving little

land to practice agriculture Most of the crops grown in the area include maize beans bananas

and vegetables Most of the Maasai who live in the area are pastoralists and they keep a large

number of livestock There is a slaughter house located in Kiserian and most of the pastoralists

sell their livestock at the slaughter house (Kajiado District Environment Action Plan 2009-2013

NEMA)

23 Water sources

Basically all sources of freshwater originate from rainfall which is slightly acidic due to

dissolution of carbon dioxide in the atmosphere In form of surface run off it will gather

considerable amounts of organic and mineral matters soil particles microorganisms etc When

surface runoff infiltrates into subsoil level it forms ground water As the ground level water

increases due to varying land formations it oozes out as springs Perennial springs are the

fountain heads of surface water bodies such as streams rivers and lakes

The source of water has a major effect on water system design and hence costs Water from

different sources vary in quality and hence requires varying degrees of treatment The process of

choosing the most suitable source of water supply largely depends on local conditions A source

of water supply can be identified at any of the above stages of water cycle provided it can supply

in sufficient quantities for most periods of the time in the year (Sundaravadivel S V 2007)

When a new water supply is required to meet anticipated increased demand it is common

practice to undertake an assessment of the water resources of the region to consider all possible

sources of supply and then to define an appropriate development plan The range of development

possibilities are as follows

231 Ground water sourcesThese are the sources that tap their water from ground aquifers in the underground rocks or

strata The aquifers are water yielding rocks normally in between two impervious rocks or an

impervious and pervious rock The aquifers are actually water reservoirs which retain water that

has trickled through the pervious or impervious rocks formation commonly termed as water

table

Page | 8

Water tables that are formed in between impervious rocks are in most cases deep and are

permanent water sources while those that form between pervious and impervious rocks are

shallow and are seasonal water suppliers The ground water sources include

Springs

Springs are naturally occurring water source that emerge from the ground They mainly occur in

hilly mountainous areas and river valleys There are mainly two types of springs

a) Gravity springs Occur where ground water emerges at the surface because an impervious

layer prevents it from seeping downwards This happened when an unconfined aquifer emerges

into the open It occurs on sloping ground The flow depends on the water table

b) Artesian springs Occurs where ground water emerges at the surface after confinement The

flow is very nearly constant

Wells

Water well is an excavation created in the ground to access water in the aquifers They greatly

vary in depth depending on the water table The diameter of such excavations determines

whether it is a borehole or a well wells have larger diameters than boreholes It can be excavated

by digging driving boring or drilling to the water table The wells can either be

a) Shallow wells Manual digging can be used to excavate wells to reach the aquifer Their

diameters are large enough to accommodate well diggers with their tools They can be dug up to

a depth of 20-30m usually in loose soils by hand

b) Deep wells These are normally excavated by drilling or by driving methods The depth

normally ranges from 6 -180m deep depending on the level of the water table

232 Surface water sourcesSurface water supply is the water from the lakes reservoirs rivers and streams These water

bodies are formed of water from direct rain runoffs and springs A runoff is the part of rain

water that does not infiltrate the ground or evaporate It flows by gravity into the water body

from the surrounding land The total land area that contributes surface runoff to a river or lake is

called a watershed drainage basin or catchment area

Page | 9

2246 AgricultureFarming in the area is practiced in small-scale because the area is highly populated leaving little

land to practice agriculture Most of the crops grown in the area include maize beans bananas

and vegetables Most of the Maasai who live in the area are pastoralists and they keep a large

number of livestock There is a slaughter house located in Kiserian and most of the pastoralists

sell their livestock at the slaughter house (Kajiado District Environment Action Plan 2009-2013

NEMA)

23 Water sources

Basically all sources of freshwater originate from rainfall which is slightly acidic due to

dissolution of carbon dioxide in the atmosphere In form of surface run off it will gather

considerable amounts of organic and mineral matters soil particles microorganisms etc When

surface runoff infiltrates into subsoil level it forms ground water As the ground level water

increases due to varying land formations it oozes out as springs Perennial springs are the

fountain heads of surface water bodies such as streams rivers and lakes

The source of water has a major effect on water system design and hence costs Water from

different sources vary in quality and hence requires varying degrees of treatment The process of

choosing the most suitable source of water supply largely depends on local conditions A source

of water supply can be identified at any of the above stages of water cycle provided it can supply

in sufficient quantities for most periods of the time in the year (Sundaravadivel S V 2007)

When a new water supply is required to meet anticipated increased demand it is common

practice to undertake an assessment of the water resources of the region to consider all possible

sources of supply and then to define an appropriate development plan The range of development

possibilities are as follows

231 Ground water sourcesThese are the sources that tap their water from ground aquifers in the underground rocks or

strata The aquifers are water yielding rocks normally in between two impervious rocks or an

impervious and pervious rock The aquifers are actually water reservoirs which retain water that

has trickled through the pervious or impervious rocks formation commonly termed as water

table

Page | 8

Water tables that are formed in between impervious rocks are in most cases deep and are

permanent water sources while those that form between pervious and impervious rocks are

shallow and are seasonal water suppliers The ground water sources include

Springs

Springs are naturally occurring water source that emerge from the ground They mainly occur in

hilly mountainous areas and river valleys There are mainly two types of springs

a) Gravity springs Occur where ground water emerges at the surface because an impervious

layer prevents it from seeping downwards This happened when an unconfined aquifer emerges

into the open It occurs on sloping ground The flow depends on the water table

b) Artesian springs Occurs where ground water emerges at the surface after confinement The

flow is very nearly constant

Wells

Water well is an excavation created in the ground to access water in the aquifers They greatly

vary in depth depending on the water table The diameter of such excavations determines

whether it is a borehole or a well wells have larger diameters than boreholes It can be excavated

by digging driving boring or drilling to the water table The wells can either be

a) Shallow wells Manual digging can be used to excavate wells to reach the aquifer Their

diameters are large enough to accommodate well diggers with their tools They can be dug up to

a depth of 20-30m usually in loose soils by hand

b) Deep wells These are normally excavated by drilling or by driving methods The depth

normally ranges from 6 -180m deep depending on the level of the water table

232 Surface water sourcesSurface water supply is the water from the lakes reservoirs rivers and streams These water

bodies are formed of water from direct rain runoffs and springs A runoff is the part of rain

water that does not infiltrate the ground or evaporate It flows by gravity into the water body

from the surrounding land The total land area that contributes surface runoff to a river or lake is

called a watershed drainage basin or catchment area

Page | 9

Water tables that are formed in between impervious rocks are in most cases deep and are

permanent water sources while those that form between pervious and impervious rocks are

shallow and are seasonal water suppliers The ground water sources include

Springs

Springs are naturally occurring water source that emerge from the ground They mainly occur in

hilly mountainous areas and river valleys There are mainly two types of springs

a) Gravity springs Occur where ground water emerges at the surface because an impervious

layer prevents it from seeping downwards This happened when an unconfined aquifer emerges

into the open It occurs on sloping ground The flow depends on the water table

b) Artesian springs Occurs where ground water emerges at the surface after confinement The

flow is very nearly constant

Wells

Water well is an excavation created in the ground to access water in the aquifers They greatly

vary in depth depending on the water table The diameter of such excavations determines

whether it is a borehole or a well wells have larger diameters than boreholes It can be excavated

by digging driving boring or drilling to the water table The wells can either be

a) Shallow wells Manual digging can be used to excavate wells to reach the aquifer Their

diameters are large enough to accommodate well diggers with their tools They can be dug up to

a depth of 20-30m usually in loose soils by hand

b) Deep wells These are normally excavated by drilling or by driving methods The depth

normally ranges from 6 -180m deep depending on the level of the water table

232 Surface water sourcesSurface water supply is the water from the lakes reservoirs rivers and streams These water

bodies are formed of water from direct rain runoffs and springs A runoff is the part of rain

water that does not infiltrate the ground or evaporate It flows by gravity into the water body

from the surrounding land The total land area that contributes surface runoff to a river or lake is

called a watershed drainage basin or catchment area

Page | 9

The volume of water available for municipal supply depends mostly on the amount of rainfall It

also depends on the size of the watershed the slope of the ground the type of soil and

vegetation and the type of land use (World Vision WASH manual 2012)

24 Water Demand

Water demand varies for the different uses These can be classified as follows

Domestic demand

This includes water used required in private building for drinking bathing gardening sanitary

purpose etc

Industrial demand

It represents the water demand of industries which earlier exist or are likely to be started in

future Water used for industrial purposes may be incorporated into products or used for

processing washing cooling sanitation or maintenance

Commercial demand

This is the water requirement for institutions hotels schools colleges and offices It should be

anticipated that the future increase in commercial activity would be directly related to the growth

of population

Fire demand

In populated or industrial areas fires generally breakout and may lead to damage For control

that situation requires sufficient quantity of water which is the fire demand

Livestock demand

Includes water associated with the production of meat milk poultry eggs and wool The kind of

stock includes dairy cows and heifers beef cattle and calves sheep and lambs goats hogs and

pigs and poultry Poultry includes chickens turkeys ducks geese pheasants and pigeons

(Susan S Hutson et al 2000)

Water demand projections should normally be made for the ldquoinitialrdquo the ldquofuturerdquo and the

ldquoultimaterdquo year

Page | 10

The ldquoinitialrdquo year is the year when the supply is expected to be taken into operation that may be

assumed to be 0-5 years from the date of the commencement of the preliminary design The

ldquofuturerdquo is 10 years and the ldquoultimaterdquo year 20 years from the initial year Once the initial future

and ultimate years have been determined for a project they should not normally be changed

during the design period

A water supply should normally be designed for the ultimate demand However phasing of the

implementation will often become a financial necessity and the possibilities of phasing should

therefore be examined using the initial and future demand projections (Water Design Manual

2005 Kenya)

25 Population projections

Design of water supply and sanitation scheme is based on the projected population of a particular

city estimated for the design period Any underestimated value will make system inadequate for

the purpose intended similarly overestimated value will make it costly Changes in the

population of the city over the years occur and the system should be designed taking into

account the population at the end of the design period

Factors affecting changes in population are

increase due to births

decrease due to deaths

increasedecrease due to migration

increase due to annexation

The present and past population record for the city can be obtained from the census population

records After collecting these population figures the population at the end of design period is

predicted using various methods as suitable for that city considering the growth pattern followed

by the city (Population Forecasting NPTEL IIT Kharagpur Web Courses)

There are five different methods used These are

Page | 11

a Arithmetical Increase Method

This method is suitable for large and old cities with considerable development If it is used for

small average or comparatively new cities it will give lower population estimate than actual

value In this method the average increase in population per year is calculated from the past

census reports This increase is added to the present population to find out the population of the

next year Thus it is assumed that the population is increasing at constant rate

Hence dPdt = C ie rate of change of population with respect to time is constant

Therefore Population after nth year will be Pn= P + nC

Where Pn = population after lsquonrsquo year and

P = present population

b Geometrical Progression Method

In this method the percentage increase in population from decade to decade is assumed to remain

constant Geometric mean increase is used to find out the future increment in population Since

this method gives higher values it should be applied for a new industrial town at the beginning

of development for only few years The population at the end of nth year lsquoPnrsquo can be estimated

as

Pn = P (1+ r)n

Where r = geometric mean (population growth factor in )

P = Present population

n = number of years

c Incremental Increase Method

This method is modification of arithmetical increase method and it is suitable for an average size

town under normal condition where the growth rate is found to be in increasing order While

adopting this method the increase in increment is considered for calculating future population

Page | 12

The incremental increase is determined for each year from the past population and the average

value is added to the present population along with the average rate of increase Hence

population after nth year is Pn = P+ nX + n (n+1)2Y

Where Pn = Population after nth decade

X = Average increase

Y = Incremental increase

d Graphical Method

In this method the populations of last few decades are correctly plotted to a suitable scale on

graph The population curve is smoothly extended for getting future population This extension

should be done carefully and it requires proper experience and judgment The best way of

applying this method is to extend the curve by comparing with population curve of some other

similar cities having the similar growth condition

e Comparative Graphical methods

In this method the census populations of cities already developed under similar conditions are

plotted The curve of past population of the city under consideration is plotted on the same graph

The curve is extended carefully by comparing with the population curve of some similar cities

having the similar condition of growth The advantage of this method is that the future

population can be predicted from the present population even in the absence of some of the past

census report

f Masterplan Methods

The big and metropolitan cities are generally not developed in haphazard manner but are

planned and regulated by local bodies according to master plan The master plan is prepared for

next 25 to 30 years for the city According to the master plan the city is divided into various

zones such as residence commerce and industry The population densities are fixed for various

zones in the master plan

From this population density total water demand and wastewater generation for that zone can be

worked out By this method it is very easy to access precisely the design population

Page | 13

g Logistic Curve Method

This method is used when the growth rate of population due to births deaths and migrations

takes place under normal situation and it is not subjected to any extraordinary changes like

epidemic war earth quake or any natural disaster etc and the population follows the growth

curve characteristics of living things within limited space and economic opportunity If the

population of a city is plotted with respect to time the curve so obtained under normal condition

looks like S-shaped curve and is known as logistic curve

26 Water distribution

The water distribution system or reticulation system serves to convey the water from the source

and treated when necessary to the point where it is delivered to the users For small community

water supplies the distribution system and any provision for water storage should be kept

simple Even so it may represent a substantial capital investment and the design must be done

properly

Generally the distribution system of a small community water supply is designed to cater for the

domestic and other residential water requirements Stock watering and garden irrigation may also

be provided

The water demand varies considerably in the course of a day Water consumption is highest

during the hours that water is used for personal hygiene and cleaning and when food preparation

and washing of clothes are done During the night the water use will be lowest

This variation in flow can be dealt with by operating pumps in parallel andor building balancing

storage in the system For small community water supplies the distribution system with water

storage like a service reservoir is the preferable option given that supplies of electricity or diesel

to power pumps will usually be unreliable

Service reservoirs serve to accumulate and store water during the night so that it can be supplied

during the daytime hours of high water demand

Page | 14

It is necessary to maintain a sufficient pressure in the distribution system to protect it against

contamination by the ingress of polluted seepage water A minimum pressure of 5-10m head

should be sufficient in most cases (Hofkes E H et al 1981)

Types of distribution systems

There are basically two main layouts of a distribution network

bull Branched configuration (figure 22)

bull Looped (grid) configuration (figure 22)

Branched networks are predominantly used for small-capacity community supplies delivering the

water mostly through public standpipes and having few house connections if any Although

adequate having in mind simplicity and acceptable investment costs branched networks have

some disadvantages

Low reliability which affects all users located downstream of any breakdown in the

system

Danger of contamination caused by the possibility that a large part of network will be

without water during irregular situations

Accumulation of sediments due to stagnation of the water at the system ends (ldquodeadrdquo

ends) occasionally resulting in taste and odour problems

Fluctuating water demand producing rather large pressure variations

Page | 15

Figure 22 Branched and looped distribution system

Branched systems are easy to design The direction of the water flow and the flow rates can

readily be determined for all pipes This is different in looped distribution networks where

consumers can be supplied from more than one direction Looped networks greatly improve the

hydraulics of the distribution system This is of major importance in the event that one of the

mains is out of operation for cleaning or repair

A looped network usually has a skeleton of secondary mains that can also be in a form of branch

one loop or a number of loops From there the water is conveyed towards the distribution pipes

and further to the consumers The secondary mains are connected to one or more loops or rings

The network in large (urban) distribution systems will be much more complex essentially a

combination of loops and branches with lots of interconnected pipes that requires many valves

and special parts as shown below in figure 23 To save on equipment costs over-crossing pipes

that are not interconnected may be used but at the cost of reduced reliability as shown below in

figure 24

Page | 16

Figure 23 Fully interconnected pipes

Figure 24 Overcrossing single pipes

Points at which the water is delivered to the users are called service connections The number

and type of service connections has considerable influence on the choice of a network layout

Page | 17

The following types of service connections may be distinguished

House connection

Yard connection

Group connection

Public standpipe

A house connection is a water service pipe connected with in-house plumbing to one or more

taps eg in the kitchen and bathroom Usually 38 inch (9 mm) and 12 inch (12 mm) taps are

used A typical layout is shown in figure 25

Figure 25 House connection

The service pipe is connected to the distribution main in the street by means of a T-piece on

small-diameter pipes a special insert piece or a saddle on larger-size secondary pipes A special

insert piece is mostly used for cast iron and ductile iron pipes

A yard connection is quite similar to a house connection the only difference being that the tap is

placed in the yard outside the house No in-house piping and fixtures are provided as shown

below in figure 26

Page | 18

Figure 26 Yard connection

Plastic (polyvinyl chloride or polyethylene) cast iron and galvanized steel pipes are used for

both house connections and yard connections

Group connections are outside taps that are shared by a clearly defined group of households

often neighbours Each family may pay the same (flat) share or contributions may be weighed

according to the estimated volume of water each family consumes Consumption estimates may

be based on indicators such as family size and composition and types of use by the different

households Sometimes the taps can be locked and a local committee holds the key and manages

the use and financing

Public standpipes can have one or more taps Single-tap and double-tap standpipes are the most

common types in rural areas They are made of brickwork masonry or concrete or use wooden

poles and similar materials The design should be done in close consultation with the users

(especially women) in order to arrive at an ergonomically optimal solution Standpipes may have

platforms at different levels making it easy for adults and children to use them with containers

of different sizes Examples are shown in figures 27 Cattle watering andor washing andor

bathing facilities may be constructed nearby The design and often also the construction are best

done in consultation and with participation of the user households ie both men and women

Public taps drawing from a small reservoir (cistern) represent an alternative method of water

distribution

Page | 19

Figure 27 Public Standpipes

Each standpipe should be situated at a suitable point within the community area in order to limit

the distance the water users have to go to collect their water The walking distance for the most

distant user of a standpipe should whenever possible be limited to 200 m in sparsely populated

rural areas 500 m may be acceptable The required discharge capacity of a standpipe normally is

about 14-18 litresminute at each outlet A single-tap standpipe should preferably be used by not

more than 40-70 people a multiple-tap standpipe may provide a reasonable service for up to

250-300 persons in no case should the number of users dependent on one standpipe exceed 500

Public standpipes can operate at a low pressure Distribution systems that serve only standpipes

may therefore use low pressure piping whereas the pipes for distribution systems with house

connections generally have to be of a higher pressure class Water collected at a public standpipe

will have to be carried home in a container This means that the water that was safe at the

moment of drawing may no longer be so at the moment it is used in the house Water

consumption from standpipes generally is not higher than 20-30 litres per person per day

This consumption increases when other facilities are added to reduce the amount of water

women and children have to carry home Water use for other purposes other than drinking and

cooking is likely to be curtailed when the water has to be fetched from a standpipe

Page | 20

Yard and house connections will usually encourage a more generous water use for personal

hygiene and cleaning purposes Wastage of water from standpipes can be a serious problem

especially when users fail to turn off the taps Furthermore poor drainage of spilled water may

cause stagnant pools of dirty water with the associated health hazards It is also not uncommon

for the taps to be damaged by the users and pilferage sometimes occurs These problems occur

particularly when designs do not meet the user requirements

In spite of their shortcomings group connections and public standpipes are really the only

practical options for water distribution at minimum cost to a large number of people who cannot

afford the much higher costs of house or yard connections In fact housing is frequently not

suitably constructed to allow the installation of internal plumbing It would often be impossible

for a small community to obtain the substantial capital for a water distribution system with house

connections Also the costs of adequate disposal of the considerable amounts of wastewater

generated by a house connected water supply service would place an additional heavy financial

burden on the community Consequently public standpipes have to be provided and the principal

concern should be to lessen their inherent shortcomings as much as possible (Hofkes E H et al

1981)

261 Water Demand Variation

The daily water demand in a community area will vary during the year due to seasonal climate

patterns the work situation and other factors such as cultural or religious occasions The

maximum daily demand is usually estimated by adding 10-30 to the average daily demand

Thus the peak factor for the daily water demand (k1) is 11-13

The hourly variation in domestic water demand during the day is much greater Generally two

peak periods can be observed one in the morning and one late in the afternoon as shown in fig

28 below The peak hour demand can be expressed as the average hourly demand multiplied by

the hourly peak factor (k2) For a particular distribution area this factor depends on the size and

character of the community served The hourly peak factor tends to be high for small villages It

is usually lower for larger communities and small towns Where roof tanks or other water storage

vessels are common the hourly peak factor will be further reduced

Page | 21

Usually the factor k2 is chosen in the 15-25 range Where a pipe connection is designed to

supply a small group of consumers a higher value should be adopted because of the effects of

instantaneous demand A water distribution system is typically designed to cater for the

maximum hourly demand This peak demand may then be computed as k1 x k2 x average hourly

demand (Hofkes E H et al 1981)

Figure 28 Variation of domestic water demand during the day

262 Balancing storageWithout storage of water in the distribution area the source of supply and the water treatment

plant would have to be able to follow all fluctuations in the water demand of the community

served This is generally not economical and sometimes not even technically feasible The

design capacities of the various components of a water supply system are usually chosen as

indicated

In summary

System component Design capacity

Water source Peak day water demand

Raw water main Peak day water demand

Treatment plant Peak day water demand

Page | 22

Transmission main Peak day water demand

The service reservoir is provided to balance the (constant) supply rate from the water

sourcetreatment plant with the fluctuating water demand in the distribution area The storage

volume should be large enough to accommodate the cumulative differences between water

supply and demand (Hofkes E H et al 1981)

Figure 29 Design capacities for water supply system components

263 Distribution system design

A typical range of velocities in distribution pipes is between 05 and 10 ms occasionally up to 2

ms The hydraulic gradients usually range between 1 and 5 mkm occasionally up to 10 mkm

In case of smaller pipes D lt 50 mm the hydraulic gradient can even be higher

The pressure criterion is dependent on topographic conditions availability of water at the source

and overall condition of the pipes The minimum pressures should not drop below 5-10 meter

water column In larger distribution areas where water scarcity is not an issue the minimum

pressures can range between 20 and 30 mwc above street level where there are house

connections This is sufficient for supply of 2-3 storey buildings Pressures higher than 60 mwc

Page | 23

should be avoided in general due to increased leakage and risks of bursts especially in poorly

maintained networks

After choosing a preliminary supply scheme (gravitypumping) and type of network layout

(branchedlooped) with its main components the distribution area is divided into a number of

demand districts according to the topography land use classification and density of population

Boundaries may be drawn along rivers roads high points or other features that distinguish each

district The secondary mains and distribution pipes can then be plotted on the plan

Once all the sectors are fixed the population for each district can be estimated or computed from

data collected in the community involvement process The water demand per district is then

computed using per capita water usage figures for domestic water consumption and selected

values for the other non-domestic water requirements including productive uses This per capita

usage figure may vary depending on the water service level that the community in the concerned

district has decided on (Hofkes E H et al 1981)

264 Pipes

The water from public water supply system to individual buildings is supplied through pipes A

large proportion of capital is invested on pipes while designing water supply distribution system

The following factors should be considered in selection of pipes

Strength of pipe

Water carrying capacity

Life and durability of pipe

Expenditure on transportation

Jointing process maintenance and repairs

Several different types of pipe are used in distribution systems They all have advantages and

disadvantages related to cost installation strength and corrosion The most common types of

pipe are known by their abbreviations They include Cast Iron Pipe (CIP) Ductile Iron Pipe

(DIP) Steel Pipe (ST) Asbestos-Cement Pipe (AC) Polyvinyl Chloride Pipe (PVC) and

Unplasticised Polyvinyl Chloride Pipe (UPVC)

Page | 24

UPVC (unplasticized polyvinylchloride) pipes and fittings exhibit excellent resistance to

aggressive environments both naturally occurring and as a result of industrial activity They are

resistant to almost all types of corrosion either chemical or electrochemical in nature

Since uPVC is a non-conductor galvanic and electro chemical effects do not occur in UPVC

pipes

UPVC Pipes and fittings are often used in the following circumstances

bull For drinking water pipe distribution systems both main and supply lines

bull Sewer and discharge pipe systems

Steel pipe is lighter than iron pipe and is easier to handle and install It is more flexible than iron

pipe and doesnt require as much care when bedded in the trench The main disadvantage of steel

pipe is that it is very susceptible to corrosion and should be coated both inside and outside It

doesnt have the same bearing strength that cast or ductile iron does and may collapse under

vacuum conditions Steel pipe may be joined the same way that cast is joined It may also be

joined using threaded connections (Sacramento Water Distribution System Manual 2000)

Cast iron and ductile iron pipe are known for their strength and load bearing capacity Most of

the iron pipe that has been installed in the past 40 years is ductile iron pipe Ductile iron is

stronger and less rigid than gray cast iron pipe The main disadvantages of iron pipe are that it is

heavy and subject to corrosion from the inside and the outside It should be coated with a

corrosion resistant external coating and in certain soil conditions may require some type of

cathodic protection to achieve its normal service life

Cast and ductile iron pipes can be joined by several different means Flanged joints are used

above ground The most common means of joining them underground are the bell and spigot (O-

ring push-on) and the mechanical joint (MJ) connections Care must be taken when installing and

bedding CIP and DIP are both brittle and dont flex The bell holes should only be as wide as the

bell portion of the pipe Otherwise stresses from improper bedding can cause it to crack

(Sacramento Water Distribution System Manual 2000)

Page | 25

Page | 26

2641 Pipes Appurtenances

Valves

Valves are used to control flow in a water system Most of the valves in a distribution system are

installed for isolation of sections of piping for maintenance and repair Control valves like

pressure reducing valves altitude valves pressure relief valves pressure sustaining valves and

pump control valves are designed to control pressures and throttle flows to prevent damage to the

system Air relief valves can vent trapped air from the system Check valves allow water to flow

only in one direction

Valves may be operated by hand or by actuator Actuators generally are electric and may be

operated locally or by remote control Where there is no local power supply portable power

packs may be used

Some examples of valves include

Gate Valve - Gate valves are the most common valves in a distribution system They are used for

isolation of equipment and piping They should never be used to throttle flow This will cause

damage to the valve face Open gate valves have the less friction loss than any other type of

valve Gate valves can have plug type disks or split gates Split gates are used in higher pressure

applications

Butterfly valves - Butterfly valves serve the same purpose as gate valves These valves usually

open and close with a quarter of a turn of the valve disc Larger valves will have a gear box on

the stem and will require a number of turns to open Butterfly valves are easier to open than gate

valves usually without the need for a bypass but have more friction loss when open They can

also be used for throttling flow without damaging the disc Caution should be used when filling a

line through a butterfly valve

Air Release Valve - Air release valves are used to allow air that may be trapped in the line to

escape The trapped air can create pressure and pumping problems milky-water complaints and

pressure spikes that resemble water hammer They are very useful in systems that are in hilly

country They should be located at the top of hills where the trapped air will collect

Page | 27

They are also used on booster pumps and wells to removed trapped air Combination air release

valves will also let air in when a vacuum occurs This is done to protect the piping They can also

be used to vent a line that is being drained All air-release valves should be equipped with

isolating valves for easy removal and repair of the air valves (Sacramento Water Distribution

System Manual 2000)

Section Valves - The valves should be placed in such a way that rationing of water can be done

by closing suitable parts of the supply for certain periods Whenever possible the section valves

should be placed in a joint valve chamber with air valves or washouts and upstream of these

valves In urban areas where fire-fighting is provided for there should be an isolating valve

downstream each fire hydrant (Water Design Manual 2005 Kenya)

Valve chambers

Large valves on trunk pipelines should be located in accessible chambers to facilitate

maintenance Smaller gate valves are usually buried Valve chambers should be at least 1000 x

1000mm internally There must not be UPVC-pipes within the chamber The cover should be

lockable The chamber should be drained through the floor or through a drain pipe

Hydrants

The fire insurance rates for residents on the system will be dependent in part on the proper

spacing and discharge capabilities of the fire hydrants in the system Hydrants should not be

more than 500-600 feet apart in residential districts The spacing requirements in industrial and

rural districts may vary They should be located at the end of every dead end line Hydrants

should be operated every 6 months and flow tested annually

Fire hydrants should never be placed on less than a 6 inch line if it is to be used for fire

protection In addition to provide fire protection hydrants can also be useful for flushing lines

venting lines as they are filled and pressure and flow testing Hydrants on smaller lines (4 inch

and down) will not supply enough water to fight a fire but may be used to flush dead end lines

Page | 28

Thrust Blocks

Wherever a bend elbow tee or dead-end exists in a pipeline having flexible joints a force is

exerted which tends to open the joints nearest the fittings The magnitude of this force varies

with the amount of bend the diameter of pipe and the pressure inside the pipe When

determining the resultant thrust for a given pipe it is advisable to use the maximum working

pressure anticipated in the pipe plus an allowance for surges or water hammer

Once the resultant thrust has been determined for a particular bend it becomes necessary to

provide a backing block of such size to resist the thrust The thrust must ultimately be borne by

the side of the pipe trench and the surrounding soil The purpose of the backing block is to

spread the thrust over an area sufficiently large that the undisturbed earth can support it

2642 Washouts

A washout is seldom used for scouring or washing out a main because its diameter is too small to

create sufficient flow velocity in the main to wash out debris Its principal use is for emptying a

main or for the removal of stagnant or dirty water

Primary washouts may be installed to drain to a watercourse the majority of the length between

section valves Secondary washouts of smaller diameter can then be used to empty undrained

subsections as required Sizes particularly primary washouts need to be calculated according to

the draindown time (Twort 5th Edition)

2643 Break Pressure tanks

Static head is the difference in elevation from the source to any point on the ground profile

Static head must always be considered because excessive pressure in the pipe from the elevation

head can rapture the pipe or pipe connections Piping is rated by its ability to withstand an

internal pressure without breaking The ability is a function of the type of pipe material and

thickness of the wall pipe

Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure

that will rupture the pipe or cause failures at the joints

Page | 29

The function of a break pressure tank is to allow the flow to discharge into the atmosphere

thereby reducing its hydrostatic pressure to zero and establishing a new static level A general

rule of thumb is that the static head at any given point within the conduction line should not

exceed 100m of head There is no minimum required capacity for a break pressure tank as long

as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)

Page | 30

Chapter Three

30 METHODOLOGY

31 Introduction

Different data was needed for the design of a water supply system in Ongata Rongai Methods of

data collection were established beforehand to ensure the process was efficient Once the data

was collected it was analyzed to produce an outcome that satisfied the objective of the report

The data collected included

a) Population of the area

b) Land use

c) Topographical data

d) Existing water supply

e) Information on water consumption per capita in the area

In order to obtain this data various data collection methods were used as shown below

32 Data collection methods

Various methods were employed to collect data needed for the design of the system Both

primary and secondary data was needed The quantitative methods employed were to enable me

to obtain firsthand information needed for the project These include

a) Questionnaires

b) Interviews

c) Literature review

d) Government agencies

e) Direct observation

321 QuestionnairesQuestionnaires were prepared to aid with the collection of data The questionnaires were given to

the relevant parties In order to obtain an overview of water use in the area the questionnaire was

handed to the community for a brief description on how they use the water

Page | 31

With regards to the existing water supply it was necessary to involve Oloolaiser Water with the

use of questionnaires to obtain information on their existing system

322 InterviewsIn addition to questionnaires face to face interviews were also conducted The interviews were

done to collect data on the challenges facing the existing supply of water and the sources

available for people in the area These interviews were carried out with the members living in the

project area

Information on the proposed source was also required This particular interview was conducted

with the engineer who designed the dam itself The current population of the town and the

change of boundaries in the area over the past twenty years information was obtained from an

interview conducted with the technical manager at Oloolaiser Water and Sewerage Company

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area

323 Literature reviewDifferent reports were reviewed to get information in various areas This included the past

census reports to obtain the population of people in the area Information on land use and project

location description was also obtained from the NEMA Environmental Action plan for Kajiado

Land use data was necessary to establish where the pipeline would pass

324 Government AgenciesIn order to collect topographical data a map from the Survey of Kenya was obtained for the area

This map had information on the roads contours rivers all the natural and man-made features

which were necessary for the design of the system Information on sources of water supply in the

area was also obtained from the Oloolaiser water and sewerage company who are the water

service providers in the area

325 Direct ObservationDirect observation for information on settlement and land use was necessary because of the rate

at which the town is growing This was especially needed for the land adjacent to the road

because that was where the pipeline would pass and also to consider alternative routes for the

pipeline

Page | 32

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

The ldquoinitialrdquo year is the year when the supply is expected to be taken into operation that may be

assumed to be 0-5 years from the date of the commencement of the preliminary design The

ldquofuturerdquo is 10 years and the ldquoultimaterdquo year 20 years from the initial year Once the initial future

and ultimate years have been determined for a project they should not normally be changed

during the design period

A water supply should normally be designed for the ultimate demand However phasing of the

implementation will often become a financial necessity and the possibilities of phasing should

therefore be examined using the initial and future demand projections (Water Design Manual

2005 Kenya)

25 Population projections

Design of water supply and sanitation scheme is based on the projected population of a particular

city estimated for the design period Any underestimated value will make system inadequate for

the purpose intended similarly overestimated value will make it costly Changes in the

population of the city over the years occur and the system should be designed taking into

account the population at the end of the design period

Factors affecting changes in population are

increase due to births

decrease due to deaths

increasedecrease due to migration

increase due to annexation

The present and past population record for the city can be obtained from the census population

records After collecting these population figures the population at the end of design period is

predicted using various methods as suitable for that city considering the growth pattern followed

by the city (Population Forecasting NPTEL IIT Kharagpur Web Courses)

There are five different methods used These are

Page | 11

a Arithmetical Increase Method

This method is suitable for large and old cities with considerable development If it is used for

small average or comparatively new cities it will give lower population estimate than actual

value In this method the average increase in population per year is calculated from the past

census reports This increase is added to the present population to find out the population of the

next year Thus it is assumed that the population is increasing at constant rate

Hence dPdt = C ie rate of change of population with respect to time is constant

Therefore Population after nth year will be Pn= P + nC

Where Pn = population after lsquonrsquo year and

P = present population

b Geometrical Progression Method

In this method the percentage increase in population from decade to decade is assumed to remain

constant Geometric mean increase is used to find out the future increment in population Since

this method gives higher values it should be applied for a new industrial town at the beginning

of development for only few years The population at the end of nth year lsquoPnrsquo can be estimated

as

Pn = P (1+ r)n

Where r = geometric mean (population growth factor in )

P = Present population

n = number of years

c Incremental Increase Method

This method is modification of arithmetical increase method and it is suitable for an average size

town under normal condition where the growth rate is found to be in increasing order While

adopting this method the increase in increment is considered for calculating future population

Page | 12

The incremental increase is determined for each year from the past population and the average

value is added to the present population along with the average rate of increase Hence

population after nth year is Pn = P+ nX + n (n+1)2Y

Where Pn = Population after nth decade

X = Average increase

Y = Incremental increase

d Graphical Method

In this method the populations of last few decades are correctly plotted to a suitable scale on

graph The population curve is smoothly extended for getting future population This extension

should be done carefully and it requires proper experience and judgment The best way of

applying this method is to extend the curve by comparing with population curve of some other

similar cities having the similar growth condition

e Comparative Graphical methods

In this method the census populations of cities already developed under similar conditions are

plotted The curve of past population of the city under consideration is plotted on the same graph

The curve is extended carefully by comparing with the population curve of some similar cities

having the similar condition of growth The advantage of this method is that the future

population can be predicted from the present population even in the absence of some of the past

census report

f Masterplan Methods

The big and metropolitan cities are generally not developed in haphazard manner but are

planned and regulated by local bodies according to master plan The master plan is prepared for

next 25 to 30 years for the city According to the master plan the city is divided into various

zones such as residence commerce and industry The population densities are fixed for various

zones in the master plan

From this population density total water demand and wastewater generation for that zone can be

worked out By this method it is very easy to access precisely the design population

Page | 13

g Logistic Curve Method

This method is used when the growth rate of population due to births deaths and migrations

takes place under normal situation and it is not subjected to any extraordinary changes like

epidemic war earth quake or any natural disaster etc and the population follows the growth

curve characteristics of living things within limited space and economic opportunity If the

population of a city is plotted with respect to time the curve so obtained under normal condition

looks like S-shaped curve and is known as logistic curve

26 Water distribution

The water distribution system or reticulation system serves to convey the water from the source

and treated when necessary to the point where it is delivered to the users For small community

water supplies the distribution system and any provision for water storage should be kept

simple Even so it may represent a substantial capital investment and the design must be done

properly

Generally the distribution system of a small community water supply is designed to cater for the

domestic and other residential water requirements Stock watering and garden irrigation may also

be provided

The water demand varies considerably in the course of a day Water consumption is highest

during the hours that water is used for personal hygiene and cleaning and when food preparation

and washing of clothes are done During the night the water use will be lowest

This variation in flow can be dealt with by operating pumps in parallel andor building balancing

storage in the system For small community water supplies the distribution system with water

storage like a service reservoir is the preferable option given that supplies of electricity or diesel

to power pumps will usually be unreliable

Service reservoirs serve to accumulate and store water during the night so that it can be supplied

during the daytime hours of high water demand

Page | 14

It is necessary to maintain a sufficient pressure in the distribution system to protect it against

contamination by the ingress of polluted seepage water A minimum pressure of 5-10m head

should be sufficient in most cases (Hofkes E H et al 1981)

Types of distribution systems

There are basically two main layouts of a distribution network

bull Branched configuration (figure 22)

bull Looped (grid) configuration (figure 22)

Branched networks are predominantly used for small-capacity community supplies delivering the

water mostly through public standpipes and having few house connections if any Although

adequate having in mind simplicity and acceptable investment costs branched networks have

some disadvantages

Low reliability which affects all users located downstream of any breakdown in the

system

Danger of contamination caused by the possibility that a large part of network will be

without water during irregular situations

Accumulation of sediments due to stagnation of the water at the system ends (ldquodeadrdquo

ends) occasionally resulting in taste and odour problems

Fluctuating water demand producing rather large pressure variations

Page | 15

Figure 22 Branched and looped distribution system

Branched systems are easy to design The direction of the water flow and the flow rates can

readily be determined for all pipes This is different in looped distribution networks where

consumers can be supplied from more than one direction Looped networks greatly improve the

hydraulics of the distribution system This is of major importance in the event that one of the

mains is out of operation for cleaning or repair

A looped network usually has a skeleton of secondary mains that can also be in a form of branch

one loop or a number of loops From there the water is conveyed towards the distribution pipes

and further to the consumers The secondary mains are connected to one or more loops or rings

The network in large (urban) distribution systems will be much more complex essentially a

combination of loops and branches with lots of interconnected pipes that requires many valves

and special parts as shown below in figure 23 To save on equipment costs over-crossing pipes

that are not interconnected may be used but at the cost of reduced reliability as shown below in

figure 24

Page | 16

Figure 23 Fully interconnected pipes

Figure 24 Overcrossing single pipes

Points at which the water is delivered to the users are called service connections The number

and type of service connections has considerable influence on the choice of a network layout

Page | 17

The following types of service connections may be distinguished

House connection

Yard connection

Group connection

Public standpipe

A house connection is a water service pipe connected with in-house plumbing to one or more

taps eg in the kitchen and bathroom Usually 38 inch (9 mm) and 12 inch (12 mm) taps are

used A typical layout is shown in figure 25

Figure 25 House connection

The service pipe is connected to the distribution main in the street by means of a T-piece on

small-diameter pipes a special insert piece or a saddle on larger-size secondary pipes A special

insert piece is mostly used for cast iron and ductile iron pipes

A yard connection is quite similar to a house connection the only difference being that the tap is

placed in the yard outside the house No in-house piping and fixtures are provided as shown

below in figure 26

Page | 18

Figure 26 Yard connection

Plastic (polyvinyl chloride or polyethylene) cast iron and galvanized steel pipes are used for

both house connections and yard connections

Group connections are outside taps that are shared by a clearly defined group of households

often neighbours Each family may pay the same (flat) share or contributions may be weighed

according to the estimated volume of water each family consumes Consumption estimates may

be based on indicators such as family size and composition and types of use by the different

households Sometimes the taps can be locked and a local committee holds the key and manages

the use and financing

Public standpipes can have one or more taps Single-tap and double-tap standpipes are the most

common types in rural areas They are made of brickwork masonry or concrete or use wooden

poles and similar materials The design should be done in close consultation with the users

(especially women) in order to arrive at an ergonomically optimal solution Standpipes may have

platforms at different levels making it easy for adults and children to use them with containers

of different sizes Examples are shown in figures 27 Cattle watering andor washing andor

bathing facilities may be constructed nearby The design and often also the construction are best

done in consultation and with participation of the user households ie both men and women

Public taps drawing from a small reservoir (cistern) represent an alternative method of water

distribution

Page | 19

Figure 27 Public Standpipes

Each standpipe should be situated at a suitable point within the community area in order to limit

the distance the water users have to go to collect their water The walking distance for the most

distant user of a standpipe should whenever possible be limited to 200 m in sparsely populated

rural areas 500 m may be acceptable The required discharge capacity of a standpipe normally is

about 14-18 litresminute at each outlet A single-tap standpipe should preferably be used by not

more than 40-70 people a multiple-tap standpipe may provide a reasonable service for up to

250-300 persons in no case should the number of users dependent on one standpipe exceed 500

Public standpipes can operate at a low pressure Distribution systems that serve only standpipes

may therefore use low pressure piping whereas the pipes for distribution systems with house

connections generally have to be of a higher pressure class Water collected at a public standpipe

will have to be carried home in a container This means that the water that was safe at the

moment of drawing may no longer be so at the moment it is used in the house Water

consumption from standpipes generally is not higher than 20-30 litres per person per day

This consumption increases when other facilities are added to reduce the amount of water

women and children have to carry home Water use for other purposes other than drinking and

cooking is likely to be curtailed when the water has to be fetched from a standpipe

Page | 20

Yard and house connections will usually encourage a more generous water use for personal

hygiene and cleaning purposes Wastage of water from standpipes can be a serious problem

especially when users fail to turn off the taps Furthermore poor drainage of spilled water may

cause stagnant pools of dirty water with the associated health hazards It is also not uncommon

for the taps to be damaged by the users and pilferage sometimes occurs These problems occur

particularly when designs do not meet the user requirements

In spite of their shortcomings group connections and public standpipes are really the only

practical options for water distribution at minimum cost to a large number of people who cannot

afford the much higher costs of house or yard connections In fact housing is frequently not

suitably constructed to allow the installation of internal plumbing It would often be impossible

for a small community to obtain the substantial capital for a water distribution system with house

connections Also the costs of adequate disposal of the considerable amounts of wastewater

generated by a house connected water supply service would place an additional heavy financial

burden on the community Consequently public standpipes have to be provided and the principal

concern should be to lessen their inherent shortcomings as much as possible (Hofkes E H et al

1981)

261 Water Demand Variation

The daily water demand in a community area will vary during the year due to seasonal climate

patterns the work situation and other factors such as cultural or religious occasions The

maximum daily demand is usually estimated by adding 10-30 to the average daily demand

Thus the peak factor for the daily water demand (k1) is 11-13

The hourly variation in domestic water demand during the day is much greater Generally two

peak periods can be observed one in the morning and one late in the afternoon as shown in fig

28 below The peak hour demand can be expressed as the average hourly demand multiplied by

the hourly peak factor (k2) For a particular distribution area this factor depends on the size and

character of the community served The hourly peak factor tends to be high for small villages It

is usually lower for larger communities and small towns Where roof tanks or other water storage

vessels are common the hourly peak factor will be further reduced

Page | 21

Usually the factor k2 is chosen in the 15-25 range Where a pipe connection is designed to

supply a small group of consumers a higher value should be adopted because of the effects of

instantaneous demand A water distribution system is typically designed to cater for the

maximum hourly demand This peak demand may then be computed as k1 x k2 x average hourly

demand (Hofkes E H et al 1981)

Figure 28 Variation of domestic water demand during the day

262 Balancing storageWithout storage of water in the distribution area the source of supply and the water treatment

plant would have to be able to follow all fluctuations in the water demand of the community

served This is generally not economical and sometimes not even technically feasible The

design capacities of the various components of a water supply system are usually chosen as

indicated

In summary

System component Design capacity

Water source Peak day water demand

Raw water main Peak day water demand

Treatment plant Peak day water demand

Page | 22

Transmission main Peak day water demand

The service reservoir is provided to balance the (constant) supply rate from the water

sourcetreatment plant with the fluctuating water demand in the distribution area The storage

volume should be large enough to accommodate the cumulative differences between water

supply and demand (Hofkes E H et al 1981)

Figure 29 Design capacities for water supply system components

263 Distribution system design

A typical range of velocities in distribution pipes is between 05 and 10 ms occasionally up to 2

ms The hydraulic gradients usually range between 1 and 5 mkm occasionally up to 10 mkm

In case of smaller pipes D lt 50 mm the hydraulic gradient can even be higher

The pressure criterion is dependent on topographic conditions availability of water at the source

and overall condition of the pipes The minimum pressures should not drop below 5-10 meter

water column In larger distribution areas where water scarcity is not an issue the minimum

pressures can range between 20 and 30 mwc above street level where there are house

connections This is sufficient for supply of 2-3 storey buildings Pressures higher than 60 mwc

Page | 23

should be avoided in general due to increased leakage and risks of bursts especially in poorly

maintained networks

After choosing a preliminary supply scheme (gravitypumping) and type of network layout

(branchedlooped) with its main components the distribution area is divided into a number of

demand districts according to the topography land use classification and density of population

Boundaries may be drawn along rivers roads high points or other features that distinguish each

district The secondary mains and distribution pipes can then be plotted on the plan

Once all the sectors are fixed the population for each district can be estimated or computed from

data collected in the community involvement process The water demand per district is then

computed using per capita water usage figures for domestic water consumption and selected

values for the other non-domestic water requirements including productive uses This per capita

usage figure may vary depending on the water service level that the community in the concerned

district has decided on (Hofkes E H et al 1981)

264 Pipes

The water from public water supply system to individual buildings is supplied through pipes A

large proportion of capital is invested on pipes while designing water supply distribution system

The following factors should be considered in selection of pipes

Strength of pipe

Water carrying capacity

Life and durability of pipe

Expenditure on transportation

Jointing process maintenance and repairs

Several different types of pipe are used in distribution systems They all have advantages and

disadvantages related to cost installation strength and corrosion The most common types of

pipe are known by their abbreviations They include Cast Iron Pipe (CIP) Ductile Iron Pipe

(DIP) Steel Pipe (ST) Asbestos-Cement Pipe (AC) Polyvinyl Chloride Pipe (PVC) and

Unplasticised Polyvinyl Chloride Pipe (UPVC)

Page | 24

UPVC (unplasticized polyvinylchloride) pipes and fittings exhibit excellent resistance to

aggressive environments both naturally occurring and as a result of industrial activity They are

resistant to almost all types of corrosion either chemical or electrochemical in nature

Since uPVC is a non-conductor galvanic and electro chemical effects do not occur in UPVC

pipes

UPVC Pipes and fittings are often used in the following circumstances

bull For drinking water pipe distribution systems both main and supply lines

bull Sewer and discharge pipe systems

Steel pipe is lighter than iron pipe and is easier to handle and install It is more flexible than iron

pipe and doesnt require as much care when bedded in the trench The main disadvantage of steel

pipe is that it is very susceptible to corrosion and should be coated both inside and outside It

doesnt have the same bearing strength that cast or ductile iron does and may collapse under

vacuum conditions Steel pipe may be joined the same way that cast is joined It may also be

joined using threaded connections (Sacramento Water Distribution System Manual 2000)

Cast iron and ductile iron pipe are known for their strength and load bearing capacity Most of

the iron pipe that has been installed in the past 40 years is ductile iron pipe Ductile iron is

stronger and less rigid than gray cast iron pipe The main disadvantages of iron pipe are that it is

heavy and subject to corrosion from the inside and the outside It should be coated with a

corrosion resistant external coating and in certain soil conditions may require some type of

cathodic protection to achieve its normal service life

Cast and ductile iron pipes can be joined by several different means Flanged joints are used

above ground The most common means of joining them underground are the bell and spigot (O-

ring push-on) and the mechanical joint (MJ) connections Care must be taken when installing and

bedding CIP and DIP are both brittle and dont flex The bell holes should only be as wide as the

bell portion of the pipe Otherwise stresses from improper bedding can cause it to crack

(Sacramento Water Distribution System Manual 2000)

Page | 25

Page | 26

2641 Pipes Appurtenances

Valves

Valves are used to control flow in a water system Most of the valves in a distribution system are

installed for isolation of sections of piping for maintenance and repair Control valves like

pressure reducing valves altitude valves pressure relief valves pressure sustaining valves and

pump control valves are designed to control pressures and throttle flows to prevent damage to the

system Air relief valves can vent trapped air from the system Check valves allow water to flow

only in one direction

Valves may be operated by hand or by actuator Actuators generally are electric and may be

operated locally or by remote control Where there is no local power supply portable power

packs may be used

Some examples of valves include

Gate Valve - Gate valves are the most common valves in a distribution system They are used for

isolation of equipment and piping They should never be used to throttle flow This will cause

damage to the valve face Open gate valves have the less friction loss than any other type of

valve Gate valves can have plug type disks or split gates Split gates are used in higher pressure

applications

Butterfly valves - Butterfly valves serve the same purpose as gate valves These valves usually

open and close with a quarter of a turn of the valve disc Larger valves will have a gear box on

the stem and will require a number of turns to open Butterfly valves are easier to open than gate

valves usually without the need for a bypass but have more friction loss when open They can

also be used for throttling flow without damaging the disc Caution should be used when filling a

line through a butterfly valve

Air Release Valve - Air release valves are used to allow air that may be trapped in the line to

escape The trapped air can create pressure and pumping problems milky-water complaints and

pressure spikes that resemble water hammer They are very useful in systems that are in hilly

country They should be located at the top of hills where the trapped air will collect

Page | 27

They are also used on booster pumps and wells to removed trapped air Combination air release

valves will also let air in when a vacuum occurs This is done to protect the piping They can also

be used to vent a line that is being drained All air-release valves should be equipped with

isolating valves for easy removal and repair of the air valves (Sacramento Water Distribution

System Manual 2000)

Section Valves - The valves should be placed in such a way that rationing of water can be done

by closing suitable parts of the supply for certain periods Whenever possible the section valves

should be placed in a joint valve chamber with air valves or washouts and upstream of these

valves In urban areas where fire-fighting is provided for there should be an isolating valve

downstream each fire hydrant (Water Design Manual 2005 Kenya)

Valve chambers

Large valves on trunk pipelines should be located in accessible chambers to facilitate

maintenance Smaller gate valves are usually buried Valve chambers should be at least 1000 x

1000mm internally There must not be UPVC-pipes within the chamber The cover should be

lockable The chamber should be drained through the floor or through a drain pipe

Hydrants

The fire insurance rates for residents on the system will be dependent in part on the proper

spacing and discharge capabilities of the fire hydrants in the system Hydrants should not be

more than 500-600 feet apart in residential districts The spacing requirements in industrial and

rural districts may vary They should be located at the end of every dead end line Hydrants

should be operated every 6 months and flow tested annually

Fire hydrants should never be placed on less than a 6 inch line if it is to be used for fire

protection In addition to provide fire protection hydrants can also be useful for flushing lines

venting lines as they are filled and pressure and flow testing Hydrants on smaller lines (4 inch

and down) will not supply enough water to fight a fire but may be used to flush dead end lines

Page | 28

Thrust Blocks

Wherever a bend elbow tee or dead-end exists in a pipeline having flexible joints a force is

exerted which tends to open the joints nearest the fittings The magnitude of this force varies

with the amount of bend the diameter of pipe and the pressure inside the pipe When

determining the resultant thrust for a given pipe it is advisable to use the maximum working

pressure anticipated in the pipe plus an allowance for surges or water hammer

Once the resultant thrust has been determined for a particular bend it becomes necessary to

provide a backing block of such size to resist the thrust The thrust must ultimately be borne by

the side of the pipe trench and the surrounding soil The purpose of the backing block is to

spread the thrust over an area sufficiently large that the undisturbed earth can support it

2642 Washouts

A washout is seldom used for scouring or washing out a main because its diameter is too small to

create sufficient flow velocity in the main to wash out debris Its principal use is for emptying a

main or for the removal of stagnant or dirty water

Primary washouts may be installed to drain to a watercourse the majority of the length between

section valves Secondary washouts of smaller diameter can then be used to empty undrained

subsections as required Sizes particularly primary washouts need to be calculated according to

the draindown time (Twort 5th Edition)

2643 Break Pressure tanks

Static head is the difference in elevation from the source to any point on the ground profile

Static head must always be considered because excessive pressure in the pipe from the elevation

head can rapture the pipe or pipe connections Piping is rated by its ability to withstand an

internal pressure without breaking The ability is a function of the type of pipe material and

thickness of the wall pipe

Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure

that will rupture the pipe or cause failures at the joints

Page | 29

The function of a break pressure tank is to allow the flow to discharge into the atmosphere

thereby reducing its hydrostatic pressure to zero and establishing a new static level A general

rule of thumb is that the static head at any given point within the conduction line should not

exceed 100m of head There is no minimum required capacity for a break pressure tank as long

as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)

Page | 30

Chapter Three

30 METHODOLOGY

31 Introduction

Different data was needed for the design of a water supply system in Ongata Rongai Methods of

data collection were established beforehand to ensure the process was efficient Once the data

was collected it was analyzed to produce an outcome that satisfied the objective of the report

The data collected included

a) Population of the area

b) Land use

c) Topographical data

d) Existing water supply

e) Information on water consumption per capita in the area

In order to obtain this data various data collection methods were used as shown below

32 Data collection methods

Various methods were employed to collect data needed for the design of the system Both

primary and secondary data was needed The quantitative methods employed were to enable me

to obtain firsthand information needed for the project These include

a) Questionnaires

b) Interviews

c) Literature review

d) Government agencies

e) Direct observation

321 QuestionnairesQuestionnaires were prepared to aid with the collection of data The questionnaires were given to

the relevant parties In order to obtain an overview of water use in the area the questionnaire was

handed to the community for a brief description on how they use the water

Page | 31

With regards to the existing water supply it was necessary to involve Oloolaiser Water with the

use of questionnaires to obtain information on their existing system

322 InterviewsIn addition to questionnaires face to face interviews were also conducted The interviews were

done to collect data on the challenges facing the existing supply of water and the sources

available for people in the area These interviews were carried out with the members living in the

project area

Information on the proposed source was also required This particular interview was conducted

with the engineer who designed the dam itself The current population of the town and the

change of boundaries in the area over the past twenty years information was obtained from an

interview conducted with the technical manager at Oloolaiser Water and Sewerage Company

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area

323 Literature reviewDifferent reports were reviewed to get information in various areas This included the past

census reports to obtain the population of people in the area Information on land use and project

location description was also obtained from the NEMA Environmental Action plan for Kajiado

Land use data was necessary to establish where the pipeline would pass

324 Government AgenciesIn order to collect topographical data a map from the Survey of Kenya was obtained for the area

This map had information on the roads contours rivers all the natural and man-made features

which were necessary for the design of the system Information on sources of water supply in the

area was also obtained from the Oloolaiser water and sewerage company who are the water

service providers in the area

325 Direct ObservationDirect observation for information on settlement and land use was necessary because of the rate

at which the town is growing This was especially needed for the land adjacent to the road

because that was where the pipeline would pass and also to consider alternative routes for the

pipeline

Page | 32

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

a Arithmetical Increase Method

This method is suitable for large and old cities with considerable development If it is used for

small average or comparatively new cities it will give lower population estimate than actual

value In this method the average increase in population per year is calculated from the past

census reports This increase is added to the present population to find out the population of the

next year Thus it is assumed that the population is increasing at constant rate

Hence dPdt = C ie rate of change of population with respect to time is constant

Therefore Population after nth year will be Pn= P + nC

Where Pn = population after lsquonrsquo year and

P = present population

b Geometrical Progression Method

In this method the percentage increase in population from decade to decade is assumed to remain

constant Geometric mean increase is used to find out the future increment in population Since

this method gives higher values it should be applied for a new industrial town at the beginning

of development for only few years The population at the end of nth year lsquoPnrsquo can be estimated

as

Pn = P (1+ r)n

Where r = geometric mean (population growth factor in )

P = Present population

n = number of years

c Incremental Increase Method

This method is modification of arithmetical increase method and it is suitable for an average size

town under normal condition where the growth rate is found to be in increasing order While

adopting this method the increase in increment is considered for calculating future population

Page | 12

The incremental increase is determined for each year from the past population and the average

value is added to the present population along with the average rate of increase Hence

population after nth year is Pn = P+ nX + n (n+1)2Y

Where Pn = Population after nth decade

X = Average increase

Y = Incremental increase

d Graphical Method

In this method the populations of last few decades are correctly plotted to a suitable scale on

graph The population curve is smoothly extended for getting future population This extension

should be done carefully and it requires proper experience and judgment The best way of

applying this method is to extend the curve by comparing with population curve of some other

similar cities having the similar growth condition

e Comparative Graphical methods

In this method the census populations of cities already developed under similar conditions are

plotted The curve of past population of the city under consideration is plotted on the same graph

The curve is extended carefully by comparing with the population curve of some similar cities

having the similar condition of growth The advantage of this method is that the future

population can be predicted from the present population even in the absence of some of the past

census report

f Masterplan Methods

The big and metropolitan cities are generally not developed in haphazard manner but are

planned and regulated by local bodies according to master plan The master plan is prepared for

next 25 to 30 years for the city According to the master plan the city is divided into various

zones such as residence commerce and industry The population densities are fixed for various

zones in the master plan

From this population density total water demand and wastewater generation for that zone can be

worked out By this method it is very easy to access precisely the design population

Page | 13

g Logistic Curve Method

This method is used when the growth rate of population due to births deaths and migrations

takes place under normal situation and it is not subjected to any extraordinary changes like

epidemic war earth quake or any natural disaster etc and the population follows the growth

curve characteristics of living things within limited space and economic opportunity If the

population of a city is plotted with respect to time the curve so obtained under normal condition

looks like S-shaped curve and is known as logistic curve

26 Water distribution

The water distribution system or reticulation system serves to convey the water from the source

and treated when necessary to the point where it is delivered to the users For small community

water supplies the distribution system and any provision for water storage should be kept

simple Even so it may represent a substantial capital investment and the design must be done

properly

Generally the distribution system of a small community water supply is designed to cater for the

domestic and other residential water requirements Stock watering and garden irrigation may also

be provided

The water demand varies considerably in the course of a day Water consumption is highest

during the hours that water is used for personal hygiene and cleaning and when food preparation

and washing of clothes are done During the night the water use will be lowest

This variation in flow can be dealt with by operating pumps in parallel andor building balancing

storage in the system For small community water supplies the distribution system with water

storage like a service reservoir is the preferable option given that supplies of electricity or diesel

to power pumps will usually be unreliable

Service reservoirs serve to accumulate and store water during the night so that it can be supplied

during the daytime hours of high water demand

Page | 14

It is necessary to maintain a sufficient pressure in the distribution system to protect it against

contamination by the ingress of polluted seepage water A minimum pressure of 5-10m head

should be sufficient in most cases (Hofkes E H et al 1981)

Types of distribution systems

There are basically two main layouts of a distribution network

bull Branched configuration (figure 22)

bull Looped (grid) configuration (figure 22)

Branched networks are predominantly used for small-capacity community supplies delivering the

water mostly through public standpipes and having few house connections if any Although

adequate having in mind simplicity and acceptable investment costs branched networks have

some disadvantages

Low reliability which affects all users located downstream of any breakdown in the

system

Danger of contamination caused by the possibility that a large part of network will be

without water during irregular situations

Accumulation of sediments due to stagnation of the water at the system ends (ldquodeadrdquo

ends) occasionally resulting in taste and odour problems

Fluctuating water demand producing rather large pressure variations

Page | 15

Figure 22 Branched and looped distribution system

Branched systems are easy to design The direction of the water flow and the flow rates can

readily be determined for all pipes This is different in looped distribution networks where

consumers can be supplied from more than one direction Looped networks greatly improve the

hydraulics of the distribution system This is of major importance in the event that one of the

mains is out of operation for cleaning or repair

A looped network usually has a skeleton of secondary mains that can also be in a form of branch

one loop or a number of loops From there the water is conveyed towards the distribution pipes

and further to the consumers The secondary mains are connected to one or more loops or rings

The network in large (urban) distribution systems will be much more complex essentially a

combination of loops and branches with lots of interconnected pipes that requires many valves

and special parts as shown below in figure 23 To save on equipment costs over-crossing pipes

that are not interconnected may be used but at the cost of reduced reliability as shown below in

figure 24

Page | 16

Figure 23 Fully interconnected pipes

Figure 24 Overcrossing single pipes

Points at which the water is delivered to the users are called service connections The number

and type of service connections has considerable influence on the choice of a network layout

Page | 17

The following types of service connections may be distinguished

House connection

Yard connection

Group connection

Public standpipe

A house connection is a water service pipe connected with in-house plumbing to one or more

taps eg in the kitchen and bathroom Usually 38 inch (9 mm) and 12 inch (12 mm) taps are

used A typical layout is shown in figure 25

Figure 25 House connection

The service pipe is connected to the distribution main in the street by means of a T-piece on

small-diameter pipes a special insert piece or a saddle on larger-size secondary pipes A special

insert piece is mostly used for cast iron and ductile iron pipes

A yard connection is quite similar to a house connection the only difference being that the tap is

placed in the yard outside the house No in-house piping and fixtures are provided as shown

below in figure 26

Page | 18

Figure 26 Yard connection

Plastic (polyvinyl chloride or polyethylene) cast iron and galvanized steel pipes are used for

both house connections and yard connections

Group connections are outside taps that are shared by a clearly defined group of households

often neighbours Each family may pay the same (flat) share or contributions may be weighed

according to the estimated volume of water each family consumes Consumption estimates may

be based on indicators such as family size and composition and types of use by the different

households Sometimes the taps can be locked and a local committee holds the key and manages

the use and financing

Public standpipes can have one or more taps Single-tap and double-tap standpipes are the most

common types in rural areas They are made of brickwork masonry or concrete or use wooden

poles and similar materials The design should be done in close consultation with the users

(especially women) in order to arrive at an ergonomically optimal solution Standpipes may have

platforms at different levels making it easy for adults and children to use them with containers

of different sizes Examples are shown in figures 27 Cattle watering andor washing andor

bathing facilities may be constructed nearby The design and often also the construction are best

done in consultation and with participation of the user households ie both men and women

Public taps drawing from a small reservoir (cistern) represent an alternative method of water

distribution

Page | 19

Figure 27 Public Standpipes

Each standpipe should be situated at a suitable point within the community area in order to limit

the distance the water users have to go to collect their water The walking distance for the most

distant user of a standpipe should whenever possible be limited to 200 m in sparsely populated

rural areas 500 m may be acceptable The required discharge capacity of a standpipe normally is

about 14-18 litresminute at each outlet A single-tap standpipe should preferably be used by not

more than 40-70 people a multiple-tap standpipe may provide a reasonable service for up to

250-300 persons in no case should the number of users dependent on one standpipe exceed 500

Public standpipes can operate at a low pressure Distribution systems that serve only standpipes

may therefore use low pressure piping whereas the pipes for distribution systems with house

connections generally have to be of a higher pressure class Water collected at a public standpipe

will have to be carried home in a container This means that the water that was safe at the

moment of drawing may no longer be so at the moment it is used in the house Water

consumption from standpipes generally is not higher than 20-30 litres per person per day

This consumption increases when other facilities are added to reduce the amount of water

women and children have to carry home Water use for other purposes other than drinking and

cooking is likely to be curtailed when the water has to be fetched from a standpipe

Page | 20

Yard and house connections will usually encourage a more generous water use for personal

hygiene and cleaning purposes Wastage of water from standpipes can be a serious problem

especially when users fail to turn off the taps Furthermore poor drainage of spilled water may

cause stagnant pools of dirty water with the associated health hazards It is also not uncommon

for the taps to be damaged by the users and pilferage sometimes occurs These problems occur

particularly when designs do not meet the user requirements

In spite of their shortcomings group connections and public standpipes are really the only

practical options for water distribution at minimum cost to a large number of people who cannot

afford the much higher costs of house or yard connections In fact housing is frequently not

suitably constructed to allow the installation of internal plumbing It would often be impossible

for a small community to obtain the substantial capital for a water distribution system with house

connections Also the costs of adequate disposal of the considerable amounts of wastewater

generated by a house connected water supply service would place an additional heavy financial

burden on the community Consequently public standpipes have to be provided and the principal

concern should be to lessen their inherent shortcomings as much as possible (Hofkes E H et al

1981)

261 Water Demand Variation

The daily water demand in a community area will vary during the year due to seasonal climate

patterns the work situation and other factors such as cultural or religious occasions The

maximum daily demand is usually estimated by adding 10-30 to the average daily demand

Thus the peak factor for the daily water demand (k1) is 11-13

The hourly variation in domestic water demand during the day is much greater Generally two

peak periods can be observed one in the morning and one late in the afternoon as shown in fig

28 below The peak hour demand can be expressed as the average hourly demand multiplied by

the hourly peak factor (k2) For a particular distribution area this factor depends on the size and

character of the community served The hourly peak factor tends to be high for small villages It

is usually lower for larger communities and small towns Where roof tanks or other water storage

vessels are common the hourly peak factor will be further reduced

Page | 21

Usually the factor k2 is chosen in the 15-25 range Where a pipe connection is designed to

supply a small group of consumers a higher value should be adopted because of the effects of

instantaneous demand A water distribution system is typically designed to cater for the

maximum hourly demand This peak demand may then be computed as k1 x k2 x average hourly

demand (Hofkes E H et al 1981)

Figure 28 Variation of domestic water demand during the day

262 Balancing storageWithout storage of water in the distribution area the source of supply and the water treatment

plant would have to be able to follow all fluctuations in the water demand of the community

served This is generally not economical and sometimes not even technically feasible The

design capacities of the various components of a water supply system are usually chosen as

indicated

In summary

System component Design capacity

Water source Peak day water demand

Raw water main Peak day water demand

Treatment plant Peak day water demand

Page | 22

Transmission main Peak day water demand

The service reservoir is provided to balance the (constant) supply rate from the water

sourcetreatment plant with the fluctuating water demand in the distribution area The storage

volume should be large enough to accommodate the cumulative differences between water

supply and demand (Hofkes E H et al 1981)

Figure 29 Design capacities for water supply system components

263 Distribution system design

A typical range of velocities in distribution pipes is between 05 and 10 ms occasionally up to 2

ms The hydraulic gradients usually range between 1 and 5 mkm occasionally up to 10 mkm

In case of smaller pipes D lt 50 mm the hydraulic gradient can even be higher

The pressure criterion is dependent on topographic conditions availability of water at the source

and overall condition of the pipes The minimum pressures should not drop below 5-10 meter

water column In larger distribution areas where water scarcity is not an issue the minimum

pressures can range between 20 and 30 mwc above street level where there are house

connections This is sufficient for supply of 2-3 storey buildings Pressures higher than 60 mwc

Page | 23

should be avoided in general due to increased leakage and risks of bursts especially in poorly

maintained networks

After choosing a preliminary supply scheme (gravitypumping) and type of network layout

(branchedlooped) with its main components the distribution area is divided into a number of

demand districts according to the topography land use classification and density of population

Boundaries may be drawn along rivers roads high points or other features that distinguish each

district The secondary mains and distribution pipes can then be plotted on the plan

Once all the sectors are fixed the population for each district can be estimated or computed from

data collected in the community involvement process The water demand per district is then

computed using per capita water usage figures for domestic water consumption and selected

values for the other non-domestic water requirements including productive uses This per capita

usage figure may vary depending on the water service level that the community in the concerned

district has decided on (Hofkes E H et al 1981)

264 Pipes

The water from public water supply system to individual buildings is supplied through pipes A

large proportion of capital is invested on pipes while designing water supply distribution system

The following factors should be considered in selection of pipes

Strength of pipe

Water carrying capacity

Life and durability of pipe

Expenditure on transportation

Jointing process maintenance and repairs

Several different types of pipe are used in distribution systems They all have advantages and

disadvantages related to cost installation strength and corrosion The most common types of

pipe are known by their abbreviations They include Cast Iron Pipe (CIP) Ductile Iron Pipe

(DIP) Steel Pipe (ST) Asbestos-Cement Pipe (AC) Polyvinyl Chloride Pipe (PVC) and

Unplasticised Polyvinyl Chloride Pipe (UPVC)

Page | 24

UPVC (unplasticized polyvinylchloride) pipes and fittings exhibit excellent resistance to

aggressive environments both naturally occurring and as a result of industrial activity They are

resistant to almost all types of corrosion either chemical or electrochemical in nature

Since uPVC is a non-conductor galvanic and electro chemical effects do not occur in UPVC

pipes

UPVC Pipes and fittings are often used in the following circumstances

bull For drinking water pipe distribution systems both main and supply lines

bull Sewer and discharge pipe systems

Steel pipe is lighter than iron pipe and is easier to handle and install It is more flexible than iron

pipe and doesnt require as much care when bedded in the trench The main disadvantage of steel

pipe is that it is very susceptible to corrosion and should be coated both inside and outside It

doesnt have the same bearing strength that cast or ductile iron does and may collapse under

vacuum conditions Steel pipe may be joined the same way that cast is joined It may also be

joined using threaded connections (Sacramento Water Distribution System Manual 2000)

Cast iron and ductile iron pipe are known for their strength and load bearing capacity Most of

the iron pipe that has been installed in the past 40 years is ductile iron pipe Ductile iron is

stronger and less rigid than gray cast iron pipe The main disadvantages of iron pipe are that it is

heavy and subject to corrosion from the inside and the outside It should be coated with a

corrosion resistant external coating and in certain soil conditions may require some type of

cathodic protection to achieve its normal service life

Cast and ductile iron pipes can be joined by several different means Flanged joints are used

above ground The most common means of joining them underground are the bell and spigot (O-

ring push-on) and the mechanical joint (MJ) connections Care must be taken when installing and

bedding CIP and DIP are both brittle and dont flex The bell holes should only be as wide as the

bell portion of the pipe Otherwise stresses from improper bedding can cause it to crack

(Sacramento Water Distribution System Manual 2000)

Page | 25

Page | 26

2641 Pipes Appurtenances

Valves

Valves are used to control flow in a water system Most of the valves in a distribution system are

installed for isolation of sections of piping for maintenance and repair Control valves like

pressure reducing valves altitude valves pressure relief valves pressure sustaining valves and

pump control valves are designed to control pressures and throttle flows to prevent damage to the

system Air relief valves can vent trapped air from the system Check valves allow water to flow

only in one direction

Valves may be operated by hand or by actuator Actuators generally are electric and may be

operated locally or by remote control Where there is no local power supply portable power

packs may be used

Some examples of valves include

Gate Valve - Gate valves are the most common valves in a distribution system They are used for

isolation of equipment and piping They should never be used to throttle flow This will cause

damage to the valve face Open gate valves have the less friction loss than any other type of

valve Gate valves can have plug type disks or split gates Split gates are used in higher pressure

applications

Butterfly valves - Butterfly valves serve the same purpose as gate valves These valves usually

open and close with a quarter of a turn of the valve disc Larger valves will have a gear box on

the stem and will require a number of turns to open Butterfly valves are easier to open than gate

valves usually without the need for a bypass but have more friction loss when open They can

also be used for throttling flow without damaging the disc Caution should be used when filling a

line through a butterfly valve

Air Release Valve - Air release valves are used to allow air that may be trapped in the line to

escape The trapped air can create pressure and pumping problems milky-water complaints and

pressure spikes that resemble water hammer They are very useful in systems that are in hilly

country They should be located at the top of hills where the trapped air will collect

Page | 27

They are also used on booster pumps and wells to removed trapped air Combination air release

valves will also let air in when a vacuum occurs This is done to protect the piping They can also

be used to vent a line that is being drained All air-release valves should be equipped with

isolating valves for easy removal and repair of the air valves (Sacramento Water Distribution

System Manual 2000)

Section Valves - The valves should be placed in such a way that rationing of water can be done

by closing suitable parts of the supply for certain periods Whenever possible the section valves

should be placed in a joint valve chamber with air valves or washouts and upstream of these

valves In urban areas where fire-fighting is provided for there should be an isolating valve

downstream each fire hydrant (Water Design Manual 2005 Kenya)

Valve chambers

Large valves on trunk pipelines should be located in accessible chambers to facilitate

maintenance Smaller gate valves are usually buried Valve chambers should be at least 1000 x

1000mm internally There must not be UPVC-pipes within the chamber The cover should be

lockable The chamber should be drained through the floor or through a drain pipe

Hydrants

The fire insurance rates for residents on the system will be dependent in part on the proper

spacing and discharge capabilities of the fire hydrants in the system Hydrants should not be

more than 500-600 feet apart in residential districts The spacing requirements in industrial and

rural districts may vary They should be located at the end of every dead end line Hydrants

should be operated every 6 months and flow tested annually

Fire hydrants should never be placed on less than a 6 inch line if it is to be used for fire

protection In addition to provide fire protection hydrants can also be useful for flushing lines

venting lines as they are filled and pressure and flow testing Hydrants on smaller lines (4 inch

and down) will not supply enough water to fight a fire but may be used to flush dead end lines

Page | 28

Thrust Blocks

Wherever a bend elbow tee or dead-end exists in a pipeline having flexible joints a force is

exerted which tends to open the joints nearest the fittings The magnitude of this force varies

with the amount of bend the diameter of pipe and the pressure inside the pipe When

determining the resultant thrust for a given pipe it is advisable to use the maximum working

pressure anticipated in the pipe plus an allowance for surges or water hammer

Once the resultant thrust has been determined for a particular bend it becomes necessary to

provide a backing block of such size to resist the thrust The thrust must ultimately be borne by

the side of the pipe trench and the surrounding soil The purpose of the backing block is to

spread the thrust over an area sufficiently large that the undisturbed earth can support it

2642 Washouts

A washout is seldom used for scouring or washing out a main because its diameter is too small to

create sufficient flow velocity in the main to wash out debris Its principal use is for emptying a

main or for the removal of stagnant or dirty water

Primary washouts may be installed to drain to a watercourse the majority of the length between

section valves Secondary washouts of smaller diameter can then be used to empty undrained

subsections as required Sizes particularly primary washouts need to be calculated according to

the draindown time (Twort 5th Edition)

2643 Break Pressure tanks

Static head is the difference in elevation from the source to any point on the ground profile

Static head must always be considered because excessive pressure in the pipe from the elevation

head can rapture the pipe or pipe connections Piping is rated by its ability to withstand an

internal pressure without breaking The ability is a function of the type of pipe material and

thickness of the wall pipe

Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure

that will rupture the pipe or cause failures at the joints

Page | 29

The function of a break pressure tank is to allow the flow to discharge into the atmosphere

thereby reducing its hydrostatic pressure to zero and establishing a new static level A general

rule of thumb is that the static head at any given point within the conduction line should not

exceed 100m of head There is no minimum required capacity for a break pressure tank as long

as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)

Page | 30

Chapter Three

30 METHODOLOGY

31 Introduction

Different data was needed for the design of a water supply system in Ongata Rongai Methods of

data collection were established beforehand to ensure the process was efficient Once the data

was collected it was analyzed to produce an outcome that satisfied the objective of the report

The data collected included

a) Population of the area

b) Land use

c) Topographical data

d) Existing water supply

e) Information on water consumption per capita in the area

In order to obtain this data various data collection methods were used as shown below

32 Data collection methods

Various methods were employed to collect data needed for the design of the system Both

primary and secondary data was needed The quantitative methods employed were to enable me

to obtain firsthand information needed for the project These include

a) Questionnaires

b) Interviews

c) Literature review

d) Government agencies

e) Direct observation

321 QuestionnairesQuestionnaires were prepared to aid with the collection of data The questionnaires were given to

the relevant parties In order to obtain an overview of water use in the area the questionnaire was

handed to the community for a brief description on how they use the water

Page | 31

With regards to the existing water supply it was necessary to involve Oloolaiser Water with the

use of questionnaires to obtain information on their existing system

322 InterviewsIn addition to questionnaires face to face interviews were also conducted The interviews were

done to collect data on the challenges facing the existing supply of water and the sources

available for people in the area These interviews were carried out with the members living in the

project area

Information on the proposed source was also required This particular interview was conducted

with the engineer who designed the dam itself The current population of the town and the

change of boundaries in the area over the past twenty years information was obtained from an

interview conducted with the technical manager at Oloolaiser Water and Sewerage Company

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area

323 Literature reviewDifferent reports were reviewed to get information in various areas This included the past

census reports to obtain the population of people in the area Information on land use and project

location description was also obtained from the NEMA Environmental Action plan for Kajiado

Land use data was necessary to establish where the pipeline would pass

324 Government AgenciesIn order to collect topographical data a map from the Survey of Kenya was obtained for the area

This map had information on the roads contours rivers all the natural and man-made features

which were necessary for the design of the system Information on sources of water supply in the

area was also obtained from the Oloolaiser water and sewerage company who are the water

service providers in the area

325 Direct ObservationDirect observation for information on settlement and land use was necessary because of the rate

at which the town is growing This was especially needed for the land adjacent to the road

because that was where the pipeline would pass and also to consider alternative routes for the

pipeline

Page | 32

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

The incremental increase is determined for each year from the past population and the average

value is added to the present population along with the average rate of increase Hence

population after nth year is Pn = P+ nX + n (n+1)2Y

Where Pn = Population after nth decade

X = Average increase

Y = Incremental increase

d Graphical Method

In this method the populations of last few decades are correctly plotted to a suitable scale on

graph The population curve is smoothly extended for getting future population This extension

should be done carefully and it requires proper experience and judgment The best way of

applying this method is to extend the curve by comparing with population curve of some other

similar cities having the similar growth condition

e Comparative Graphical methods

In this method the census populations of cities already developed under similar conditions are

plotted The curve of past population of the city under consideration is plotted on the same graph

The curve is extended carefully by comparing with the population curve of some similar cities

having the similar condition of growth The advantage of this method is that the future

population can be predicted from the present population even in the absence of some of the past

census report

f Masterplan Methods

The big and metropolitan cities are generally not developed in haphazard manner but are

planned and regulated by local bodies according to master plan The master plan is prepared for

next 25 to 30 years for the city According to the master plan the city is divided into various

zones such as residence commerce and industry The population densities are fixed for various

zones in the master plan

From this population density total water demand and wastewater generation for that zone can be

worked out By this method it is very easy to access precisely the design population

Page | 13

g Logistic Curve Method

This method is used when the growth rate of population due to births deaths and migrations

takes place under normal situation and it is not subjected to any extraordinary changes like

epidemic war earth quake or any natural disaster etc and the population follows the growth

curve characteristics of living things within limited space and economic opportunity If the

population of a city is plotted with respect to time the curve so obtained under normal condition

looks like S-shaped curve and is known as logistic curve

26 Water distribution

The water distribution system or reticulation system serves to convey the water from the source

and treated when necessary to the point where it is delivered to the users For small community

water supplies the distribution system and any provision for water storage should be kept

simple Even so it may represent a substantial capital investment and the design must be done

properly

Generally the distribution system of a small community water supply is designed to cater for the

domestic and other residential water requirements Stock watering and garden irrigation may also

be provided

The water demand varies considerably in the course of a day Water consumption is highest

during the hours that water is used for personal hygiene and cleaning and when food preparation

and washing of clothes are done During the night the water use will be lowest

This variation in flow can be dealt with by operating pumps in parallel andor building balancing

storage in the system For small community water supplies the distribution system with water

storage like a service reservoir is the preferable option given that supplies of electricity or diesel

to power pumps will usually be unreliable

Service reservoirs serve to accumulate and store water during the night so that it can be supplied

during the daytime hours of high water demand

Page | 14

It is necessary to maintain a sufficient pressure in the distribution system to protect it against

contamination by the ingress of polluted seepage water A minimum pressure of 5-10m head

should be sufficient in most cases (Hofkes E H et al 1981)

Types of distribution systems

There are basically two main layouts of a distribution network

bull Branched configuration (figure 22)

bull Looped (grid) configuration (figure 22)

Branched networks are predominantly used for small-capacity community supplies delivering the

water mostly through public standpipes and having few house connections if any Although

adequate having in mind simplicity and acceptable investment costs branched networks have

some disadvantages

Low reliability which affects all users located downstream of any breakdown in the

system

Danger of contamination caused by the possibility that a large part of network will be

without water during irregular situations

Accumulation of sediments due to stagnation of the water at the system ends (ldquodeadrdquo

ends) occasionally resulting in taste and odour problems

Fluctuating water demand producing rather large pressure variations

Page | 15

Figure 22 Branched and looped distribution system

Branched systems are easy to design The direction of the water flow and the flow rates can

readily be determined for all pipes This is different in looped distribution networks where

consumers can be supplied from more than one direction Looped networks greatly improve the

hydraulics of the distribution system This is of major importance in the event that one of the

mains is out of operation for cleaning or repair

A looped network usually has a skeleton of secondary mains that can also be in a form of branch

one loop or a number of loops From there the water is conveyed towards the distribution pipes

and further to the consumers The secondary mains are connected to one or more loops or rings

The network in large (urban) distribution systems will be much more complex essentially a

combination of loops and branches with lots of interconnected pipes that requires many valves

and special parts as shown below in figure 23 To save on equipment costs over-crossing pipes

that are not interconnected may be used but at the cost of reduced reliability as shown below in

figure 24

Page | 16

Figure 23 Fully interconnected pipes

Figure 24 Overcrossing single pipes

Points at which the water is delivered to the users are called service connections The number

and type of service connections has considerable influence on the choice of a network layout

Page | 17

The following types of service connections may be distinguished

House connection

Yard connection

Group connection

Public standpipe

A house connection is a water service pipe connected with in-house plumbing to one or more

taps eg in the kitchen and bathroom Usually 38 inch (9 mm) and 12 inch (12 mm) taps are

used A typical layout is shown in figure 25

Figure 25 House connection

The service pipe is connected to the distribution main in the street by means of a T-piece on

small-diameter pipes a special insert piece or a saddle on larger-size secondary pipes A special

insert piece is mostly used for cast iron and ductile iron pipes

A yard connection is quite similar to a house connection the only difference being that the tap is

placed in the yard outside the house No in-house piping and fixtures are provided as shown

below in figure 26

Page | 18

Figure 26 Yard connection

Plastic (polyvinyl chloride or polyethylene) cast iron and galvanized steel pipes are used for

both house connections and yard connections

Group connections are outside taps that are shared by a clearly defined group of households

often neighbours Each family may pay the same (flat) share or contributions may be weighed

according to the estimated volume of water each family consumes Consumption estimates may

be based on indicators such as family size and composition and types of use by the different

households Sometimes the taps can be locked and a local committee holds the key and manages

the use and financing

Public standpipes can have one or more taps Single-tap and double-tap standpipes are the most

common types in rural areas They are made of brickwork masonry or concrete or use wooden

poles and similar materials The design should be done in close consultation with the users

(especially women) in order to arrive at an ergonomically optimal solution Standpipes may have

platforms at different levels making it easy for adults and children to use them with containers

of different sizes Examples are shown in figures 27 Cattle watering andor washing andor

bathing facilities may be constructed nearby The design and often also the construction are best

done in consultation and with participation of the user households ie both men and women

Public taps drawing from a small reservoir (cistern) represent an alternative method of water

distribution

Page | 19

Figure 27 Public Standpipes

Each standpipe should be situated at a suitable point within the community area in order to limit

the distance the water users have to go to collect their water The walking distance for the most

distant user of a standpipe should whenever possible be limited to 200 m in sparsely populated

rural areas 500 m may be acceptable The required discharge capacity of a standpipe normally is

about 14-18 litresminute at each outlet A single-tap standpipe should preferably be used by not

more than 40-70 people a multiple-tap standpipe may provide a reasonable service for up to

250-300 persons in no case should the number of users dependent on one standpipe exceed 500

Public standpipes can operate at a low pressure Distribution systems that serve only standpipes

may therefore use low pressure piping whereas the pipes for distribution systems with house

connections generally have to be of a higher pressure class Water collected at a public standpipe

will have to be carried home in a container This means that the water that was safe at the

moment of drawing may no longer be so at the moment it is used in the house Water

consumption from standpipes generally is not higher than 20-30 litres per person per day

This consumption increases when other facilities are added to reduce the amount of water

women and children have to carry home Water use for other purposes other than drinking and

cooking is likely to be curtailed when the water has to be fetched from a standpipe

Page | 20

Yard and house connections will usually encourage a more generous water use for personal

hygiene and cleaning purposes Wastage of water from standpipes can be a serious problem

especially when users fail to turn off the taps Furthermore poor drainage of spilled water may

cause stagnant pools of dirty water with the associated health hazards It is also not uncommon

for the taps to be damaged by the users and pilferage sometimes occurs These problems occur

particularly when designs do not meet the user requirements

In spite of their shortcomings group connections and public standpipes are really the only

practical options for water distribution at minimum cost to a large number of people who cannot

afford the much higher costs of house or yard connections In fact housing is frequently not

suitably constructed to allow the installation of internal plumbing It would often be impossible

for a small community to obtain the substantial capital for a water distribution system with house

connections Also the costs of adequate disposal of the considerable amounts of wastewater

generated by a house connected water supply service would place an additional heavy financial

burden on the community Consequently public standpipes have to be provided and the principal

concern should be to lessen their inherent shortcomings as much as possible (Hofkes E H et al

1981)

261 Water Demand Variation

The daily water demand in a community area will vary during the year due to seasonal climate

patterns the work situation and other factors such as cultural or religious occasions The

maximum daily demand is usually estimated by adding 10-30 to the average daily demand

Thus the peak factor for the daily water demand (k1) is 11-13

The hourly variation in domestic water demand during the day is much greater Generally two

peak periods can be observed one in the morning and one late in the afternoon as shown in fig

28 below The peak hour demand can be expressed as the average hourly demand multiplied by

the hourly peak factor (k2) For a particular distribution area this factor depends on the size and

character of the community served The hourly peak factor tends to be high for small villages It

is usually lower for larger communities and small towns Where roof tanks or other water storage

vessels are common the hourly peak factor will be further reduced

Page | 21

Usually the factor k2 is chosen in the 15-25 range Where a pipe connection is designed to

supply a small group of consumers a higher value should be adopted because of the effects of

instantaneous demand A water distribution system is typically designed to cater for the

maximum hourly demand This peak demand may then be computed as k1 x k2 x average hourly

demand (Hofkes E H et al 1981)

Figure 28 Variation of domestic water demand during the day

262 Balancing storageWithout storage of water in the distribution area the source of supply and the water treatment

plant would have to be able to follow all fluctuations in the water demand of the community

served This is generally not economical and sometimes not even technically feasible The

design capacities of the various components of a water supply system are usually chosen as

indicated

In summary

System component Design capacity

Water source Peak day water demand

Raw water main Peak day water demand

Treatment plant Peak day water demand

Page | 22

Transmission main Peak day water demand

The service reservoir is provided to balance the (constant) supply rate from the water

sourcetreatment plant with the fluctuating water demand in the distribution area The storage

volume should be large enough to accommodate the cumulative differences between water

supply and demand (Hofkes E H et al 1981)

Figure 29 Design capacities for water supply system components

263 Distribution system design

A typical range of velocities in distribution pipes is between 05 and 10 ms occasionally up to 2

ms The hydraulic gradients usually range between 1 and 5 mkm occasionally up to 10 mkm

In case of smaller pipes D lt 50 mm the hydraulic gradient can even be higher

The pressure criterion is dependent on topographic conditions availability of water at the source

and overall condition of the pipes The minimum pressures should not drop below 5-10 meter

water column In larger distribution areas where water scarcity is not an issue the minimum

pressures can range between 20 and 30 mwc above street level where there are house

connections This is sufficient for supply of 2-3 storey buildings Pressures higher than 60 mwc

Page | 23

should be avoided in general due to increased leakage and risks of bursts especially in poorly

maintained networks

After choosing a preliminary supply scheme (gravitypumping) and type of network layout

(branchedlooped) with its main components the distribution area is divided into a number of

demand districts according to the topography land use classification and density of population

Boundaries may be drawn along rivers roads high points or other features that distinguish each

district The secondary mains and distribution pipes can then be plotted on the plan

Once all the sectors are fixed the population for each district can be estimated or computed from

data collected in the community involvement process The water demand per district is then

computed using per capita water usage figures for domestic water consumption and selected

values for the other non-domestic water requirements including productive uses This per capita

usage figure may vary depending on the water service level that the community in the concerned

district has decided on (Hofkes E H et al 1981)

264 Pipes

The water from public water supply system to individual buildings is supplied through pipes A

large proportion of capital is invested on pipes while designing water supply distribution system

The following factors should be considered in selection of pipes

Strength of pipe

Water carrying capacity

Life and durability of pipe

Expenditure on transportation

Jointing process maintenance and repairs

Several different types of pipe are used in distribution systems They all have advantages and

disadvantages related to cost installation strength and corrosion The most common types of

pipe are known by their abbreviations They include Cast Iron Pipe (CIP) Ductile Iron Pipe

(DIP) Steel Pipe (ST) Asbestos-Cement Pipe (AC) Polyvinyl Chloride Pipe (PVC) and

Unplasticised Polyvinyl Chloride Pipe (UPVC)

Page | 24

UPVC (unplasticized polyvinylchloride) pipes and fittings exhibit excellent resistance to

aggressive environments both naturally occurring and as a result of industrial activity They are

resistant to almost all types of corrosion either chemical or electrochemical in nature

Since uPVC is a non-conductor galvanic and electro chemical effects do not occur in UPVC

pipes

UPVC Pipes and fittings are often used in the following circumstances

bull For drinking water pipe distribution systems both main and supply lines

bull Sewer and discharge pipe systems

Steel pipe is lighter than iron pipe and is easier to handle and install It is more flexible than iron

pipe and doesnt require as much care when bedded in the trench The main disadvantage of steel

pipe is that it is very susceptible to corrosion and should be coated both inside and outside It

doesnt have the same bearing strength that cast or ductile iron does and may collapse under

vacuum conditions Steel pipe may be joined the same way that cast is joined It may also be

joined using threaded connections (Sacramento Water Distribution System Manual 2000)

Cast iron and ductile iron pipe are known for their strength and load bearing capacity Most of

the iron pipe that has been installed in the past 40 years is ductile iron pipe Ductile iron is

stronger and less rigid than gray cast iron pipe The main disadvantages of iron pipe are that it is

heavy and subject to corrosion from the inside and the outside It should be coated with a

corrosion resistant external coating and in certain soil conditions may require some type of

cathodic protection to achieve its normal service life

Cast and ductile iron pipes can be joined by several different means Flanged joints are used

above ground The most common means of joining them underground are the bell and spigot (O-

ring push-on) and the mechanical joint (MJ) connections Care must be taken when installing and

bedding CIP and DIP are both brittle and dont flex The bell holes should only be as wide as the

bell portion of the pipe Otherwise stresses from improper bedding can cause it to crack

(Sacramento Water Distribution System Manual 2000)

Page | 25

Page | 26

2641 Pipes Appurtenances

Valves

Valves are used to control flow in a water system Most of the valves in a distribution system are

installed for isolation of sections of piping for maintenance and repair Control valves like

pressure reducing valves altitude valves pressure relief valves pressure sustaining valves and

pump control valves are designed to control pressures and throttle flows to prevent damage to the

system Air relief valves can vent trapped air from the system Check valves allow water to flow

only in one direction

Valves may be operated by hand or by actuator Actuators generally are electric and may be

operated locally or by remote control Where there is no local power supply portable power

packs may be used

Some examples of valves include

Gate Valve - Gate valves are the most common valves in a distribution system They are used for

isolation of equipment and piping They should never be used to throttle flow This will cause

damage to the valve face Open gate valves have the less friction loss than any other type of

valve Gate valves can have plug type disks or split gates Split gates are used in higher pressure

applications

Butterfly valves - Butterfly valves serve the same purpose as gate valves These valves usually

open and close with a quarter of a turn of the valve disc Larger valves will have a gear box on

the stem and will require a number of turns to open Butterfly valves are easier to open than gate

valves usually without the need for a bypass but have more friction loss when open They can

also be used for throttling flow without damaging the disc Caution should be used when filling a

line through a butterfly valve

Air Release Valve - Air release valves are used to allow air that may be trapped in the line to

escape The trapped air can create pressure and pumping problems milky-water complaints and

pressure spikes that resemble water hammer They are very useful in systems that are in hilly

country They should be located at the top of hills where the trapped air will collect

Page | 27

They are also used on booster pumps and wells to removed trapped air Combination air release

valves will also let air in when a vacuum occurs This is done to protect the piping They can also

be used to vent a line that is being drained All air-release valves should be equipped with

isolating valves for easy removal and repair of the air valves (Sacramento Water Distribution

System Manual 2000)

Section Valves - The valves should be placed in such a way that rationing of water can be done

by closing suitable parts of the supply for certain periods Whenever possible the section valves

should be placed in a joint valve chamber with air valves or washouts and upstream of these

valves In urban areas where fire-fighting is provided for there should be an isolating valve

downstream each fire hydrant (Water Design Manual 2005 Kenya)

Valve chambers

Large valves on trunk pipelines should be located in accessible chambers to facilitate

maintenance Smaller gate valves are usually buried Valve chambers should be at least 1000 x

1000mm internally There must not be UPVC-pipes within the chamber The cover should be

lockable The chamber should be drained through the floor or through a drain pipe

Hydrants

The fire insurance rates for residents on the system will be dependent in part on the proper

spacing and discharge capabilities of the fire hydrants in the system Hydrants should not be

more than 500-600 feet apart in residential districts The spacing requirements in industrial and

rural districts may vary They should be located at the end of every dead end line Hydrants

should be operated every 6 months and flow tested annually

Fire hydrants should never be placed on less than a 6 inch line if it is to be used for fire

protection In addition to provide fire protection hydrants can also be useful for flushing lines

venting lines as they are filled and pressure and flow testing Hydrants on smaller lines (4 inch

and down) will not supply enough water to fight a fire but may be used to flush dead end lines

Page | 28

Thrust Blocks

Wherever a bend elbow tee or dead-end exists in a pipeline having flexible joints a force is

exerted which tends to open the joints nearest the fittings The magnitude of this force varies

with the amount of bend the diameter of pipe and the pressure inside the pipe When

determining the resultant thrust for a given pipe it is advisable to use the maximum working

pressure anticipated in the pipe plus an allowance for surges or water hammer

Once the resultant thrust has been determined for a particular bend it becomes necessary to

provide a backing block of such size to resist the thrust The thrust must ultimately be borne by

the side of the pipe trench and the surrounding soil The purpose of the backing block is to

spread the thrust over an area sufficiently large that the undisturbed earth can support it

2642 Washouts

A washout is seldom used for scouring or washing out a main because its diameter is too small to

create sufficient flow velocity in the main to wash out debris Its principal use is for emptying a

main or for the removal of stagnant or dirty water

Primary washouts may be installed to drain to a watercourse the majority of the length between

section valves Secondary washouts of smaller diameter can then be used to empty undrained

subsections as required Sizes particularly primary washouts need to be calculated according to

the draindown time (Twort 5th Edition)

2643 Break Pressure tanks

Static head is the difference in elevation from the source to any point on the ground profile

Static head must always be considered because excessive pressure in the pipe from the elevation

head can rapture the pipe or pipe connections Piping is rated by its ability to withstand an

internal pressure without breaking The ability is a function of the type of pipe material and

thickness of the wall pipe

Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure

that will rupture the pipe or cause failures at the joints

Page | 29

The function of a break pressure tank is to allow the flow to discharge into the atmosphere

thereby reducing its hydrostatic pressure to zero and establishing a new static level A general

rule of thumb is that the static head at any given point within the conduction line should not

exceed 100m of head There is no minimum required capacity for a break pressure tank as long

as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)

Page | 30

Chapter Three

30 METHODOLOGY

31 Introduction

Different data was needed for the design of a water supply system in Ongata Rongai Methods of

data collection were established beforehand to ensure the process was efficient Once the data

was collected it was analyzed to produce an outcome that satisfied the objective of the report

The data collected included

a) Population of the area

b) Land use

c) Topographical data

d) Existing water supply

e) Information on water consumption per capita in the area

In order to obtain this data various data collection methods were used as shown below

32 Data collection methods

Various methods were employed to collect data needed for the design of the system Both

primary and secondary data was needed The quantitative methods employed were to enable me

to obtain firsthand information needed for the project These include

a) Questionnaires

b) Interviews

c) Literature review

d) Government agencies

e) Direct observation

321 QuestionnairesQuestionnaires were prepared to aid with the collection of data The questionnaires were given to

the relevant parties In order to obtain an overview of water use in the area the questionnaire was

handed to the community for a brief description on how they use the water

Page | 31

With regards to the existing water supply it was necessary to involve Oloolaiser Water with the

use of questionnaires to obtain information on their existing system

322 InterviewsIn addition to questionnaires face to face interviews were also conducted The interviews were

done to collect data on the challenges facing the existing supply of water and the sources

available for people in the area These interviews were carried out with the members living in the

project area

Information on the proposed source was also required This particular interview was conducted

with the engineer who designed the dam itself The current population of the town and the

change of boundaries in the area over the past twenty years information was obtained from an

interview conducted with the technical manager at Oloolaiser Water and Sewerage Company

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area

323 Literature reviewDifferent reports were reviewed to get information in various areas This included the past

census reports to obtain the population of people in the area Information on land use and project

location description was also obtained from the NEMA Environmental Action plan for Kajiado

Land use data was necessary to establish where the pipeline would pass

324 Government AgenciesIn order to collect topographical data a map from the Survey of Kenya was obtained for the area

This map had information on the roads contours rivers all the natural and man-made features

which were necessary for the design of the system Information on sources of water supply in the

area was also obtained from the Oloolaiser water and sewerage company who are the water

service providers in the area

325 Direct ObservationDirect observation for information on settlement and land use was necessary because of the rate

at which the town is growing This was especially needed for the land adjacent to the road

because that was where the pipeline would pass and also to consider alternative routes for the

pipeline

Page | 32

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

g Logistic Curve Method

This method is used when the growth rate of population due to births deaths and migrations

takes place under normal situation and it is not subjected to any extraordinary changes like

epidemic war earth quake or any natural disaster etc and the population follows the growth

curve characteristics of living things within limited space and economic opportunity If the

population of a city is plotted with respect to time the curve so obtained under normal condition

looks like S-shaped curve and is known as logistic curve

26 Water distribution

The water distribution system or reticulation system serves to convey the water from the source

and treated when necessary to the point where it is delivered to the users For small community

water supplies the distribution system and any provision for water storage should be kept

simple Even so it may represent a substantial capital investment and the design must be done

properly

Generally the distribution system of a small community water supply is designed to cater for the

domestic and other residential water requirements Stock watering and garden irrigation may also

be provided

The water demand varies considerably in the course of a day Water consumption is highest

during the hours that water is used for personal hygiene and cleaning and when food preparation

and washing of clothes are done During the night the water use will be lowest

This variation in flow can be dealt with by operating pumps in parallel andor building balancing

storage in the system For small community water supplies the distribution system with water

storage like a service reservoir is the preferable option given that supplies of electricity or diesel

to power pumps will usually be unreliable

Service reservoirs serve to accumulate and store water during the night so that it can be supplied

during the daytime hours of high water demand

Page | 14

It is necessary to maintain a sufficient pressure in the distribution system to protect it against

contamination by the ingress of polluted seepage water A minimum pressure of 5-10m head

should be sufficient in most cases (Hofkes E H et al 1981)

Types of distribution systems

There are basically two main layouts of a distribution network

bull Branched configuration (figure 22)

bull Looped (grid) configuration (figure 22)

Branched networks are predominantly used for small-capacity community supplies delivering the

water mostly through public standpipes and having few house connections if any Although

adequate having in mind simplicity and acceptable investment costs branched networks have

some disadvantages

Low reliability which affects all users located downstream of any breakdown in the

system

Danger of contamination caused by the possibility that a large part of network will be

without water during irregular situations

Accumulation of sediments due to stagnation of the water at the system ends (ldquodeadrdquo

ends) occasionally resulting in taste and odour problems

Fluctuating water demand producing rather large pressure variations

Page | 15

Figure 22 Branched and looped distribution system

Branched systems are easy to design The direction of the water flow and the flow rates can

readily be determined for all pipes This is different in looped distribution networks where

consumers can be supplied from more than one direction Looped networks greatly improve the

hydraulics of the distribution system This is of major importance in the event that one of the

mains is out of operation for cleaning or repair

A looped network usually has a skeleton of secondary mains that can also be in a form of branch

one loop or a number of loops From there the water is conveyed towards the distribution pipes

and further to the consumers The secondary mains are connected to one or more loops or rings

The network in large (urban) distribution systems will be much more complex essentially a

combination of loops and branches with lots of interconnected pipes that requires many valves

and special parts as shown below in figure 23 To save on equipment costs over-crossing pipes

that are not interconnected may be used but at the cost of reduced reliability as shown below in

figure 24

Page | 16

Figure 23 Fully interconnected pipes

Figure 24 Overcrossing single pipes

Points at which the water is delivered to the users are called service connections The number

and type of service connections has considerable influence on the choice of a network layout

Page | 17

The following types of service connections may be distinguished

House connection

Yard connection

Group connection

Public standpipe

A house connection is a water service pipe connected with in-house plumbing to one or more

taps eg in the kitchen and bathroom Usually 38 inch (9 mm) and 12 inch (12 mm) taps are

used A typical layout is shown in figure 25

Figure 25 House connection

The service pipe is connected to the distribution main in the street by means of a T-piece on

small-diameter pipes a special insert piece or a saddle on larger-size secondary pipes A special

insert piece is mostly used for cast iron and ductile iron pipes

A yard connection is quite similar to a house connection the only difference being that the tap is

placed in the yard outside the house No in-house piping and fixtures are provided as shown

below in figure 26

Page | 18

Figure 26 Yard connection

Plastic (polyvinyl chloride or polyethylene) cast iron and galvanized steel pipes are used for

both house connections and yard connections

Group connections are outside taps that are shared by a clearly defined group of households

often neighbours Each family may pay the same (flat) share or contributions may be weighed

according to the estimated volume of water each family consumes Consumption estimates may

be based on indicators such as family size and composition and types of use by the different

households Sometimes the taps can be locked and a local committee holds the key and manages

the use and financing

Public standpipes can have one or more taps Single-tap and double-tap standpipes are the most

common types in rural areas They are made of brickwork masonry or concrete or use wooden

poles and similar materials The design should be done in close consultation with the users

(especially women) in order to arrive at an ergonomically optimal solution Standpipes may have

platforms at different levels making it easy for adults and children to use them with containers

of different sizes Examples are shown in figures 27 Cattle watering andor washing andor

bathing facilities may be constructed nearby The design and often also the construction are best

done in consultation and with participation of the user households ie both men and women

Public taps drawing from a small reservoir (cistern) represent an alternative method of water

distribution

Page | 19

Figure 27 Public Standpipes

Each standpipe should be situated at a suitable point within the community area in order to limit

the distance the water users have to go to collect their water The walking distance for the most

distant user of a standpipe should whenever possible be limited to 200 m in sparsely populated

rural areas 500 m may be acceptable The required discharge capacity of a standpipe normally is

about 14-18 litresminute at each outlet A single-tap standpipe should preferably be used by not

more than 40-70 people a multiple-tap standpipe may provide a reasonable service for up to

250-300 persons in no case should the number of users dependent on one standpipe exceed 500

Public standpipes can operate at a low pressure Distribution systems that serve only standpipes

may therefore use low pressure piping whereas the pipes for distribution systems with house

connections generally have to be of a higher pressure class Water collected at a public standpipe

will have to be carried home in a container This means that the water that was safe at the

moment of drawing may no longer be so at the moment it is used in the house Water

consumption from standpipes generally is not higher than 20-30 litres per person per day

This consumption increases when other facilities are added to reduce the amount of water

women and children have to carry home Water use for other purposes other than drinking and

cooking is likely to be curtailed when the water has to be fetched from a standpipe

Page | 20

Yard and house connections will usually encourage a more generous water use for personal

hygiene and cleaning purposes Wastage of water from standpipes can be a serious problem

especially when users fail to turn off the taps Furthermore poor drainage of spilled water may

cause stagnant pools of dirty water with the associated health hazards It is also not uncommon

for the taps to be damaged by the users and pilferage sometimes occurs These problems occur

particularly when designs do not meet the user requirements

In spite of their shortcomings group connections and public standpipes are really the only

practical options for water distribution at minimum cost to a large number of people who cannot

afford the much higher costs of house or yard connections In fact housing is frequently not

suitably constructed to allow the installation of internal plumbing It would often be impossible

for a small community to obtain the substantial capital for a water distribution system with house

connections Also the costs of adequate disposal of the considerable amounts of wastewater

generated by a house connected water supply service would place an additional heavy financial

burden on the community Consequently public standpipes have to be provided and the principal

concern should be to lessen their inherent shortcomings as much as possible (Hofkes E H et al

1981)

261 Water Demand Variation

The daily water demand in a community area will vary during the year due to seasonal climate

patterns the work situation and other factors such as cultural or religious occasions The

maximum daily demand is usually estimated by adding 10-30 to the average daily demand

Thus the peak factor for the daily water demand (k1) is 11-13

The hourly variation in domestic water demand during the day is much greater Generally two

peak periods can be observed one in the morning and one late in the afternoon as shown in fig

28 below The peak hour demand can be expressed as the average hourly demand multiplied by

the hourly peak factor (k2) For a particular distribution area this factor depends on the size and

character of the community served The hourly peak factor tends to be high for small villages It

is usually lower for larger communities and small towns Where roof tanks or other water storage

vessels are common the hourly peak factor will be further reduced

Page | 21

Usually the factor k2 is chosen in the 15-25 range Where a pipe connection is designed to

supply a small group of consumers a higher value should be adopted because of the effects of

instantaneous demand A water distribution system is typically designed to cater for the

maximum hourly demand This peak demand may then be computed as k1 x k2 x average hourly

demand (Hofkes E H et al 1981)

Figure 28 Variation of domestic water demand during the day

262 Balancing storageWithout storage of water in the distribution area the source of supply and the water treatment

plant would have to be able to follow all fluctuations in the water demand of the community

served This is generally not economical and sometimes not even technically feasible The

design capacities of the various components of a water supply system are usually chosen as

indicated

In summary

System component Design capacity

Water source Peak day water demand

Raw water main Peak day water demand

Treatment plant Peak day water demand

Page | 22

Transmission main Peak day water demand

The service reservoir is provided to balance the (constant) supply rate from the water

sourcetreatment plant with the fluctuating water demand in the distribution area The storage

volume should be large enough to accommodate the cumulative differences between water

supply and demand (Hofkes E H et al 1981)

Figure 29 Design capacities for water supply system components

263 Distribution system design

A typical range of velocities in distribution pipes is between 05 and 10 ms occasionally up to 2

ms The hydraulic gradients usually range between 1 and 5 mkm occasionally up to 10 mkm

In case of smaller pipes D lt 50 mm the hydraulic gradient can even be higher

The pressure criterion is dependent on topographic conditions availability of water at the source

and overall condition of the pipes The minimum pressures should not drop below 5-10 meter

water column In larger distribution areas where water scarcity is not an issue the minimum

pressures can range between 20 and 30 mwc above street level where there are house

connections This is sufficient for supply of 2-3 storey buildings Pressures higher than 60 mwc

Page | 23

should be avoided in general due to increased leakage and risks of bursts especially in poorly

maintained networks

After choosing a preliminary supply scheme (gravitypumping) and type of network layout

(branchedlooped) with its main components the distribution area is divided into a number of

demand districts according to the topography land use classification and density of population

Boundaries may be drawn along rivers roads high points or other features that distinguish each

district The secondary mains and distribution pipes can then be plotted on the plan

Once all the sectors are fixed the population for each district can be estimated or computed from

data collected in the community involvement process The water demand per district is then

computed using per capita water usage figures for domestic water consumption and selected

values for the other non-domestic water requirements including productive uses This per capita

usage figure may vary depending on the water service level that the community in the concerned

district has decided on (Hofkes E H et al 1981)

264 Pipes

The water from public water supply system to individual buildings is supplied through pipes A

large proportion of capital is invested on pipes while designing water supply distribution system

The following factors should be considered in selection of pipes

Strength of pipe

Water carrying capacity

Life and durability of pipe

Expenditure on transportation

Jointing process maintenance and repairs

Several different types of pipe are used in distribution systems They all have advantages and

disadvantages related to cost installation strength and corrosion The most common types of

pipe are known by their abbreviations They include Cast Iron Pipe (CIP) Ductile Iron Pipe

(DIP) Steel Pipe (ST) Asbestos-Cement Pipe (AC) Polyvinyl Chloride Pipe (PVC) and

Unplasticised Polyvinyl Chloride Pipe (UPVC)

Page | 24

UPVC (unplasticized polyvinylchloride) pipes and fittings exhibit excellent resistance to

aggressive environments both naturally occurring and as a result of industrial activity They are

resistant to almost all types of corrosion either chemical or electrochemical in nature

Since uPVC is a non-conductor galvanic and electro chemical effects do not occur in UPVC

pipes

UPVC Pipes and fittings are often used in the following circumstances

bull For drinking water pipe distribution systems both main and supply lines

bull Sewer and discharge pipe systems

Steel pipe is lighter than iron pipe and is easier to handle and install It is more flexible than iron

pipe and doesnt require as much care when bedded in the trench The main disadvantage of steel

pipe is that it is very susceptible to corrosion and should be coated both inside and outside It

doesnt have the same bearing strength that cast or ductile iron does and may collapse under

vacuum conditions Steel pipe may be joined the same way that cast is joined It may also be

joined using threaded connections (Sacramento Water Distribution System Manual 2000)

Cast iron and ductile iron pipe are known for their strength and load bearing capacity Most of

the iron pipe that has been installed in the past 40 years is ductile iron pipe Ductile iron is

stronger and less rigid than gray cast iron pipe The main disadvantages of iron pipe are that it is

heavy and subject to corrosion from the inside and the outside It should be coated with a

corrosion resistant external coating and in certain soil conditions may require some type of

cathodic protection to achieve its normal service life

Cast and ductile iron pipes can be joined by several different means Flanged joints are used

above ground The most common means of joining them underground are the bell and spigot (O-

ring push-on) and the mechanical joint (MJ) connections Care must be taken when installing and

bedding CIP and DIP are both brittle and dont flex The bell holes should only be as wide as the

bell portion of the pipe Otherwise stresses from improper bedding can cause it to crack

(Sacramento Water Distribution System Manual 2000)

Page | 25

Page | 26

2641 Pipes Appurtenances

Valves

Valves are used to control flow in a water system Most of the valves in a distribution system are

installed for isolation of sections of piping for maintenance and repair Control valves like

pressure reducing valves altitude valves pressure relief valves pressure sustaining valves and

pump control valves are designed to control pressures and throttle flows to prevent damage to the

system Air relief valves can vent trapped air from the system Check valves allow water to flow

only in one direction

Valves may be operated by hand or by actuator Actuators generally are electric and may be

operated locally or by remote control Where there is no local power supply portable power

packs may be used

Some examples of valves include

Gate Valve - Gate valves are the most common valves in a distribution system They are used for

isolation of equipment and piping They should never be used to throttle flow This will cause

damage to the valve face Open gate valves have the less friction loss than any other type of

valve Gate valves can have plug type disks or split gates Split gates are used in higher pressure

applications

Butterfly valves - Butterfly valves serve the same purpose as gate valves These valves usually

open and close with a quarter of a turn of the valve disc Larger valves will have a gear box on

the stem and will require a number of turns to open Butterfly valves are easier to open than gate

valves usually without the need for a bypass but have more friction loss when open They can

also be used for throttling flow without damaging the disc Caution should be used when filling a

line through a butterfly valve

Air Release Valve - Air release valves are used to allow air that may be trapped in the line to

escape The trapped air can create pressure and pumping problems milky-water complaints and

pressure spikes that resemble water hammer They are very useful in systems that are in hilly

country They should be located at the top of hills where the trapped air will collect

Page | 27

They are also used on booster pumps and wells to removed trapped air Combination air release

valves will also let air in when a vacuum occurs This is done to protect the piping They can also

be used to vent a line that is being drained All air-release valves should be equipped with

isolating valves for easy removal and repair of the air valves (Sacramento Water Distribution

System Manual 2000)

Section Valves - The valves should be placed in such a way that rationing of water can be done

by closing suitable parts of the supply for certain periods Whenever possible the section valves

should be placed in a joint valve chamber with air valves or washouts and upstream of these

valves In urban areas where fire-fighting is provided for there should be an isolating valve

downstream each fire hydrant (Water Design Manual 2005 Kenya)

Valve chambers

Large valves on trunk pipelines should be located in accessible chambers to facilitate

maintenance Smaller gate valves are usually buried Valve chambers should be at least 1000 x

1000mm internally There must not be UPVC-pipes within the chamber The cover should be

lockable The chamber should be drained through the floor or through a drain pipe

Hydrants

The fire insurance rates for residents on the system will be dependent in part on the proper

spacing and discharge capabilities of the fire hydrants in the system Hydrants should not be

more than 500-600 feet apart in residential districts The spacing requirements in industrial and

rural districts may vary They should be located at the end of every dead end line Hydrants

should be operated every 6 months and flow tested annually

Fire hydrants should never be placed on less than a 6 inch line if it is to be used for fire

protection In addition to provide fire protection hydrants can also be useful for flushing lines

venting lines as they are filled and pressure and flow testing Hydrants on smaller lines (4 inch

and down) will not supply enough water to fight a fire but may be used to flush dead end lines

Page | 28

Thrust Blocks

Wherever a bend elbow tee or dead-end exists in a pipeline having flexible joints a force is

exerted which tends to open the joints nearest the fittings The magnitude of this force varies

with the amount of bend the diameter of pipe and the pressure inside the pipe When

determining the resultant thrust for a given pipe it is advisable to use the maximum working

pressure anticipated in the pipe plus an allowance for surges or water hammer

Once the resultant thrust has been determined for a particular bend it becomes necessary to

provide a backing block of such size to resist the thrust The thrust must ultimately be borne by

the side of the pipe trench and the surrounding soil The purpose of the backing block is to

spread the thrust over an area sufficiently large that the undisturbed earth can support it

2642 Washouts

A washout is seldom used for scouring or washing out a main because its diameter is too small to

create sufficient flow velocity in the main to wash out debris Its principal use is for emptying a

main or for the removal of stagnant or dirty water

Primary washouts may be installed to drain to a watercourse the majority of the length between

section valves Secondary washouts of smaller diameter can then be used to empty undrained

subsections as required Sizes particularly primary washouts need to be calculated according to

the draindown time (Twort 5th Edition)

2643 Break Pressure tanks

Static head is the difference in elevation from the source to any point on the ground profile

Static head must always be considered because excessive pressure in the pipe from the elevation

head can rapture the pipe or pipe connections Piping is rated by its ability to withstand an

internal pressure without breaking The ability is a function of the type of pipe material and

thickness of the wall pipe

Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure

that will rupture the pipe or cause failures at the joints

Page | 29

The function of a break pressure tank is to allow the flow to discharge into the atmosphere

thereby reducing its hydrostatic pressure to zero and establishing a new static level A general

rule of thumb is that the static head at any given point within the conduction line should not

exceed 100m of head There is no minimum required capacity for a break pressure tank as long

as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)

Page | 30

Chapter Three

30 METHODOLOGY

31 Introduction

Different data was needed for the design of a water supply system in Ongata Rongai Methods of

data collection were established beforehand to ensure the process was efficient Once the data

was collected it was analyzed to produce an outcome that satisfied the objective of the report

The data collected included

a) Population of the area

b) Land use

c) Topographical data

d) Existing water supply

e) Information on water consumption per capita in the area

In order to obtain this data various data collection methods were used as shown below

32 Data collection methods

Various methods were employed to collect data needed for the design of the system Both

primary and secondary data was needed The quantitative methods employed were to enable me

to obtain firsthand information needed for the project These include

a) Questionnaires

b) Interviews

c) Literature review

d) Government agencies

e) Direct observation

321 QuestionnairesQuestionnaires were prepared to aid with the collection of data The questionnaires were given to

the relevant parties In order to obtain an overview of water use in the area the questionnaire was

handed to the community for a brief description on how they use the water

Page | 31

With regards to the existing water supply it was necessary to involve Oloolaiser Water with the

use of questionnaires to obtain information on their existing system

322 InterviewsIn addition to questionnaires face to face interviews were also conducted The interviews were

done to collect data on the challenges facing the existing supply of water and the sources

available for people in the area These interviews were carried out with the members living in the

project area

Information on the proposed source was also required This particular interview was conducted

with the engineer who designed the dam itself The current population of the town and the

change of boundaries in the area over the past twenty years information was obtained from an

interview conducted with the technical manager at Oloolaiser Water and Sewerage Company

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area

323 Literature reviewDifferent reports were reviewed to get information in various areas This included the past

census reports to obtain the population of people in the area Information on land use and project

location description was also obtained from the NEMA Environmental Action plan for Kajiado

Land use data was necessary to establish where the pipeline would pass

324 Government AgenciesIn order to collect topographical data a map from the Survey of Kenya was obtained for the area

This map had information on the roads contours rivers all the natural and man-made features

which were necessary for the design of the system Information on sources of water supply in the

area was also obtained from the Oloolaiser water and sewerage company who are the water

service providers in the area

325 Direct ObservationDirect observation for information on settlement and land use was necessary because of the rate

at which the town is growing This was especially needed for the land adjacent to the road

because that was where the pipeline would pass and also to consider alternative routes for the

pipeline

Page | 32

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

It is necessary to maintain a sufficient pressure in the distribution system to protect it against

contamination by the ingress of polluted seepage water A minimum pressure of 5-10m head

should be sufficient in most cases (Hofkes E H et al 1981)

Types of distribution systems

There are basically two main layouts of a distribution network

bull Branched configuration (figure 22)

bull Looped (grid) configuration (figure 22)

Branched networks are predominantly used for small-capacity community supplies delivering the

water mostly through public standpipes and having few house connections if any Although

adequate having in mind simplicity and acceptable investment costs branched networks have

some disadvantages

Low reliability which affects all users located downstream of any breakdown in the

system

Danger of contamination caused by the possibility that a large part of network will be

without water during irregular situations

Accumulation of sediments due to stagnation of the water at the system ends (ldquodeadrdquo

ends) occasionally resulting in taste and odour problems

Fluctuating water demand producing rather large pressure variations

Page | 15

Figure 22 Branched and looped distribution system

Branched systems are easy to design The direction of the water flow and the flow rates can

readily be determined for all pipes This is different in looped distribution networks where

consumers can be supplied from more than one direction Looped networks greatly improve the

hydraulics of the distribution system This is of major importance in the event that one of the

mains is out of operation for cleaning or repair

A looped network usually has a skeleton of secondary mains that can also be in a form of branch

one loop or a number of loops From there the water is conveyed towards the distribution pipes

and further to the consumers The secondary mains are connected to one or more loops or rings

The network in large (urban) distribution systems will be much more complex essentially a

combination of loops and branches with lots of interconnected pipes that requires many valves

and special parts as shown below in figure 23 To save on equipment costs over-crossing pipes

that are not interconnected may be used but at the cost of reduced reliability as shown below in

figure 24

Page | 16

Figure 23 Fully interconnected pipes

Figure 24 Overcrossing single pipes

Points at which the water is delivered to the users are called service connections The number

and type of service connections has considerable influence on the choice of a network layout

Page | 17

The following types of service connections may be distinguished

House connection

Yard connection

Group connection

Public standpipe

A house connection is a water service pipe connected with in-house plumbing to one or more

taps eg in the kitchen and bathroom Usually 38 inch (9 mm) and 12 inch (12 mm) taps are

used A typical layout is shown in figure 25

Figure 25 House connection

The service pipe is connected to the distribution main in the street by means of a T-piece on

small-diameter pipes a special insert piece or a saddle on larger-size secondary pipes A special

insert piece is mostly used for cast iron and ductile iron pipes

A yard connection is quite similar to a house connection the only difference being that the tap is

placed in the yard outside the house No in-house piping and fixtures are provided as shown

below in figure 26

Page | 18

Figure 26 Yard connection

Plastic (polyvinyl chloride or polyethylene) cast iron and galvanized steel pipes are used for

both house connections and yard connections

Group connections are outside taps that are shared by a clearly defined group of households

often neighbours Each family may pay the same (flat) share or contributions may be weighed

according to the estimated volume of water each family consumes Consumption estimates may

be based on indicators such as family size and composition and types of use by the different

households Sometimes the taps can be locked and a local committee holds the key and manages

the use and financing

Public standpipes can have one or more taps Single-tap and double-tap standpipes are the most

common types in rural areas They are made of brickwork masonry or concrete or use wooden

poles and similar materials The design should be done in close consultation with the users

(especially women) in order to arrive at an ergonomically optimal solution Standpipes may have

platforms at different levels making it easy for adults and children to use them with containers

of different sizes Examples are shown in figures 27 Cattle watering andor washing andor

bathing facilities may be constructed nearby The design and often also the construction are best

done in consultation and with participation of the user households ie both men and women

Public taps drawing from a small reservoir (cistern) represent an alternative method of water

distribution

Page | 19

Figure 27 Public Standpipes

Each standpipe should be situated at a suitable point within the community area in order to limit

the distance the water users have to go to collect their water The walking distance for the most

distant user of a standpipe should whenever possible be limited to 200 m in sparsely populated

rural areas 500 m may be acceptable The required discharge capacity of a standpipe normally is

about 14-18 litresminute at each outlet A single-tap standpipe should preferably be used by not

more than 40-70 people a multiple-tap standpipe may provide a reasonable service for up to

250-300 persons in no case should the number of users dependent on one standpipe exceed 500

Public standpipes can operate at a low pressure Distribution systems that serve only standpipes

may therefore use low pressure piping whereas the pipes for distribution systems with house

connections generally have to be of a higher pressure class Water collected at a public standpipe

will have to be carried home in a container This means that the water that was safe at the

moment of drawing may no longer be so at the moment it is used in the house Water

consumption from standpipes generally is not higher than 20-30 litres per person per day

This consumption increases when other facilities are added to reduce the amount of water

women and children have to carry home Water use for other purposes other than drinking and

cooking is likely to be curtailed when the water has to be fetched from a standpipe

Page | 20

Yard and house connections will usually encourage a more generous water use for personal

hygiene and cleaning purposes Wastage of water from standpipes can be a serious problem

especially when users fail to turn off the taps Furthermore poor drainage of spilled water may

cause stagnant pools of dirty water with the associated health hazards It is also not uncommon

for the taps to be damaged by the users and pilferage sometimes occurs These problems occur

particularly when designs do not meet the user requirements

In spite of their shortcomings group connections and public standpipes are really the only

practical options for water distribution at minimum cost to a large number of people who cannot

afford the much higher costs of house or yard connections In fact housing is frequently not

suitably constructed to allow the installation of internal plumbing It would often be impossible

for a small community to obtain the substantial capital for a water distribution system with house

connections Also the costs of adequate disposal of the considerable amounts of wastewater

generated by a house connected water supply service would place an additional heavy financial

burden on the community Consequently public standpipes have to be provided and the principal

concern should be to lessen their inherent shortcomings as much as possible (Hofkes E H et al

1981)

261 Water Demand Variation

The daily water demand in a community area will vary during the year due to seasonal climate

patterns the work situation and other factors such as cultural or religious occasions The

maximum daily demand is usually estimated by adding 10-30 to the average daily demand

Thus the peak factor for the daily water demand (k1) is 11-13

The hourly variation in domestic water demand during the day is much greater Generally two

peak periods can be observed one in the morning and one late in the afternoon as shown in fig

28 below The peak hour demand can be expressed as the average hourly demand multiplied by

the hourly peak factor (k2) For a particular distribution area this factor depends on the size and

character of the community served The hourly peak factor tends to be high for small villages It

is usually lower for larger communities and small towns Where roof tanks or other water storage

vessels are common the hourly peak factor will be further reduced

Page | 21

Usually the factor k2 is chosen in the 15-25 range Where a pipe connection is designed to

supply a small group of consumers a higher value should be adopted because of the effects of

instantaneous demand A water distribution system is typically designed to cater for the

maximum hourly demand This peak demand may then be computed as k1 x k2 x average hourly

demand (Hofkes E H et al 1981)

Figure 28 Variation of domestic water demand during the day

262 Balancing storageWithout storage of water in the distribution area the source of supply and the water treatment

plant would have to be able to follow all fluctuations in the water demand of the community

served This is generally not economical and sometimes not even technically feasible The

design capacities of the various components of a water supply system are usually chosen as

indicated

In summary

System component Design capacity

Water source Peak day water demand

Raw water main Peak day water demand

Treatment plant Peak day water demand

Page | 22

Transmission main Peak day water demand

The service reservoir is provided to balance the (constant) supply rate from the water

sourcetreatment plant with the fluctuating water demand in the distribution area The storage

volume should be large enough to accommodate the cumulative differences between water

supply and demand (Hofkes E H et al 1981)

Figure 29 Design capacities for water supply system components

263 Distribution system design

A typical range of velocities in distribution pipes is between 05 and 10 ms occasionally up to 2

ms The hydraulic gradients usually range between 1 and 5 mkm occasionally up to 10 mkm

In case of smaller pipes D lt 50 mm the hydraulic gradient can even be higher

The pressure criterion is dependent on topographic conditions availability of water at the source

and overall condition of the pipes The minimum pressures should not drop below 5-10 meter

water column In larger distribution areas where water scarcity is not an issue the minimum

pressures can range between 20 and 30 mwc above street level where there are house

connections This is sufficient for supply of 2-3 storey buildings Pressures higher than 60 mwc

Page | 23

should be avoided in general due to increased leakage and risks of bursts especially in poorly

maintained networks

After choosing a preliminary supply scheme (gravitypumping) and type of network layout

(branchedlooped) with its main components the distribution area is divided into a number of

demand districts according to the topography land use classification and density of population

Boundaries may be drawn along rivers roads high points or other features that distinguish each

district The secondary mains and distribution pipes can then be plotted on the plan

Once all the sectors are fixed the population for each district can be estimated or computed from

data collected in the community involvement process The water demand per district is then

computed using per capita water usage figures for domestic water consumption and selected

values for the other non-domestic water requirements including productive uses This per capita

usage figure may vary depending on the water service level that the community in the concerned

district has decided on (Hofkes E H et al 1981)

264 Pipes

The water from public water supply system to individual buildings is supplied through pipes A

large proportion of capital is invested on pipes while designing water supply distribution system

The following factors should be considered in selection of pipes

Strength of pipe

Water carrying capacity

Life and durability of pipe

Expenditure on transportation

Jointing process maintenance and repairs

Several different types of pipe are used in distribution systems They all have advantages and

disadvantages related to cost installation strength and corrosion The most common types of

pipe are known by their abbreviations They include Cast Iron Pipe (CIP) Ductile Iron Pipe

(DIP) Steel Pipe (ST) Asbestos-Cement Pipe (AC) Polyvinyl Chloride Pipe (PVC) and

Unplasticised Polyvinyl Chloride Pipe (UPVC)

Page | 24

UPVC (unplasticized polyvinylchloride) pipes and fittings exhibit excellent resistance to

aggressive environments both naturally occurring and as a result of industrial activity They are

resistant to almost all types of corrosion either chemical or electrochemical in nature

Since uPVC is a non-conductor galvanic and electro chemical effects do not occur in UPVC

pipes

UPVC Pipes and fittings are often used in the following circumstances

bull For drinking water pipe distribution systems both main and supply lines

bull Sewer and discharge pipe systems

Steel pipe is lighter than iron pipe and is easier to handle and install It is more flexible than iron

pipe and doesnt require as much care when bedded in the trench The main disadvantage of steel

pipe is that it is very susceptible to corrosion and should be coated both inside and outside It

doesnt have the same bearing strength that cast or ductile iron does and may collapse under

vacuum conditions Steel pipe may be joined the same way that cast is joined It may also be

joined using threaded connections (Sacramento Water Distribution System Manual 2000)

Cast iron and ductile iron pipe are known for their strength and load bearing capacity Most of

the iron pipe that has been installed in the past 40 years is ductile iron pipe Ductile iron is

stronger and less rigid than gray cast iron pipe The main disadvantages of iron pipe are that it is

heavy and subject to corrosion from the inside and the outside It should be coated with a

corrosion resistant external coating and in certain soil conditions may require some type of

cathodic protection to achieve its normal service life

Cast and ductile iron pipes can be joined by several different means Flanged joints are used

above ground The most common means of joining them underground are the bell and spigot (O-

ring push-on) and the mechanical joint (MJ) connections Care must be taken when installing and

bedding CIP and DIP are both brittle and dont flex The bell holes should only be as wide as the

bell portion of the pipe Otherwise stresses from improper bedding can cause it to crack

(Sacramento Water Distribution System Manual 2000)

Page | 25

Page | 26

2641 Pipes Appurtenances

Valves

Valves are used to control flow in a water system Most of the valves in a distribution system are

installed for isolation of sections of piping for maintenance and repair Control valves like

pressure reducing valves altitude valves pressure relief valves pressure sustaining valves and

pump control valves are designed to control pressures and throttle flows to prevent damage to the

system Air relief valves can vent trapped air from the system Check valves allow water to flow

only in one direction

Valves may be operated by hand or by actuator Actuators generally are electric and may be

operated locally or by remote control Where there is no local power supply portable power

packs may be used

Some examples of valves include

Gate Valve - Gate valves are the most common valves in a distribution system They are used for

isolation of equipment and piping They should never be used to throttle flow This will cause

damage to the valve face Open gate valves have the less friction loss than any other type of

valve Gate valves can have plug type disks or split gates Split gates are used in higher pressure

applications

Butterfly valves - Butterfly valves serve the same purpose as gate valves These valves usually

open and close with a quarter of a turn of the valve disc Larger valves will have a gear box on

the stem and will require a number of turns to open Butterfly valves are easier to open than gate

valves usually without the need for a bypass but have more friction loss when open They can

also be used for throttling flow without damaging the disc Caution should be used when filling a

line through a butterfly valve

Air Release Valve - Air release valves are used to allow air that may be trapped in the line to

escape The trapped air can create pressure and pumping problems milky-water complaints and

pressure spikes that resemble water hammer They are very useful in systems that are in hilly

country They should be located at the top of hills where the trapped air will collect

Page | 27

They are also used on booster pumps and wells to removed trapped air Combination air release

valves will also let air in when a vacuum occurs This is done to protect the piping They can also

be used to vent a line that is being drained All air-release valves should be equipped with

isolating valves for easy removal and repair of the air valves (Sacramento Water Distribution

System Manual 2000)

Section Valves - The valves should be placed in such a way that rationing of water can be done

by closing suitable parts of the supply for certain periods Whenever possible the section valves

should be placed in a joint valve chamber with air valves or washouts and upstream of these

valves In urban areas where fire-fighting is provided for there should be an isolating valve

downstream each fire hydrant (Water Design Manual 2005 Kenya)

Valve chambers

Large valves on trunk pipelines should be located in accessible chambers to facilitate

maintenance Smaller gate valves are usually buried Valve chambers should be at least 1000 x

1000mm internally There must not be UPVC-pipes within the chamber The cover should be

lockable The chamber should be drained through the floor or through a drain pipe

Hydrants

The fire insurance rates for residents on the system will be dependent in part on the proper

spacing and discharge capabilities of the fire hydrants in the system Hydrants should not be

more than 500-600 feet apart in residential districts The spacing requirements in industrial and

rural districts may vary They should be located at the end of every dead end line Hydrants

should be operated every 6 months and flow tested annually

Fire hydrants should never be placed on less than a 6 inch line if it is to be used for fire

protection In addition to provide fire protection hydrants can also be useful for flushing lines

venting lines as they are filled and pressure and flow testing Hydrants on smaller lines (4 inch

and down) will not supply enough water to fight a fire but may be used to flush dead end lines

Page | 28

Thrust Blocks

Wherever a bend elbow tee or dead-end exists in a pipeline having flexible joints a force is

exerted which tends to open the joints nearest the fittings The magnitude of this force varies

with the amount of bend the diameter of pipe and the pressure inside the pipe When

determining the resultant thrust for a given pipe it is advisable to use the maximum working

pressure anticipated in the pipe plus an allowance for surges or water hammer

Once the resultant thrust has been determined for a particular bend it becomes necessary to

provide a backing block of such size to resist the thrust The thrust must ultimately be borne by

the side of the pipe trench and the surrounding soil The purpose of the backing block is to

spread the thrust over an area sufficiently large that the undisturbed earth can support it

2642 Washouts

A washout is seldom used for scouring or washing out a main because its diameter is too small to

create sufficient flow velocity in the main to wash out debris Its principal use is for emptying a

main or for the removal of stagnant or dirty water

Primary washouts may be installed to drain to a watercourse the majority of the length between

section valves Secondary washouts of smaller diameter can then be used to empty undrained

subsections as required Sizes particularly primary washouts need to be calculated according to

the draindown time (Twort 5th Edition)

2643 Break Pressure tanks

Static head is the difference in elevation from the source to any point on the ground profile

Static head must always be considered because excessive pressure in the pipe from the elevation

head can rapture the pipe or pipe connections Piping is rated by its ability to withstand an

internal pressure without breaking The ability is a function of the type of pipe material and

thickness of the wall pipe

Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure

that will rupture the pipe or cause failures at the joints

Page | 29

The function of a break pressure tank is to allow the flow to discharge into the atmosphere

thereby reducing its hydrostatic pressure to zero and establishing a new static level A general

rule of thumb is that the static head at any given point within the conduction line should not

exceed 100m of head There is no minimum required capacity for a break pressure tank as long

as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)

Page | 30

Chapter Three

30 METHODOLOGY

31 Introduction

Different data was needed for the design of a water supply system in Ongata Rongai Methods of

data collection were established beforehand to ensure the process was efficient Once the data

was collected it was analyzed to produce an outcome that satisfied the objective of the report

The data collected included

a) Population of the area

b) Land use

c) Topographical data

d) Existing water supply

e) Information on water consumption per capita in the area

In order to obtain this data various data collection methods were used as shown below

32 Data collection methods

Various methods were employed to collect data needed for the design of the system Both

primary and secondary data was needed The quantitative methods employed were to enable me

to obtain firsthand information needed for the project These include

a) Questionnaires

b) Interviews

c) Literature review

d) Government agencies

e) Direct observation

321 QuestionnairesQuestionnaires were prepared to aid with the collection of data The questionnaires were given to

the relevant parties In order to obtain an overview of water use in the area the questionnaire was

handed to the community for a brief description on how they use the water

Page | 31

With regards to the existing water supply it was necessary to involve Oloolaiser Water with the

use of questionnaires to obtain information on their existing system

322 InterviewsIn addition to questionnaires face to face interviews were also conducted The interviews were

done to collect data on the challenges facing the existing supply of water and the sources

available for people in the area These interviews were carried out with the members living in the

project area

Information on the proposed source was also required This particular interview was conducted

with the engineer who designed the dam itself The current population of the town and the

change of boundaries in the area over the past twenty years information was obtained from an

interview conducted with the technical manager at Oloolaiser Water and Sewerage Company

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area

323 Literature reviewDifferent reports were reviewed to get information in various areas This included the past

census reports to obtain the population of people in the area Information on land use and project

location description was also obtained from the NEMA Environmental Action plan for Kajiado

Land use data was necessary to establish where the pipeline would pass

324 Government AgenciesIn order to collect topographical data a map from the Survey of Kenya was obtained for the area

This map had information on the roads contours rivers all the natural and man-made features

which were necessary for the design of the system Information on sources of water supply in the

area was also obtained from the Oloolaiser water and sewerage company who are the water

service providers in the area

325 Direct ObservationDirect observation for information on settlement and land use was necessary because of the rate

at which the town is growing This was especially needed for the land adjacent to the road

because that was where the pipeline would pass and also to consider alternative routes for the

pipeline

Page | 32

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Figure 22 Branched and looped distribution system

Branched systems are easy to design The direction of the water flow and the flow rates can

readily be determined for all pipes This is different in looped distribution networks where

consumers can be supplied from more than one direction Looped networks greatly improve the

hydraulics of the distribution system This is of major importance in the event that one of the

mains is out of operation for cleaning or repair

A looped network usually has a skeleton of secondary mains that can also be in a form of branch

one loop or a number of loops From there the water is conveyed towards the distribution pipes

and further to the consumers The secondary mains are connected to one or more loops or rings

The network in large (urban) distribution systems will be much more complex essentially a

combination of loops and branches with lots of interconnected pipes that requires many valves

and special parts as shown below in figure 23 To save on equipment costs over-crossing pipes

that are not interconnected may be used but at the cost of reduced reliability as shown below in

figure 24

Page | 16

Figure 23 Fully interconnected pipes

Figure 24 Overcrossing single pipes

Points at which the water is delivered to the users are called service connections The number

and type of service connections has considerable influence on the choice of a network layout

Page | 17

The following types of service connections may be distinguished

House connection

Yard connection

Group connection

Public standpipe

A house connection is a water service pipe connected with in-house plumbing to one or more

taps eg in the kitchen and bathroom Usually 38 inch (9 mm) and 12 inch (12 mm) taps are

used A typical layout is shown in figure 25

Figure 25 House connection

The service pipe is connected to the distribution main in the street by means of a T-piece on

small-diameter pipes a special insert piece or a saddle on larger-size secondary pipes A special

insert piece is mostly used for cast iron and ductile iron pipes

A yard connection is quite similar to a house connection the only difference being that the tap is

placed in the yard outside the house No in-house piping and fixtures are provided as shown

below in figure 26

Page | 18

Figure 26 Yard connection

Plastic (polyvinyl chloride or polyethylene) cast iron and galvanized steel pipes are used for

both house connections and yard connections

Group connections are outside taps that are shared by a clearly defined group of households

often neighbours Each family may pay the same (flat) share or contributions may be weighed

according to the estimated volume of water each family consumes Consumption estimates may

be based on indicators such as family size and composition and types of use by the different

households Sometimes the taps can be locked and a local committee holds the key and manages

the use and financing

Public standpipes can have one or more taps Single-tap and double-tap standpipes are the most

common types in rural areas They are made of brickwork masonry or concrete or use wooden

poles and similar materials The design should be done in close consultation with the users

(especially women) in order to arrive at an ergonomically optimal solution Standpipes may have

platforms at different levels making it easy for adults and children to use them with containers

of different sizes Examples are shown in figures 27 Cattle watering andor washing andor

bathing facilities may be constructed nearby The design and often also the construction are best

done in consultation and with participation of the user households ie both men and women

Public taps drawing from a small reservoir (cistern) represent an alternative method of water

distribution

Page | 19

Figure 27 Public Standpipes

Each standpipe should be situated at a suitable point within the community area in order to limit

the distance the water users have to go to collect their water The walking distance for the most

distant user of a standpipe should whenever possible be limited to 200 m in sparsely populated

rural areas 500 m may be acceptable The required discharge capacity of a standpipe normally is

about 14-18 litresminute at each outlet A single-tap standpipe should preferably be used by not

more than 40-70 people a multiple-tap standpipe may provide a reasonable service for up to

250-300 persons in no case should the number of users dependent on one standpipe exceed 500

Public standpipes can operate at a low pressure Distribution systems that serve only standpipes

may therefore use low pressure piping whereas the pipes for distribution systems with house

connections generally have to be of a higher pressure class Water collected at a public standpipe

will have to be carried home in a container This means that the water that was safe at the

moment of drawing may no longer be so at the moment it is used in the house Water

consumption from standpipes generally is not higher than 20-30 litres per person per day

This consumption increases when other facilities are added to reduce the amount of water

women and children have to carry home Water use for other purposes other than drinking and

cooking is likely to be curtailed when the water has to be fetched from a standpipe

Page | 20

Yard and house connections will usually encourage a more generous water use for personal

hygiene and cleaning purposes Wastage of water from standpipes can be a serious problem

especially when users fail to turn off the taps Furthermore poor drainage of spilled water may

cause stagnant pools of dirty water with the associated health hazards It is also not uncommon

for the taps to be damaged by the users and pilferage sometimes occurs These problems occur

particularly when designs do not meet the user requirements

In spite of their shortcomings group connections and public standpipes are really the only

practical options for water distribution at minimum cost to a large number of people who cannot

afford the much higher costs of house or yard connections In fact housing is frequently not

suitably constructed to allow the installation of internal plumbing It would often be impossible

for a small community to obtain the substantial capital for a water distribution system with house

connections Also the costs of adequate disposal of the considerable amounts of wastewater

generated by a house connected water supply service would place an additional heavy financial

burden on the community Consequently public standpipes have to be provided and the principal

concern should be to lessen their inherent shortcomings as much as possible (Hofkes E H et al

1981)

261 Water Demand Variation

The daily water demand in a community area will vary during the year due to seasonal climate

patterns the work situation and other factors such as cultural or religious occasions The

maximum daily demand is usually estimated by adding 10-30 to the average daily demand

Thus the peak factor for the daily water demand (k1) is 11-13

The hourly variation in domestic water demand during the day is much greater Generally two

peak periods can be observed one in the morning and one late in the afternoon as shown in fig

28 below The peak hour demand can be expressed as the average hourly demand multiplied by

the hourly peak factor (k2) For a particular distribution area this factor depends on the size and

character of the community served The hourly peak factor tends to be high for small villages It

is usually lower for larger communities and small towns Where roof tanks or other water storage

vessels are common the hourly peak factor will be further reduced

Page | 21

Usually the factor k2 is chosen in the 15-25 range Where a pipe connection is designed to

supply a small group of consumers a higher value should be adopted because of the effects of

instantaneous demand A water distribution system is typically designed to cater for the

maximum hourly demand This peak demand may then be computed as k1 x k2 x average hourly

demand (Hofkes E H et al 1981)

Figure 28 Variation of domestic water demand during the day

262 Balancing storageWithout storage of water in the distribution area the source of supply and the water treatment

plant would have to be able to follow all fluctuations in the water demand of the community

served This is generally not economical and sometimes not even technically feasible The

design capacities of the various components of a water supply system are usually chosen as

indicated

In summary

System component Design capacity

Water source Peak day water demand

Raw water main Peak day water demand

Treatment plant Peak day water demand

Page | 22

Transmission main Peak day water demand

The service reservoir is provided to balance the (constant) supply rate from the water

sourcetreatment plant with the fluctuating water demand in the distribution area The storage

volume should be large enough to accommodate the cumulative differences between water

supply and demand (Hofkes E H et al 1981)

Figure 29 Design capacities for water supply system components

263 Distribution system design

A typical range of velocities in distribution pipes is between 05 and 10 ms occasionally up to 2

ms The hydraulic gradients usually range between 1 and 5 mkm occasionally up to 10 mkm

In case of smaller pipes D lt 50 mm the hydraulic gradient can even be higher

The pressure criterion is dependent on topographic conditions availability of water at the source

and overall condition of the pipes The minimum pressures should not drop below 5-10 meter

water column In larger distribution areas where water scarcity is not an issue the minimum

pressures can range between 20 and 30 mwc above street level where there are house

connections This is sufficient for supply of 2-3 storey buildings Pressures higher than 60 mwc

Page | 23

should be avoided in general due to increased leakage and risks of bursts especially in poorly

maintained networks

After choosing a preliminary supply scheme (gravitypumping) and type of network layout

(branchedlooped) with its main components the distribution area is divided into a number of

demand districts according to the topography land use classification and density of population

Boundaries may be drawn along rivers roads high points or other features that distinguish each

district The secondary mains and distribution pipes can then be plotted on the plan

Once all the sectors are fixed the population for each district can be estimated or computed from

data collected in the community involvement process The water demand per district is then

computed using per capita water usage figures for domestic water consumption and selected

values for the other non-domestic water requirements including productive uses This per capita

usage figure may vary depending on the water service level that the community in the concerned

district has decided on (Hofkes E H et al 1981)

264 Pipes

The water from public water supply system to individual buildings is supplied through pipes A

large proportion of capital is invested on pipes while designing water supply distribution system

The following factors should be considered in selection of pipes

Strength of pipe

Water carrying capacity

Life and durability of pipe

Expenditure on transportation

Jointing process maintenance and repairs

Several different types of pipe are used in distribution systems They all have advantages and

disadvantages related to cost installation strength and corrosion The most common types of

pipe are known by their abbreviations They include Cast Iron Pipe (CIP) Ductile Iron Pipe

(DIP) Steel Pipe (ST) Asbestos-Cement Pipe (AC) Polyvinyl Chloride Pipe (PVC) and

Unplasticised Polyvinyl Chloride Pipe (UPVC)

Page | 24

UPVC (unplasticized polyvinylchloride) pipes and fittings exhibit excellent resistance to

aggressive environments both naturally occurring and as a result of industrial activity They are

resistant to almost all types of corrosion either chemical or electrochemical in nature

Since uPVC is a non-conductor galvanic and electro chemical effects do not occur in UPVC

pipes

UPVC Pipes and fittings are often used in the following circumstances

bull For drinking water pipe distribution systems both main and supply lines

bull Sewer and discharge pipe systems

Steel pipe is lighter than iron pipe and is easier to handle and install It is more flexible than iron

pipe and doesnt require as much care when bedded in the trench The main disadvantage of steel

pipe is that it is very susceptible to corrosion and should be coated both inside and outside It

doesnt have the same bearing strength that cast or ductile iron does and may collapse under

vacuum conditions Steel pipe may be joined the same way that cast is joined It may also be

joined using threaded connections (Sacramento Water Distribution System Manual 2000)

Cast iron and ductile iron pipe are known for their strength and load bearing capacity Most of

the iron pipe that has been installed in the past 40 years is ductile iron pipe Ductile iron is

stronger and less rigid than gray cast iron pipe The main disadvantages of iron pipe are that it is

heavy and subject to corrosion from the inside and the outside It should be coated with a

corrosion resistant external coating and in certain soil conditions may require some type of

cathodic protection to achieve its normal service life

Cast and ductile iron pipes can be joined by several different means Flanged joints are used

above ground The most common means of joining them underground are the bell and spigot (O-

ring push-on) and the mechanical joint (MJ) connections Care must be taken when installing and

bedding CIP and DIP are both brittle and dont flex The bell holes should only be as wide as the

bell portion of the pipe Otherwise stresses from improper bedding can cause it to crack

(Sacramento Water Distribution System Manual 2000)

Page | 25

Page | 26

2641 Pipes Appurtenances

Valves

Valves are used to control flow in a water system Most of the valves in a distribution system are

installed for isolation of sections of piping for maintenance and repair Control valves like

pressure reducing valves altitude valves pressure relief valves pressure sustaining valves and

pump control valves are designed to control pressures and throttle flows to prevent damage to the

system Air relief valves can vent trapped air from the system Check valves allow water to flow

only in one direction

Valves may be operated by hand or by actuator Actuators generally are electric and may be

operated locally or by remote control Where there is no local power supply portable power

packs may be used

Some examples of valves include

Gate Valve - Gate valves are the most common valves in a distribution system They are used for

isolation of equipment and piping They should never be used to throttle flow This will cause

damage to the valve face Open gate valves have the less friction loss than any other type of

valve Gate valves can have plug type disks or split gates Split gates are used in higher pressure

applications

Butterfly valves - Butterfly valves serve the same purpose as gate valves These valves usually

open and close with a quarter of a turn of the valve disc Larger valves will have a gear box on

the stem and will require a number of turns to open Butterfly valves are easier to open than gate

valves usually without the need for a bypass but have more friction loss when open They can

also be used for throttling flow without damaging the disc Caution should be used when filling a

line through a butterfly valve

Air Release Valve - Air release valves are used to allow air that may be trapped in the line to

escape The trapped air can create pressure and pumping problems milky-water complaints and

pressure spikes that resemble water hammer They are very useful in systems that are in hilly

country They should be located at the top of hills where the trapped air will collect

Page | 27

They are also used on booster pumps and wells to removed trapped air Combination air release

valves will also let air in when a vacuum occurs This is done to protect the piping They can also

be used to vent a line that is being drained All air-release valves should be equipped with

isolating valves for easy removal and repair of the air valves (Sacramento Water Distribution

System Manual 2000)

Section Valves - The valves should be placed in such a way that rationing of water can be done

by closing suitable parts of the supply for certain periods Whenever possible the section valves

should be placed in a joint valve chamber with air valves or washouts and upstream of these

valves In urban areas where fire-fighting is provided for there should be an isolating valve

downstream each fire hydrant (Water Design Manual 2005 Kenya)

Valve chambers

Large valves on trunk pipelines should be located in accessible chambers to facilitate

maintenance Smaller gate valves are usually buried Valve chambers should be at least 1000 x

1000mm internally There must not be UPVC-pipes within the chamber The cover should be

lockable The chamber should be drained through the floor or through a drain pipe

Hydrants

The fire insurance rates for residents on the system will be dependent in part on the proper

spacing and discharge capabilities of the fire hydrants in the system Hydrants should not be

more than 500-600 feet apart in residential districts The spacing requirements in industrial and

rural districts may vary They should be located at the end of every dead end line Hydrants

should be operated every 6 months and flow tested annually

Fire hydrants should never be placed on less than a 6 inch line if it is to be used for fire

protection In addition to provide fire protection hydrants can also be useful for flushing lines

venting lines as they are filled and pressure and flow testing Hydrants on smaller lines (4 inch

and down) will not supply enough water to fight a fire but may be used to flush dead end lines

Page | 28

Thrust Blocks

Wherever a bend elbow tee or dead-end exists in a pipeline having flexible joints a force is

exerted which tends to open the joints nearest the fittings The magnitude of this force varies

with the amount of bend the diameter of pipe and the pressure inside the pipe When

determining the resultant thrust for a given pipe it is advisable to use the maximum working

pressure anticipated in the pipe plus an allowance for surges or water hammer

Once the resultant thrust has been determined for a particular bend it becomes necessary to

provide a backing block of such size to resist the thrust The thrust must ultimately be borne by

the side of the pipe trench and the surrounding soil The purpose of the backing block is to

spread the thrust over an area sufficiently large that the undisturbed earth can support it

2642 Washouts

A washout is seldom used for scouring or washing out a main because its diameter is too small to

create sufficient flow velocity in the main to wash out debris Its principal use is for emptying a

main or for the removal of stagnant or dirty water

Primary washouts may be installed to drain to a watercourse the majority of the length between

section valves Secondary washouts of smaller diameter can then be used to empty undrained

subsections as required Sizes particularly primary washouts need to be calculated according to

the draindown time (Twort 5th Edition)

2643 Break Pressure tanks

Static head is the difference in elevation from the source to any point on the ground profile

Static head must always be considered because excessive pressure in the pipe from the elevation

head can rapture the pipe or pipe connections Piping is rated by its ability to withstand an

internal pressure without breaking The ability is a function of the type of pipe material and

thickness of the wall pipe

Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure

that will rupture the pipe or cause failures at the joints

Page | 29

The function of a break pressure tank is to allow the flow to discharge into the atmosphere

thereby reducing its hydrostatic pressure to zero and establishing a new static level A general

rule of thumb is that the static head at any given point within the conduction line should not

exceed 100m of head There is no minimum required capacity for a break pressure tank as long

as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)

Page | 30

Chapter Three

30 METHODOLOGY

31 Introduction

Different data was needed for the design of a water supply system in Ongata Rongai Methods of

data collection were established beforehand to ensure the process was efficient Once the data

was collected it was analyzed to produce an outcome that satisfied the objective of the report

The data collected included

a) Population of the area

b) Land use

c) Topographical data

d) Existing water supply

e) Information on water consumption per capita in the area

In order to obtain this data various data collection methods were used as shown below

32 Data collection methods

Various methods were employed to collect data needed for the design of the system Both

primary and secondary data was needed The quantitative methods employed were to enable me

to obtain firsthand information needed for the project These include

a) Questionnaires

b) Interviews

c) Literature review

d) Government agencies

e) Direct observation

321 QuestionnairesQuestionnaires were prepared to aid with the collection of data The questionnaires were given to

the relevant parties In order to obtain an overview of water use in the area the questionnaire was

handed to the community for a brief description on how they use the water

Page | 31

With regards to the existing water supply it was necessary to involve Oloolaiser Water with the

use of questionnaires to obtain information on their existing system

322 InterviewsIn addition to questionnaires face to face interviews were also conducted The interviews were

done to collect data on the challenges facing the existing supply of water and the sources

available for people in the area These interviews were carried out with the members living in the

project area

Information on the proposed source was also required This particular interview was conducted

with the engineer who designed the dam itself The current population of the town and the

change of boundaries in the area over the past twenty years information was obtained from an

interview conducted with the technical manager at Oloolaiser Water and Sewerage Company

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area

323 Literature reviewDifferent reports were reviewed to get information in various areas This included the past

census reports to obtain the population of people in the area Information on land use and project

location description was also obtained from the NEMA Environmental Action plan for Kajiado

Land use data was necessary to establish where the pipeline would pass

324 Government AgenciesIn order to collect topographical data a map from the Survey of Kenya was obtained for the area

This map had information on the roads contours rivers all the natural and man-made features

which were necessary for the design of the system Information on sources of water supply in the

area was also obtained from the Oloolaiser water and sewerage company who are the water

service providers in the area

325 Direct ObservationDirect observation for information on settlement and land use was necessary because of the rate

at which the town is growing This was especially needed for the land adjacent to the road

because that was where the pipeline would pass and also to consider alternative routes for the

pipeline

Page | 32

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Figure 23 Fully interconnected pipes

Figure 24 Overcrossing single pipes

Points at which the water is delivered to the users are called service connections The number

and type of service connections has considerable influence on the choice of a network layout

Page | 17

The following types of service connections may be distinguished

House connection

Yard connection

Group connection

Public standpipe

A house connection is a water service pipe connected with in-house plumbing to one or more

taps eg in the kitchen and bathroom Usually 38 inch (9 mm) and 12 inch (12 mm) taps are

used A typical layout is shown in figure 25

Figure 25 House connection

The service pipe is connected to the distribution main in the street by means of a T-piece on

small-diameter pipes a special insert piece or a saddle on larger-size secondary pipes A special

insert piece is mostly used for cast iron and ductile iron pipes

A yard connection is quite similar to a house connection the only difference being that the tap is

placed in the yard outside the house No in-house piping and fixtures are provided as shown

below in figure 26

Page | 18

Figure 26 Yard connection

Plastic (polyvinyl chloride or polyethylene) cast iron and galvanized steel pipes are used for

both house connections and yard connections

Group connections are outside taps that are shared by a clearly defined group of households

often neighbours Each family may pay the same (flat) share or contributions may be weighed

according to the estimated volume of water each family consumes Consumption estimates may

be based on indicators such as family size and composition and types of use by the different

households Sometimes the taps can be locked and a local committee holds the key and manages

the use and financing

Public standpipes can have one or more taps Single-tap and double-tap standpipes are the most

common types in rural areas They are made of brickwork masonry or concrete or use wooden

poles and similar materials The design should be done in close consultation with the users

(especially women) in order to arrive at an ergonomically optimal solution Standpipes may have

platforms at different levels making it easy for adults and children to use them with containers

of different sizes Examples are shown in figures 27 Cattle watering andor washing andor

bathing facilities may be constructed nearby The design and often also the construction are best

done in consultation and with participation of the user households ie both men and women

Public taps drawing from a small reservoir (cistern) represent an alternative method of water

distribution

Page | 19

Figure 27 Public Standpipes

Each standpipe should be situated at a suitable point within the community area in order to limit

the distance the water users have to go to collect their water The walking distance for the most

distant user of a standpipe should whenever possible be limited to 200 m in sparsely populated

rural areas 500 m may be acceptable The required discharge capacity of a standpipe normally is

about 14-18 litresminute at each outlet A single-tap standpipe should preferably be used by not

more than 40-70 people a multiple-tap standpipe may provide a reasonable service for up to

250-300 persons in no case should the number of users dependent on one standpipe exceed 500

Public standpipes can operate at a low pressure Distribution systems that serve only standpipes

may therefore use low pressure piping whereas the pipes for distribution systems with house

connections generally have to be of a higher pressure class Water collected at a public standpipe

will have to be carried home in a container This means that the water that was safe at the

moment of drawing may no longer be so at the moment it is used in the house Water

consumption from standpipes generally is not higher than 20-30 litres per person per day

This consumption increases when other facilities are added to reduce the amount of water

women and children have to carry home Water use for other purposes other than drinking and

cooking is likely to be curtailed when the water has to be fetched from a standpipe

Page | 20

Yard and house connections will usually encourage a more generous water use for personal

hygiene and cleaning purposes Wastage of water from standpipes can be a serious problem

especially when users fail to turn off the taps Furthermore poor drainage of spilled water may

cause stagnant pools of dirty water with the associated health hazards It is also not uncommon

for the taps to be damaged by the users and pilferage sometimes occurs These problems occur

particularly when designs do not meet the user requirements

In spite of their shortcomings group connections and public standpipes are really the only

practical options for water distribution at minimum cost to a large number of people who cannot

afford the much higher costs of house or yard connections In fact housing is frequently not

suitably constructed to allow the installation of internal plumbing It would often be impossible

for a small community to obtain the substantial capital for a water distribution system with house

connections Also the costs of adequate disposal of the considerable amounts of wastewater

generated by a house connected water supply service would place an additional heavy financial

burden on the community Consequently public standpipes have to be provided and the principal

concern should be to lessen their inherent shortcomings as much as possible (Hofkes E H et al

1981)

261 Water Demand Variation

The daily water demand in a community area will vary during the year due to seasonal climate

patterns the work situation and other factors such as cultural or religious occasions The

maximum daily demand is usually estimated by adding 10-30 to the average daily demand

Thus the peak factor for the daily water demand (k1) is 11-13

The hourly variation in domestic water demand during the day is much greater Generally two

peak periods can be observed one in the morning and one late in the afternoon as shown in fig

28 below The peak hour demand can be expressed as the average hourly demand multiplied by

the hourly peak factor (k2) For a particular distribution area this factor depends on the size and

character of the community served The hourly peak factor tends to be high for small villages It

is usually lower for larger communities and small towns Where roof tanks or other water storage

vessels are common the hourly peak factor will be further reduced

Page | 21

Usually the factor k2 is chosen in the 15-25 range Where a pipe connection is designed to

supply a small group of consumers a higher value should be adopted because of the effects of

instantaneous demand A water distribution system is typically designed to cater for the

maximum hourly demand This peak demand may then be computed as k1 x k2 x average hourly

demand (Hofkes E H et al 1981)

Figure 28 Variation of domestic water demand during the day

262 Balancing storageWithout storage of water in the distribution area the source of supply and the water treatment

plant would have to be able to follow all fluctuations in the water demand of the community

served This is generally not economical and sometimes not even technically feasible The

design capacities of the various components of a water supply system are usually chosen as

indicated

In summary

System component Design capacity

Water source Peak day water demand

Raw water main Peak day water demand

Treatment plant Peak day water demand

Page | 22

Transmission main Peak day water demand

The service reservoir is provided to balance the (constant) supply rate from the water

sourcetreatment plant with the fluctuating water demand in the distribution area The storage

volume should be large enough to accommodate the cumulative differences between water

supply and demand (Hofkes E H et al 1981)

Figure 29 Design capacities for water supply system components

263 Distribution system design

A typical range of velocities in distribution pipes is between 05 and 10 ms occasionally up to 2

ms The hydraulic gradients usually range between 1 and 5 mkm occasionally up to 10 mkm

In case of smaller pipes D lt 50 mm the hydraulic gradient can even be higher

The pressure criterion is dependent on topographic conditions availability of water at the source

and overall condition of the pipes The minimum pressures should not drop below 5-10 meter

water column In larger distribution areas where water scarcity is not an issue the minimum

pressures can range between 20 and 30 mwc above street level where there are house

connections This is sufficient for supply of 2-3 storey buildings Pressures higher than 60 mwc

Page | 23

should be avoided in general due to increased leakage and risks of bursts especially in poorly

maintained networks

After choosing a preliminary supply scheme (gravitypumping) and type of network layout

(branchedlooped) with its main components the distribution area is divided into a number of

demand districts according to the topography land use classification and density of population

Boundaries may be drawn along rivers roads high points or other features that distinguish each

district The secondary mains and distribution pipes can then be plotted on the plan

Once all the sectors are fixed the population for each district can be estimated or computed from

data collected in the community involvement process The water demand per district is then

computed using per capita water usage figures for domestic water consumption and selected

values for the other non-domestic water requirements including productive uses This per capita

usage figure may vary depending on the water service level that the community in the concerned

district has decided on (Hofkes E H et al 1981)

264 Pipes

The water from public water supply system to individual buildings is supplied through pipes A

large proportion of capital is invested on pipes while designing water supply distribution system

The following factors should be considered in selection of pipes

Strength of pipe

Water carrying capacity

Life and durability of pipe

Expenditure on transportation

Jointing process maintenance and repairs

Several different types of pipe are used in distribution systems They all have advantages and

disadvantages related to cost installation strength and corrosion The most common types of

pipe are known by their abbreviations They include Cast Iron Pipe (CIP) Ductile Iron Pipe

(DIP) Steel Pipe (ST) Asbestos-Cement Pipe (AC) Polyvinyl Chloride Pipe (PVC) and

Unplasticised Polyvinyl Chloride Pipe (UPVC)

Page | 24

UPVC (unplasticized polyvinylchloride) pipes and fittings exhibit excellent resistance to

aggressive environments both naturally occurring and as a result of industrial activity They are

resistant to almost all types of corrosion either chemical or electrochemical in nature

Since uPVC is a non-conductor galvanic and electro chemical effects do not occur in UPVC

pipes

UPVC Pipes and fittings are often used in the following circumstances

bull For drinking water pipe distribution systems both main and supply lines

bull Sewer and discharge pipe systems

Steel pipe is lighter than iron pipe and is easier to handle and install It is more flexible than iron

pipe and doesnt require as much care when bedded in the trench The main disadvantage of steel

pipe is that it is very susceptible to corrosion and should be coated both inside and outside It

doesnt have the same bearing strength that cast or ductile iron does and may collapse under

vacuum conditions Steel pipe may be joined the same way that cast is joined It may also be

joined using threaded connections (Sacramento Water Distribution System Manual 2000)

Cast iron and ductile iron pipe are known for their strength and load bearing capacity Most of

the iron pipe that has been installed in the past 40 years is ductile iron pipe Ductile iron is

stronger and less rigid than gray cast iron pipe The main disadvantages of iron pipe are that it is

heavy and subject to corrosion from the inside and the outside It should be coated with a

corrosion resistant external coating and in certain soil conditions may require some type of

cathodic protection to achieve its normal service life

Cast and ductile iron pipes can be joined by several different means Flanged joints are used

above ground The most common means of joining them underground are the bell and spigot (O-

ring push-on) and the mechanical joint (MJ) connections Care must be taken when installing and

bedding CIP and DIP are both brittle and dont flex The bell holes should only be as wide as the

bell portion of the pipe Otherwise stresses from improper bedding can cause it to crack

(Sacramento Water Distribution System Manual 2000)

Page | 25

Page | 26

2641 Pipes Appurtenances

Valves

Valves are used to control flow in a water system Most of the valves in a distribution system are

installed for isolation of sections of piping for maintenance and repair Control valves like

pressure reducing valves altitude valves pressure relief valves pressure sustaining valves and

pump control valves are designed to control pressures and throttle flows to prevent damage to the

system Air relief valves can vent trapped air from the system Check valves allow water to flow

only in one direction

Valves may be operated by hand or by actuator Actuators generally are electric and may be

operated locally or by remote control Where there is no local power supply portable power

packs may be used

Some examples of valves include

Gate Valve - Gate valves are the most common valves in a distribution system They are used for

isolation of equipment and piping They should never be used to throttle flow This will cause

damage to the valve face Open gate valves have the less friction loss than any other type of

valve Gate valves can have plug type disks or split gates Split gates are used in higher pressure

applications

Butterfly valves - Butterfly valves serve the same purpose as gate valves These valves usually

open and close with a quarter of a turn of the valve disc Larger valves will have a gear box on

the stem and will require a number of turns to open Butterfly valves are easier to open than gate

valves usually without the need for a bypass but have more friction loss when open They can

also be used for throttling flow without damaging the disc Caution should be used when filling a

line through a butterfly valve

Air Release Valve - Air release valves are used to allow air that may be trapped in the line to

escape The trapped air can create pressure and pumping problems milky-water complaints and

pressure spikes that resemble water hammer They are very useful in systems that are in hilly

country They should be located at the top of hills where the trapped air will collect

Page | 27

They are also used on booster pumps and wells to removed trapped air Combination air release

valves will also let air in when a vacuum occurs This is done to protect the piping They can also

be used to vent a line that is being drained All air-release valves should be equipped with

isolating valves for easy removal and repair of the air valves (Sacramento Water Distribution

System Manual 2000)

Section Valves - The valves should be placed in such a way that rationing of water can be done

by closing suitable parts of the supply for certain periods Whenever possible the section valves

should be placed in a joint valve chamber with air valves or washouts and upstream of these

valves In urban areas where fire-fighting is provided for there should be an isolating valve

downstream each fire hydrant (Water Design Manual 2005 Kenya)

Valve chambers

Large valves on trunk pipelines should be located in accessible chambers to facilitate

maintenance Smaller gate valves are usually buried Valve chambers should be at least 1000 x

1000mm internally There must not be UPVC-pipes within the chamber The cover should be

lockable The chamber should be drained through the floor or through a drain pipe

Hydrants

The fire insurance rates for residents on the system will be dependent in part on the proper

spacing and discharge capabilities of the fire hydrants in the system Hydrants should not be

more than 500-600 feet apart in residential districts The spacing requirements in industrial and

rural districts may vary They should be located at the end of every dead end line Hydrants

should be operated every 6 months and flow tested annually

Fire hydrants should never be placed on less than a 6 inch line if it is to be used for fire

protection In addition to provide fire protection hydrants can also be useful for flushing lines

venting lines as they are filled and pressure and flow testing Hydrants on smaller lines (4 inch

and down) will not supply enough water to fight a fire but may be used to flush dead end lines

Page | 28

Thrust Blocks

Wherever a bend elbow tee or dead-end exists in a pipeline having flexible joints a force is

exerted which tends to open the joints nearest the fittings The magnitude of this force varies

with the amount of bend the diameter of pipe and the pressure inside the pipe When

determining the resultant thrust for a given pipe it is advisable to use the maximum working

pressure anticipated in the pipe plus an allowance for surges or water hammer

Once the resultant thrust has been determined for a particular bend it becomes necessary to

provide a backing block of such size to resist the thrust The thrust must ultimately be borne by

the side of the pipe trench and the surrounding soil The purpose of the backing block is to

spread the thrust over an area sufficiently large that the undisturbed earth can support it

2642 Washouts

A washout is seldom used for scouring or washing out a main because its diameter is too small to

create sufficient flow velocity in the main to wash out debris Its principal use is for emptying a

main or for the removal of stagnant or dirty water

Primary washouts may be installed to drain to a watercourse the majority of the length between

section valves Secondary washouts of smaller diameter can then be used to empty undrained

subsections as required Sizes particularly primary washouts need to be calculated according to

the draindown time (Twort 5th Edition)

2643 Break Pressure tanks

Static head is the difference in elevation from the source to any point on the ground profile

Static head must always be considered because excessive pressure in the pipe from the elevation

head can rapture the pipe or pipe connections Piping is rated by its ability to withstand an

internal pressure without breaking The ability is a function of the type of pipe material and

thickness of the wall pipe

Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure

that will rupture the pipe or cause failures at the joints

Page | 29

The function of a break pressure tank is to allow the flow to discharge into the atmosphere

thereby reducing its hydrostatic pressure to zero and establishing a new static level A general

rule of thumb is that the static head at any given point within the conduction line should not

exceed 100m of head There is no minimum required capacity for a break pressure tank as long

as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)

Page | 30

Chapter Three

30 METHODOLOGY

31 Introduction

Different data was needed for the design of a water supply system in Ongata Rongai Methods of

data collection were established beforehand to ensure the process was efficient Once the data

was collected it was analyzed to produce an outcome that satisfied the objective of the report

The data collected included

a) Population of the area

b) Land use

c) Topographical data

d) Existing water supply

e) Information on water consumption per capita in the area

In order to obtain this data various data collection methods were used as shown below

32 Data collection methods

Various methods were employed to collect data needed for the design of the system Both

primary and secondary data was needed The quantitative methods employed were to enable me

to obtain firsthand information needed for the project These include

a) Questionnaires

b) Interviews

c) Literature review

d) Government agencies

e) Direct observation

321 QuestionnairesQuestionnaires were prepared to aid with the collection of data The questionnaires were given to

the relevant parties In order to obtain an overview of water use in the area the questionnaire was

handed to the community for a brief description on how they use the water

Page | 31

With regards to the existing water supply it was necessary to involve Oloolaiser Water with the

use of questionnaires to obtain information on their existing system

322 InterviewsIn addition to questionnaires face to face interviews were also conducted The interviews were

done to collect data on the challenges facing the existing supply of water and the sources

available for people in the area These interviews were carried out with the members living in the

project area

Information on the proposed source was also required This particular interview was conducted

with the engineer who designed the dam itself The current population of the town and the

change of boundaries in the area over the past twenty years information was obtained from an

interview conducted with the technical manager at Oloolaiser Water and Sewerage Company

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area

323 Literature reviewDifferent reports were reviewed to get information in various areas This included the past

census reports to obtain the population of people in the area Information on land use and project

location description was also obtained from the NEMA Environmental Action plan for Kajiado

Land use data was necessary to establish where the pipeline would pass

324 Government AgenciesIn order to collect topographical data a map from the Survey of Kenya was obtained for the area

This map had information on the roads contours rivers all the natural and man-made features

which were necessary for the design of the system Information on sources of water supply in the

area was also obtained from the Oloolaiser water and sewerage company who are the water

service providers in the area

325 Direct ObservationDirect observation for information on settlement and land use was necessary because of the rate

at which the town is growing This was especially needed for the land adjacent to the road

because that was where the pipeline would pass and also to consider alternative routes for the

pipeline

Page | 32

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

The following types of service connections may be distinguished

House connection

Yard connection

Group connection

Public standpipe

A house connection is a water service pipe connected with in-house plumbing to one or more

taps eg in the kitchen and bathroom Usually 38 inch (9 mm) and 12 inch (12 mm) taps are

used A typical layout is shown in figure 25

Figure 25 House connection

The service pipe is connected to the distribution main in the street by means of a T-piece on

small-diameter pipes a special insert piece or a saddle on larger-size secondary pipes A special

insert piece is mostly used for cast iron and ductile iron pipes

A yard connection is quite similar to a house connection the only difference being that the tap is

placed in the yard outside the house No in-house piping and fixtures are provided as shown

below in figure 26

Page | 18

Figure 26 Yard connection

Plastic (polyvinyl chloride or polyethylene) cast iron and galvanized steel pipes are used for

both house connections and yard connections

Group connections are outside taps that are shared by a clearly defined group of households

often neighbours Each family may pay the same (flat) share or contributions may be weighed

according to the estimated volume of water each family consumes Consumption estimates may

be based on indicators such as family size and composition and types of use by the different

households Sometimes the taps can be locked and a local committee holds the key and manages

the use and financing

Public standpipes can have one or more taps Single-tap and double-tap standpipes are the most

common types in rural areas They are made of brickwork masonry or concrete or use wooden

poles and similar materials The design should be done in close consultation with the users

(especially women) in order to arrive at an ergonomically optimal solution Standpipes may have

platforms at different levels making it easy for adults and children to use them with containers

of different sizes Examples are shown in figures 27 Cattle watering andor washing andor

bathing facilities may be constructed nearby The design and often also the construction are best

done in consultation and with participation of the user households ie both men and women

Public taps drawing from a small reservoir (cistern) represent an alternative method of water

distribution

Page | 19

Figure 27 Public Standpipes

Each standpipe should be situated at a suitable point within the community area in order to limit

the distance the water users have to go to collect their water The walking distance for the most

distant user of a standpipe should whenever possible be limited to 200 m in sparsely populated

rural areas 500 m may be acceptable The required discharge capacity of a standpipe normally is

about 14-18 litresminute at each outlet A single-tap standpipe should preferably be used by not

more than 40-70 people a multiple-tap standpipe may provide a reasonable service for up to

250-300 persons in no case should the number of users dependent on one standpipe exceed 500

Public standpipes can operate at a low pressure Distribution systems that serve only standpipes

may therefore use low pressure piping whereas the pipes for distribution systems with house

connections generally have to be of a higher pressure class Water collected at a public standpipe

will have to be carried home in a container This means that the water that was safe at the

moment of drawing may no longer be so at the moment it is used in the house Water

consumption from standpipes generally is not higher than 20-30 litres per person per day

This consumption increases when other facilities are added to reduce the amount of water

women and children have to carry home Water use for other purposes other than drinking and

cooking is likely to be curtailed when the water has to be fetched from a standpipe

Page | 20

Yard and house connections will usually encourage a more generous water use for personal

hygiene and cleaning purposes Wastage of water from standpipes can be a serious problem

especially when users fail to turn off the taps Furthermore poor drainage of spilled water may

cause stagnant pools of dirty water with the associated health hazards It is also not uncommon

for the taps to be damaged by the users and pilferage sometimes occurs These problems occur

particularly when designs do not meet the user requirements

In spite of their shortcomings group connections and public standpipes are really the only

practical options for water distribution at minimum cost to a large number of people who cannot

afford the much higher costs of house or yard connections In fact housing is frequently not

suitably constructed to allow the installation of internal plumbing It would often be impossible

for a small community to obtain the substantial capital for a water distribution system with house

connections Also the costs of adequate disposal of the considerable amounts of wastewater

generated by a house connected water supply service would place an additional heavy financial

burden on the community Consequently public standpipes have to be provided and the principal

concern should be to lessen their inherent shortcomings as much as possible (Hofkes E H et al

1981)

261 Water Demand Variation

The daily water demand in a community area will vary during the year due to seasonal climate

patterns the work situation and other factors such as cultural or religious occasions The

maximum daily demand is usually estimated by adding 10-30 to the average daily demand

Thus the peak factor for the daily water demand (k1) is 11-13

The hourly variation in domestic water demand during the day is much greater Generally two

peak periods can be observed one in the morning and one late in the afternoon as shown in fig

28 below The peak hour demand can be expressed as the average hourly demand multiplied by

the hourly peak factor (k2) For a particular distribution area this factor depends on the size and

character of the community served The hourly peak factor tends to be high for small villages It

is usually lower for larger communities and small towns Where roof tanks or other water storage

vessels are common the hourly peak factor will be further reduced

Page | 21

Usually the factor k2 is chosen in the 15-25 range Where a pipe connection is designed to

supply a small group of consumers a higher value should be adopted because of the effects of

instantaneous demand A water distribution system is typically designed to cater for the

maximum hourly demand This peak demand may then be computed as k1 x k2 x average hourly

demand (Hofkes E H et al 1981)

Figure 28 Variation of domestic water demand during the day

262 Balancing storageWithout storage of water in the distribution area the source of supply and the water treatment

plant would have to be able to follow all fluctuations in the water demand of the community

served This is generally not economical and sometimes not even technically feasible The

design capacities of the various components of a water supply system are usually chosen as

indicated

In summary

System component Design capacity

Water source Peak day water demand

Raw water main Peak day water demand

Treatment plant Peak day water demand

Page | 22

Transmission main Peak day water demand

The service reservoir is provided to balance the (constant) supply rate from the water

sourcetreatment plant with the fluctuating water demand in the distribution area The storage

volume should be large enough to accommodate the cumulative differences between water

supply and demand (Hofkes E H et al 1981)

Figure 29 Design capacities for water supply system components

263 Distribution system design

A typical range of velocities in distribution pipes is between 05 and 10 ms occasionally up to 2

ms The hydraulic gradients usually range between 1 and 5 mkm occasionally up to 10 mkm

In case of smaller pipes D lt 50 mm the hydraulic gradient can even be higher

The pressure criterion is dependent on topographic conditions availability of water at the source

and overall condition of the pipes The minimum pressures should not drop below 5-10 meter

water column In larger distribution areas where water scarcity is not an issue the minimum

pressures can range between 20 and 30 mwc above street level where there are house

connections This is sufficient for supply of 2-3 storey buildings Pressures higher than 60 mwc

Page | 23

should be avoided in general due to increased leakage and risks of bursts especially in poorly

maintained networks

After choosing a preliminary supply scheme (gravitypumping) and type of network layout

(branchedlooped) with its main components the distribution area is divided into a number of

demand districts according to the topography land use classification and density of population

Boundaries may be drawn along rivers roads high points or other features that distinguish each

district The secondary mains and distribution pipes can then be plotted on the plan

Once all the sectors are fixed the population for each district can be estimated or computed from

data collected in the community involvement process The water demand per district is then

computed using per capita water usage figures for domestic water consumption and selected

values for the other non-domestic water requirements including productive uses This per capita

usage figure may vary depending on the water service level that the community in the concerned

district has decided on (Hofkes E H et al 1981)

264 Pipes

The water from public water supply system to individual buildings is supplied through pipes A

large proportion of capital is invested on pipes while designing water supply distribution system

The following factors should be considered in selection of pipes

Strength of pipe

Water carrying capacity

Life and durability of pipe

Expenditure on transportation

Jointing process maintenance and repairs

Several different types of pipe are used in distribution systems They all have advantages and

disadvantages related to cost installation strength and corrosion The most common types of

pipe are known by their abbreviations They include Cast Iron Pipe (CIP) Ductile Iron Pipe

(DIP) Steel Pipe (ST) Asbestos-Cement Pipe (AC) Polyvinyl Chloride Pipe (PVC) and

Unplasticised Polyvinyl Chloride Pipe (UPVC)

Page | 24

UPVC (unplasticized polyvinylchloride) pipes and fittings exhibit excellent resistance to

aggressive environments both naturally occurring and as a result of industrial activity They are

resistant to almost all types of corrosion either chemical or electrochemical in nature

Since uPVC is a non-conductor galvanic and electro chemical effects do not occur in UPVC

pipes

UPVC Pipes and fittings are often used in the following circumstances

bull For drinking water pipe distribution systems both main and supply lines

bull Sewer and discharge pipe systems

Steel pipe is lighter than iron pipe and is easier to handle and install It is more flexible than iron

pipe and doesnt require as much care when bedded in the trench The main disadvantage of steel

pipe is that it is very susceptible to corrosion and should be coated both inside and outside It

doesnt have the same bearing strength that cast or ductile iron does and may collapse under

vacuum conditions Steel pipe may be joined the same way that cast is joined It may also be

joined using threaded connections (Sacramento Water Distribution System Manual 2000)

Cast iron and ductile iron pipe are known for their strength and load bearing capacity Most of

the iron pipe that has been installed in the past 40 years is ductile iron pipe Ductile iron is

stronger and less rigid than gray cast iron pipe The main disadvantages of iron pipe are that it is

heavy and subject to corrosion from the inside and the outside It should be coated with a

corrosion resistant external coating and in certain soil conditions may require some type of

cathodic protection to achieve its normal service life

Cast and ductile iron pipes can be joined by several different means Flanged joints are used

above ground The most common means of joining them underground are the bell and spigot (O-

ring push-on) and the mechanical joint (MJ) connections Care must be taken when installing and

bedding CIP and DIP are both brittle and dont flex The bell holes should only be as wide as the

bell portion of the pipe Otherwise stresses from improper bedding can cause it to crack

(Sacramento Water Distribution System Manual 2000)

Page | 25

Page | 26

2641 Pipes Appurtenances

Valves

Valves are used to control flow in a water system Most of the valves in a distribution system are

installed for isolation of sections of piping for maintenance and repair Control valves like

pressure reducing valves altitude valves pressure relief valves pressure sustaining valves and

pump control valves are designed to control pressures and throttle flows to prevent damage to the

system Air relief valves can vent trapped air from the system Check valves allow water to flow

only in one direction

Valves may be operated by hand or by actuator Actuators generally are electric and may be

operated locally or by remote control Where there is no local power supply portable power

packs may be used

Some examples of valves include

Gate Valve - Gate valves are the most common valves in a distribution system They are used for

isolation of equipment and piping They should never be used to throttle flow This will cause

damage to the valve face Open gate valves have the less friction loss than any other type of

valve Gate valves can have plug type disks or split gates Split gates are used in higher pressure

applications

Butterfly valves - Butterfly valves serve the same purpose as gate valves These valves usually

open and close with a quarter of a turn of the valve disc Larger valves will have a gear box on

the stem and will require a number of turns to open Butterfly valves are easier to open than gate

valves usually without the need for a bypass but have more friction loss when open They can

also be used for throttling flow without damaging the disc Caution should be used when filling a

line through a butterfly valve

Air Release Valve - Air release valves are used to allow air that may be trapped in the line to

escape The trapped air can create pressure and pumping problems milky-water complaints and

pressure spikes that resemble water hammer They are very useful in systems that are in hilly

country They should be located at the top of hills where the trapped air will collect

Page | 27

They are also used on booster pumps and wells to removed trapped air Combination air release

valves will also let air in when a vacuum occurs This is done to protect the piping They can also

be used to vent a line that is being drained All air-release valves should be equipped with

isolating valves for easy removal and repair of the air valves (Sacramento Water Distribution

System Manual 2000)

Section Valves - The valves should be placed in such a way that rationing of water can be done

by closing suitable parts of the supply for certain periods Whenever possible the section valves

should be placed in a joint valve chamber with air valves or washouts and upstream of these

valves In urban areas where fire-fighting is provided for there should be an isolating valve

downstream each fire hydrant (Water Design Manual 2005 Kenya)

Valve chambers

Large valves on trunk pipelines should be located in accessible chambers to facilitate

maintenance Smaller gate valves are usually buried Valve chambers should be at least 1000 x

1000mm internally There must not be UPVC-pipes within the chamber The cover should be

lockable The chamber should be drained through the floor or through a drain pipe

Hydrants

The fire insurance rates for residents on the system will be dependent in part on the proper

spacing and discharge capabilities of the fire hydrants in the system Hydrants should not be

more than 500-600 feet apart in residential districts The spacing requirements in industrial and

rural districts may vary They should be located at the end of every dead end line Hydrants

should be operated every 6 months and flow tested annually

Fire hydrants should never be placed on less than a 6 inch line if it is to be used for fire

protection In addition to provide fire protection hydrants can also be useful for flushing lines

venting lines as they are filled and pressure and flow testing Hydrants on smaller lines (4 inch

and down) will not supply enough water to fight a fire but may be used to flush dead end lines

Page | 28

Thrust Blocks

Wherever a bend elbow tee or dead-end exists in a pipeline having flexible joints a force is

exerted which tends to open the joints nearest the fittings The magnitude of this force varies

with the amount of bend the diameter of pipe and the pressure inside the pipe When

determining the resultant thrust for a given pipe it is advisable to use the maximum working

pressure anticipated in the pipe plus an allowance for surges or water hammer

Once the resultant thrust has been determined for a particular bend it becomes necessary to

provide a backing block of such size to resist the thrust The thrust must ultimately be borne by

the side of the pipe trench and the surrounding soil The purpose of the backing block is to

spread the thrust over an area sufficiently large that the undisturbed earth can support it

2642 Washouts

A washout is seldom used for scouring or washing out a main because its diameter is too small to

create sufficient flow velocity in the main to wash out debris Its principal use is for emptying a

main or for the removal of stagnant or dirty water

Primary washouts may be installed to drain to a watercourse the majority of the length between

section valves Secondary washouts of smaller diameter can then be used to empty undrained

subsections as required Sizes particularly primary washouts need to be calculated according to

the draindown time (Twort 5th Edition)

2643 Break Pressure tanks

Static head is the difference in elevation from the source to any point on the ground profile

Static head must always be considered because excessive pressure in the pipe from the elevation

head can rapture the pipe or pipe connections Piping is rated by its ability to withstand an

internal pressure without breaking The ability is a function of the type of pipe material and

thickness of the wall pipe

Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure

that will rupture the pipe or cause failures at the joints

Page | 29

The function of a break pressure tank is to allow the flow to discharge into the atmosphere

thereby reducing its hydrostatic pressure to zero and establishing a new static level A general

rule of thumb is that the static head at any given point within the conduction line should not

exceed 100m of head There is no minimum required capacity for a break pressure tank as long

as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)

Page | 30

Chapter Three

30 METHODOLOGY

31 Introduction

Different data was needed for the design of a water supply system in Ongata Rongai Methods of

data collection were established beforehand to ensure the process was efficient Once the data

was collected it was analyzed to produce an outcome that satisfied the objective of the report

The data collected included

a) Population of the area

b) Land use

c) Topographical data

d) Existing water supply

e) Information on water consumption per capita in the area

In order to obtain this data various data collection methods were used as shown below

32 Data collection methods

Various methods were employed to collect data needed for the design of the system Both

primary and secondary data was needed The quantitative methods employed were to enable me

to obtain firsthand information needed for the project These include

a) Questionnaires

b) Interviews

c) Literature review

d) Government agencies

e) Direct observation

321 QuestionnairesQuestionnaires were prepared to aid with the collection of data The questionnaires were given to

the relevant parties In order to obtain an overview of water use in the area the questionnaire was

handed to the community for a brief description on how they use the water

Page | 31

With regards to the existing water supply it was necessary to involve Oloolaiser Water with the

use of questionnaires to obtain information on their existing system

322 InterviewsIn addition to questionnaires face to face interviews were also conducted The interviews were

done to collect data on the challenges facing the existing supply of water and the sources

available for people in the area These interviews were carried out with the members living in the

project area

Information on the proposed source was also required This particular interview was conducted

with the engineer who designed the dam itself The current population of the town and the

change of boundaries in the area over the past twenty years information was obtained from an

interview conducted with the technical manager at Oloolaiser Water and Sewerage Company

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area

323 Literature reviewDifferent reports were reviewed to get information in various areas This included the past

census reports to obtain the population of people in the area Information on land use and project

location description was also obtained from the NEMA Environmental Action plan for Kajiado

Land use data was necessary to establish where the pipeline would pass

324 Government AgenciesIn order to collect topographical data a map from the Survey of Kenya was obtained for the area

This map had information on the roads contours rivers all the natural and man-made features

which were necessary for the design of the system Information on sources of water supply in the

area was also obtained from the Oloolaiser water and sewerage company who are the water

service providers in the area

325 Direct ObservationDirect observation for information on settlement and land use was necessary because of the rate

at which the town is growing This was especially needed for the land adjacent to the road

because that was where the pipeline would pass and also to consider alternative routes for the

pipeline

Page | 32

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Figure 26 Yard connection

Plastic (polyvinyl chloride or polyethylene) cast iron and galvanized steel pipes are used for

both house connections and yard connections

Group connections are outside taps that are shared by a clearly defined group of households

often neighbours Each family may pay the same (flat) share or contributions may be weighed

according to the estimated volume of water each family consumes Consumption estimates may

be based on indicators such as family size and composition and types of use by the different

households Sometimes the taps can be locked and a local committee holds the key and manages

the use and financing

Public standpipes can have one or more taps Single-tap and double-tap standpipes are the most

common types in rural areas They are made of brickwork masonry or concrete or use wooden

poles and similar materials The design should be done in close consultation with the users

(especially women) in order to arrive at an ergonomically optimal solution Standpipes may have

platforms at different levels making it easy for adults and children to use them with containers

of different sizes Examples are shown in figures 27 Cattle watering andor washing andor

bathing facilities may be constructed nearby The design and often also the construction are best

done in consultation and with participation of the user households ie both men and women

Public taps drawing from a small reservoir (cistern) represent an alternative method of water

distribution

Page | 19

Figure 27 Public Standpipes

Each standpipe should be situated at a suitable point within the community area in order to limit

the distance the water users have to go to collect their water The walking distance for the most

distant user of a standpipe should whenever possible be limited to 200 m in sparsely populated

rural areas 500 m may be acceptable The required discharge capacity of a standpipe normally is

about 14-18 litresminute at each outlet A single-tap standpipe should preferably be used by not

more than 40-70 people a multiple-tap standpipe may provide a reasonable service for up to

250-300 persons in no case should the number of users dependent on one standpipe exceed 500

Public standpipes can operate at a low pressure Distribution systems that serve only standpipes

may therefore use low pressure piping whereas the pipes for distribution systems with house

connections generally have to be of a higher pressure class Water collected at a public standpipe

will have to be carried home in a container This means that the water that was safe at the

moment of drawing may no longer be so at the moment it is used in the house Water

consumption from standpipes generally is not higher than 20-30 litres per person per day

This consumption increases when other facilities are added to reduce the amount of water

women and children have to carry home Water use for other purposes other than drinking and

cooking is likely to be curtailed when the water has to be fetched from a standpipe

Page | 20

Yard and house connections will usually encourage a more generous water use for personal

hygiene and cleaning purposes Wastage of water from standpipes can be a serious problem

especially when users fail to turn off the taps Furthermore poor drainage of spilled water may

cause stagnant pools of dirty water with the associated health hazards It is also not uncommon

for the taps to be damaged by the users and pilferage sometimes occurs These problems occur

particularly when designs do not meet the user requirements

In spite of their shortcomings group connections and public standpipes are really the only

practical options for water distribution at minimum cost to a large number of people who cannot

afford the much higher costs of house or yard connections In fact housing is frequently not

suitably constructed to allow the installation of internal plumbing It would often be impossible

for a small community to obtain the substantial capital for a water distribution system with house

connections Also the costs of adequate disposal of the considerable amounts of wastewater

generated by a house connected water supply service would place an additional heavy financial

burden on the community Consequently public standpipes have to be provided and the principal

concern should be to lessen their inherent shortcomings as much as possible (Hofkes E H et al

1981)

261 Water Demand Variation

The daily water demand in a community area will vary during the year due to seasonal climate

patterns the work situation and other factors such as cultural or religious occasions The

maximum daily demand is usually estimated by adding 10-30 to the average daily demand

Thus the peak factor for the daily water demand (k1) is 11-13

The hourly variation in domestic water demand during the day is much greater Generally two

peak periods can be observed one in the morning and one late in the afternoon as shown in fig

28 below The peak hour demand can be expressed as the average hourly demand multiplied by

the hourly peak factor (k2) For a particular distribution area this factor depends on the size and

character of the community served The hourly peak factor tends to be high for small villages It

is usually lower for larger communities and small towns Where roof tanks or other water storage

vessels are common the hourly peak factor will be further reduced

Page | 21

Usually the factor k2 is chosen in the 15-25 range Where a pipe connection is designed to

supply a small group of consumers a higher value should be adopted because of the effects of

instantaneous demand A water distribution system is typically designed to cater for the

maximum hourly demand This peak demand may then be computed as k1 x k2 x average hourly

demand (Hofkes E H et al 1981)

Figure 28 Variation of domestic water demand during the day

262 Balancing storageWithout storage of water in the distribution area the source of supply and the water treatment

plant would have to be able to follow all fluctuations in the water demand of the community

served This is generally not economical and sometimes not even technically feasible The

design capacities of the various components of a water supply system are usually chosen as

indicated

In summary

System component Design capacity

Water source Peak day water demand

Raw water main Peak day water demand

Treatment plant Peak day water demand

Page | 22

Transmission main Peak day water demand

The service reservoir is provided to balance the (constant) supply rate from the water

sourcetreatment plant with the fluctuating water demand in the distribution area The storage

volume should be large enough to accommodate the cumulative differences between water

supply and demand (Hofkes E H et al 1981)

Figure 29 Design capacities for water supply system components

263 Distribution system design

A typical range of velocities in distribution pipes is between 05 and 10 ms occasionally up to 2

ms The hydraulic gradients usually range between 1 and 5 mkm occasionally up to 10 mkm

In case of smaller pipes D lt 50 mm the hydraulic gradient can even be higher

The pressure criterion is dependent on topographic conditions availability of water at the source

and overall condition of the pipes The minimum pressures should not drop below 5-10 meter

water column In larger distribution areas where water scarcity is not an issue the minimum

pressures can range between 20 and 30 mwc above street level where there are house

connections This is sufficient for supply of 2-3 storey buildings Pressures higher than 60 mwc

Page | 23

should be avoided in general due to increased leakage and risks of bursts especially in poorly

maintained networks

After choosing a preliminary supply scheme (gravitypumping) and type of network layout

(branchedlooped) with its main components the distribution area is divided into a number of

demand districts according to the topography land use classification and density of population

Boundaries may be drawn along rivers roads high points or other features that distinguish each

district The secondary mains and distribution pipes can then be plotted on the plan

Once all the sectors are fixed the population for each district can be estimated or computed from

data collected in the community involvement process The water demand per district is then

computed using per capita water usage figures for domestic water consumption and selected

values for the other non-domestic water requirements including productive uses This per capita

usage figure may vary depending on the water service level that the community in the concerned

district has decided on (Hofkes E H et al 1981)

264 Pipes

The water from public water supply system to individual buildings is supplied through pipes A

large proportion of capital is invested on pipes while designing water supply distribution system

The following factors should be considered in selection of pipes

Strength of pipe

Water carrying capacity

Life and durability of pipe

Expenditure on transportation

Jointing process maintenance and repairs

Several different types of pipe are used in distribution systems They all have advantages and

disadvantages related to cost installation strength and corrosion The most common types of

pipe are known by their abbreviations They include Cast Iron Pipe (CIP) Ductile Iron Pipe

(DIP) Steel Pipe (ST) Asbestos-Cement Pipe (AC) Polyvinyl Chloride Pipe (PVC) and

Unplasticised Polyvinyl Chloride Pipe (UPVC)

Page | 24

UPVC (unplasticized polyvinylchloride) pipes and fittings exhibit excellent resistance to

aggressive environments both naturally occurring and as a result of industrial activity They are

resistant to almost all types of corrosion either chemical or electrochemical in nature

Since uPVC is a non-conductor galvanic and electro chemical effects do not occur in UPVC

pipes

UPVC Pipes and fittings are often used in the following circumstances

bull For drinking water pipe distribution systems both main and supply lines

bull Sewer and discharge pipe systems

Steel pipe is lighter than iron pipe and is easier to handle and install It is more flexible than iron

pipe and doesnt require as much care when bedded in the trench The main disadvantage of steel

pipe is that it is very susceptible to corrosion and should be coated both inside and outside It

doesnt have the same bearing strength that cast or ductile iron does and may collapse under

vacuum conditions Steel pipe may be joined the same way that cast is joined It may also be

joined using threaded connections (Sacramento Water Distribution System Manual 2000)

Cast iron and ductile iron pipe are known for their strength and load bearing capacity Most of

the iron pipe that has been installed in the past 40 years is ductile iron pipe Ductile iron is

stronger and less rigid than gray cast iron pipe The main disadvantages of iron pipe are that it is

heavy and subject to corrosion from the inside and the outside It should be coated with a

corrosion resistant external coating and in certain soil conditions may require some type of

cathodic protection to achieve its normal service life

Cast and ductile iron pipes can be joined by several different means Flanged joints are used

above ground The most common means of joining them underground are the bell and spigot (O-

ring push-on) and the mechanical joint (MJ) connections Care must be taken when installing and

bedding CIP and DIP are both brittle and dont flex The bell holes should only be as wide as the

bell portion of the pipe Otherwise stresses from improper bedding can cause it to crack

(Sacramento Water Distribution System Manual 2000)

Page | 25

Page | 26

2641 Pipes Appurtenances

Valves

Valves are used to control flow in a water system Most of the valves in a distribution system are

installed for isolation of sections of piping for maintenance and repair Control valves like

pressure reducing valves altitude valves pressure relief valves pressure sustaining valves and

pump control valves are designed to control pressures and throttle flows to prevent damage to the

system Air relief valves can vent trapped air from the system Check valves allow water to flow

only in one direction

Valves may be operated by hand or by actuator Actuators generally are electric and may be

operated locally or by remote control Where there is no local power supply portable power

packs may be used

Some examples of valves include

Gate Valve - Gate valves are the most common valves in a distribution system They are used for

isolation of equipment and piping They should never be used to throttle flow This will cause

damage to the valve face Open gate valves have the less friction loss than any other type of

valve Gate valves can have plug type disks or split gates Split gates are used in higher pressure

applications

Butterfly valves - Butterfly valves serve the same purpose as gate valves These valves usually

open and close with a quarter of a turn of the valve disc Larger valves will have a gear box on

the stem and will require a number of turns to open Butterfly valves are easier to open than gate

valves usually without the need for a bypass but have more friction loss when open They can

also be used for throttling flow without damaging the disc Caution should be used when filling a

line through a butterfly valve

Air Release Valve - Air release valves are used to allow air that may be trapped in the line to

escape The trapped air can create pressure and pumping problems milky-water complaints and

pressure spikes that resemble water hammer They are very useful in systems that are in hilly

country They should be located at the top of hills where the trapped air will collect

Page | 27

They are also used on booster pumps and wells to removed trapped air Combination air release

valves will also let air in when a vacuum occurs This is done to protect the piping They can also

be used to vent a line that is being drained All air-release valves should be equipped with

isolating valves for easy removal and repair of the air valves (Sacramento Water Distribution

System Manual 2000)

Section Valves - The valves should be placed in such a way that rationing of water can be done

by closing suitable parts of the supply for certain periods Whenever possible the section valves

should be placed in a joint valve chamber with air valves or washouts and upstream of these

valves In urban areas where fire-fighting is provided for there should be an isolating valve

downstream each fire hydrant (Water Design Manual 2005 Kenya)

Valve chambers

Large valves on trunk pipelines should be located in accessible chambers to facilitate

maintenance Smaller gate valves are usually buried Valve chambers should be at least 1000 x

1000mm internally There must not be UPVC-pipes within the chamber The cover should be

lockable The chamber should be drained through the floor or through a drain pipe

Hydrants

The fire insurance rates for residents on the system will be dependent in part on the proper

spacing and discharge capabilities of the fire hydrants in the system Hydrants should not be

more than 500-600 feet apart in residential districts The spacing requirements in industrial and

rural districts may vary They should be located at the end of every dead end line Hydrants

should be operated every 6 months and flow tested annually

Fire hydrants should never be placed on less than a 6 inch line if it is to be used for fire

protection In addition to provide fire protection hydrants can also be useful for flushing lines

venting lines as they are filled and pressure and flow testing Hydrants on smaller lines (4 inch

and down) will not supply enough water to fight a fire but may be used to flush dead end lines

Page | 28

Thrust Blocks

Wherever a bend elbow tee or dead-end exists in a pipeline having flexible joints a force is

exerted which tends to open the joints nearest the fittings The magnitude of this force varies

with the amount of bend the diameter of pipe and the pressure inside the pipe When

determining the resultant thrust for a given pipe it is advisable to use the maximum working

pressure anticipated in the pipe plus an allowance for surges or water hammer

Once the resultant thrust has been determined for a particular bend it becomes necessary to

provide a backing block of such size to resist the thrust The thrust must ultimately be borne by

the side of the pipe trench and the surrounding soil The purpose of the backing block is to

spread the thrust over an area sufficiently large that the undisturbed earth can support it

2642 Washouts

A washout is seldom used for scouring or washing out a main because its diameter is too small to

create sufficient flow velocity in the main to wash out debris Its principal use is for emptying a

main or for the removal of stagnant or dirty water

Primary washouts may be installed to drain to a watercourse the majority of the length between

section valves Secondary washouts of smaller diameter can then be used to empty undrained

subsections as required Sizes particularly primary washouts need to be calculated according to

the draindown time (Twort 5th Edition)

2643 Break Pressure tanks

Static head is the difference in elevation from the source to any point on the ground profile

Static head must always be considered because excessive pressure in the pipe from the elevation

head can rapture the pipe or pipe connections Piping is rated by its ability to withstand an

internal pressure without breaking The ability is a function of the type of pipe material and

thickness of the wall pipe

Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure

that will rupture the pipe or cause failures at the joints

Page | 29

The function of a break pressure tank is to allow the flow to discharge into the atmosphere

thereby reducing its hydrostatic pressure to zero and establishing a new static level A general

rule of thumb is that the static head at any given point within the conduction line should not

exceed 100m of head There is no minimum required capacity for a break pressure tank as long

as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)

Page | 30

Chapter Three

30 METHODOLOGY

31 Introduction

Different data was needed for the design of a water supply system in Ongata Rongai Methods of

data collection were established beforehand to ensure the process was efficient Once the data

was collected it was analyzed to produce an outcome that satisfied the objective of the report

The data collected included

a) Population of the area

b) Land use

c) Topographical data

d) Existing water supply

e) Information on water consumption per capita in the area

In order to obtain this data various data collection methods were used as shown below

32 Data collection methods

Various methods were employed to collect data needed for the design of the system Both

primary and secondary data was needed The quantitative methods employed were to enable me

to obtain firsthand information needed for the project These include

a) Questionnaires

b) Interviews

c) Literature review

d) Government agencies

e) Direct observation

321 QuestionnairesQuestionnaires were prepared to aid with the collection of data The questionnaires were given to

the relevant parties In order to obtain an overview of water use in the area the questionnaire was

handed to the community for a brief description on how they use the water

Page | 31

With regards to the existing water supply it was necessary to involve Oloolaiser Water with the

use of questionnaires to obtain information on their existing system

322 InterviewsIn addition to questionnaires face to face interviews were also conducted The interviews were

done to collect data on the challenges facing the existing supply of water and the sources

available for people in the area These interviews were carried out with the members living in the

project area

Information on the proposed source was also required This particular interview was conducted

with the engineer who designed the dam itself The current population of the town and the

change of boundaries in the area over the past twenty years information was obtained from an

interview conducted with the technical manager at Oloolaiser Water and Sewerage Company

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area

323 Literature reviewDifferent reports were reviewed to get information in various areas This included the past

census reports to obtain the population of people in the area Information on land use and project

location description was also obtained from the NEMA Environmental Action plan for Kajiado

Land use data was necessary to establish where the pipeline would pass

324 Government AgenciesIn order to collect topographical data a map from the Survey of Kenya was obtained for the area

This map had information on the roads contours rivers all the natural and man-made features

which were necessary for the design of the system Information on sources of water supply in the

area was also obtained from the Oloolaiser water and sewerage company who are the water

service providers in the area

325 Direct ObservationDirect observation for information on settlement and land use was necessary because of the rate

at which the town is growing This was especially needed for the land adjacent to the road

because that was where the pipeline would pass and also to consider alternative routes for the

pipeline

Page | 32

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Figure 27 Public Standpipes

Each standpipe should be situated at a suitable point within the community area in order to limit

the distance the water users have to go to collect their water The walking distance for the most

distant user of a standpipe should whenever possible be limited to 200 m in sparsely populated

rural areas 500 m may be acceptable The required discharge capacity of a standpipe normally is

about 14-18 litresminute at each outlet A single-tap standpipe should preferably be used by not

more than 40-70 people a multiple-tap standpipe may provide a reasonable service for up to

250-300 persons in no case should the number of users dependent on one standpipe exceed 500

Public standpipes can operate at a low pressure Distribution systems that serve only standpipes

may therefore use low pressure piping whereas the pipes for distribution systems with house

connections generally have to be of a higher pressure class Water collected at a public standpipe

will have to be carried home in a container This means that the water that was safe at the

moment of drawing may no longer be so at the moment it is used in the house Water

consumption from standpipes generally is not higher than 20-30 litres per person per day

This consumption increases when other facilities are added to reduce the amount of water

women and children have to carry home Water use for other purposes other than drinking and

cooking is likely to be curtailed when the water has to be fetched from a standpipe

Page | 20

Yard and house connections will usually encourage a more generous water use for personal

hygiene and cleaning purposes Wastage of water from standpipes can be a serious problem

especially when users fail to turn off the taps Furthermore poor drainage of spilled water may

cause stagnant pools of dirty water with the associated health hazards It is also not uncommon

for the taps to be damaged by the users and pilferage sometimes occurs These problems occur

particularly when designs do not meet the user requirements

In spite of their shortcomings group connections and public standpipes are really the only

practical options for water distribution at minimum cost to a large number of people who cannot

afford the much higher costs of house or yard connections In fact housing is frequently not

suitably constructed to allow the installation of internal plumbing It would often be impossible

for a small community to obtain the substantial capital for a water distribution system with house

connections Also the costs of adequate disposal of the considerable amounts of wastewater

generated by a house connected water supply service would place an additional heavy financial

burden on the community Consequently public standpipes have to be provided and the principal

concern should be to lessen their inherent shortcomings as much as possible (Hofkes E H et al

1981)

261 Water Demand Variation

The daily water demand in a community area will vary during the year due to seasonal climate

patterns the work situation and other factors such as cultural or religious occasions The

maximum daily demand is usually estimated by adding 10-30 to the average daily demand

Thus the peak factor for the daily water demand (k1) is 11-13

The hourly variation in domestic water demand during the day is much greater Generally two

peak periods can be observed one in the morning and one late in the afternoon as shown in fig

28 below The peak hour demand can be expressed as the average hourly demand multiplied by

the hourly peak factor (k2) For a particular distribution area this factor depends on the size and

character of the community served The hourly peak factor tends to be high for small villages It

is usually lower for larger communities and small towns Where roof tanks or other water storage

vessels are common the hourly peak factor will be further reduced

Page | 21

Usually the factor k2 is chosen in the 15-25 range Where a pipe connection is designed to

supply a small group of consumers a higher value should be adopted because of the effects of

instantaneous demand A water distribution system is typically designed to cater for the

maximum hourly demand This peak demand may then be computed as k1 x k2 x average hourly

demand (Hofkes E H et al 1981)

Figure 28 Variation of domestic water demand during the day

262 Balancing storageWithout storage of water in the distribution area the source of supply and the water treatment

plant would have to be able to follow all fluctuations in the water demand of the community

served This is generally not economical and sometimes not even technically feasible The

design capacities of the various components of a water supply system are usually chosen as

indicated

In summary

System component Design capacity

Water source Peak day water demand

Raw water main Peak day water demand

Treatment plant Peak day water demand

Page | 22

Transmission main Peak day water demand

The service reservoir is provided to balance the (constant) supply rate from the water

sourcetreatment plant with the fluctuating water demand in the distribution area The storage

volume should be large enough to accommodate the cumulative differences between water

supply and demand (Hofkes E H et al 1981)

Figure 29 Design capacities for water supply system components

263 Distribution system design

A typical range of velocities in distribution pipes is between 05 and 10 ms occasionally up to 2

ms The hydraulic gradients usually range between 1 and 5 mkm occasionally up to 10 mkm

In case of smaller pipes D lt 50 mm the hydraulic gradient can even be higher

The pressure criterion is dependent on topographic conditions availability of water at the source

and overall condition of the pipes The minimum pressures should not drop below 5-10 meter

water column In larger distribution areas where water scarcity is not an issue the minimum

pressures can range between 20 and 30 mwc above street level where there are house

connections This is sufficient for supply of 2-3 storey buildings Pressures higher than 60 mwc

Page | 23

should be avoided in general due to increased leakage and risks of bursts especially in poorly

maintained networks

After choosing a preliminary supply scheme (gravitypumping) and type of network layout

(branchedlooped) with its main components the distribution area is divided into a number of

demand districts according to the topography land use classification and density of population

Boundaries may be drawn along rivers roads high points or other features that distinguish each

district The secondary mains and distribution pipes can then be plotted on the plan

Once all the sectors are fixed the population for each district can be estimated or computed from

data collected in the community involvement process The water demand per district is then

computed using per capita water usage figures for domestic water consumption and selected

values for the other non-domestic water requirements including productive uses This per capita

usage figure may vary depending on the water service level that the community in the concerned

district has decided on (Hofkes E H et al 1981)

264 Pipes

The water from public water supply system to individual buildings is supplied through pipes A

large proportion of capital is invested on pipes while designing water supply distribution system

The following factors should be considered in selection of pipes

Strength of pipe

Water carrying capacity

Life and durability of pipe

Expenditure on transportation

Jointing process maintenance and repairs

Several different types of pipe are used in distribution systems They all have advantages and

disadvantages related to cost installation strength and corrosion The most common types of

pipe are known by their abbreviations They include Cast Iron Pipe (CIP) Ductile Iron Pipe

(DIP) Steel Pipe (ST) Asbestos-Cement Pipe (AC) Polyvinyl Chloride Pipe (PVC) and

Unplasticised Polyvinyl Chloride Pipe (UPVC)

Page | 24

UPVC (unplasticized polyvinylchloride) pipes and fittings exhibit excellent resistance to

aggressive environments both naturally occurring and as a result of industrial activity They are

resistant to almost all types of corrosion either chemical or electrochemical in nature

Since uPVC is a non-conductor galvanic and electro chemical effects do not occur in UPVC

pipes

UPVC Pipes and fittings are often used in the following circumstances

bull For drinking water pipe distribution systems both main and supply lines

bull Sewer and discharge pipe systems

Steel pipe is lighter than iron pipe and is easier to handle and install It is more flexible than iron

pipe and doesnt require as much care when bedded in the trench The main disadvantage of steel

pipe is that it is very susceptible to corrosion and should be coated both inside and outside It

doesnt have the same bearing strength that cast or ductile iron does and may collapse under

vacuum conditions Steel pipe may be joined the same way that cast is joined It may also be

joined using threaded connections (Sacramento Water Distribution System Manual 2000)

Cast iron and ductile iron pipe are known for their strength and load bearing capacity Most of

the iron pipe that has been installed in the past 40 years is ductile iron pipe Ductile iron is

stronger and less rigid than gray cast iron pipe The main disadvantages of iron pipe are that it is

heavy and subject to corrosion from the inside and the outside It should be coated with a

corrosion resistant external coating and in certain soil conditions may require some type of

cathodic protection to achieve its normal service life

Cast and ductile iron pipes can be joined by several different means Flanged joints are used

above ground The most common means of joining them underground are the bell and spigot (O-

ring push-on) and the mechanical joint (MJ) connections Care must be taken when installing and

bedding CIP and DIP are both brittle and dont flex The bell holes should only be as wide as the

bell portion of the pipe Otherwise stresses from improper bedding can cause it to crack

(Sacramento Water Distribution System Manual 2000)

Page | 25

Page | 26

2641 Pipes Appurtenances

Valves

Valves are used to control flow in a water system Most of the valves in a distribution system are

installed for isolation of sections of piping for maintenance and repair Control valves like

pressure reducing valves altitude valves pressure relief valves pressure sustaining valves and

pump control valves are designed to control pressures and throttle flows to prevent damage to the

system Air relief valves can vent trapped air from the system Check valves allow water to flow

only in one direction

Valves may be operated by hand or by actuator Actuators generally are electric and may be

operated locally or by remote control Where there is no local power supply portable power

packs may be used

Some examples of valves include

Gate Valve - Gate valves are the most common valves in a distribution system They are used for

isolation of equipment and piping They should never be used to throttle flow This will cause

damage to the valve face Open gate valves have the less friction loss than any other type of

valve Gate valves can have plug type disks or split gates Split gates are used in higher pressure

applications

Butterfly valves - Butterfly valves serve the same purpose as gate valves These valves usually

open and close with a quarter of a turn of the valve disc Larger valves will have a gear box on

the stem and will require a number of turns to open Butterfly valves are easier to open than gate

valves usually without the need for a bypass but have more friction loss when open They can

also be used for throttling flow without damaging the disc Caution should be used when filling a

line through a butterfly valve

Air Release Valve - Air release valves are used to allow air that may be trapped in the line to

escape The trapped air can create pressure and pumping problems milky-water complaints and

pressure spikes that resemble water hammer They are very useful in systems that are in hilly

country They should be located at the top of hills where the trapped air will collect

Page | 27

They are also used on booster pumps and wells to removed trapped air Combination air release

valves will also let air in when a vacuum occurs This is done to protect the piping They can also

be used to vent a line that is being drained All air-release valves should be equipped with

isolating valves for easy removal and repair of the air valves (Sacramento Water Distribution

System Manual 2000)

Section Valves - The valves should be placed in such a way that rationing of water can be done

by closing suitable parts of the supply for certain periods Whenever possible the section valves

should be placed in a joint valve chamber with air valves or washouts and upstream of these

valves In urban areas where fire-fighting is provided for there should be an isolating valve

downstream each fire hydrant (Water Design Manual 2005 Kenya)

Valve chambers

Large valves on trunk pipelines should be located in accessible chambers to facilitate

maintenance Smaller gate valves are usually buried Valve chambers should be at least 1000 x

1000mm internally There must not be UPVC-pipes within the chamber The cover should be

lockable The chamber should be drained through the floor or through a drain pipe

Hydrants

The fire insurance rates for residents on the system will be dependent in part on the proper

spacing and discharge capabilities of the fire hydrants in the system Hydrants should not be

more than 500-600 feet apart in residential districts The spacing requirements in industrial and

rural districts may vary They should be located at the end of every dead end line Hydrants

should be operated every 6 months and flow tested annually

Fire hydrants should never be placed on less than a 6 inch line if it is to be used for fire

protection In addition to provide fire protection hydrants can also be useful for flushing lines

venting lines as they are filled and pressure and flow testing Hydrants on smaller lines (4 inch

and down) will not supply enough water to fight a fire but may be used to flush dead end lines

Page | 28

Thrust Blocks

Wherever a bend elbow tee or dead-end exists in a pipeline having flexible joints a force is

exerted which tends to open the joints nearest the fittings The magnitude of this force varies

with the amount of bend the diameter of pipe and the pressure inside the pipe When

determining the resultant thrust for a given pipe it is advisable to use the maximum working

pressure anticipated in the pipe plus an allowance for surges or water hammer

Once the resultant thrust has been determined for a particular bend it becomes necessary to

provide a backing block of such size to resist the thrust The thrust must ultimately be borne by

the side of the pipe trench and the surrounding soil The purpose of the backing block is to

spread the thrust over an area sufficiently large that the undisturbed earth can support it

2642 Washouts

A washout is seldom used for scouring or washing out a main because its diameter is too small to

create sufficient flow velocity in the main to wash out debris Its principal use is for emptying a

main or for the removal of stagnant or dirty water

Primary washouts may be installed to drain to a watercourse the majority of the length between

section valves Secondary washouts of smaller diameter can then be used to empty undrained

subsections as required Sizes particularly primary washouts need to be calculated according to

the draindown time (Twort 5th Edition)

2643 Break Pressure tanks

Static head is the difference in elevation from the source to any point on the ground profile

Static head must always be considered because excessive pressure in the pipe from the elevation

head can rapture the pipe or pipe connections Piping is rated by its ability to withstand an

internal pressure without breaking The ability is a function of the type of pipe material and

thickness of the wall pipe

Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure

that will rupture the pipe or cause failures at the joints

Page | 29

The function of a break pressure tank is to allow the flow to discharge into the atmosphere

thereby reducing its hydrostatic pressure to zero and establishing a new static level A general

rule of thumb is that the static head at any given point within the conduction line should not

exceed 100m of head There is no minimum required capacity for a break pressure tank as long

as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)

Page | 30

Chapter Three

30 METHODOLOGY

31 Introduction

Different data was needed for the design of a water supply system in Ongata Rongai Methods of

data collection were established beforehand to ensure the process was efficient Once the data

was collected it was analyzed to produce an outcome that satisfied the objective of the report

The data collected included

a) Population of the area

b) Land use

c) Topographical data

d) Existing water supply

e) Information on water consumption per capita in the area

In order to obtain this data various data collection methods were used as shown below

32 Data collection methods

Various methods were employed to collect data needed for the design of the system Both

primary and secondary data was needed The quantitative methods employed were to enable me

to obtain firsthand information needed for the project These include

a) Questionnaires

b) Interviews

c) Literature review

d) Government agencies

e) Direct observation

321 QuestionnairesQuestionnaires were prepared to aid with the collection of data The questionnaires were given to

the relevant parties In order to obtain an overview of water use in the area the questionnaire was

handed to the community for a brief description on how they use the water

Page | 31

With regards to the existing water supply it was necessary to involve Oloolaiser Water with the

use of questionnaires to obtain information on their existing system

322 InterviewsIn addition to questionnaires face to face interviews were also conducted The interviews were

done to collect data on the challenges facing the existing supply of water and the sources

available for people in the area These interviews were carried out with the members living in the

project area

Information on the proposed source was also required This particular interview was conducted

with the engineer who designed the dam itself The current population of the town and the

change of boundaries in the area over the past twenty years information was obtained from an

interview conducted with the technical manager at Oloolaiser Water and Sewerage Company

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area

323 Literature reviewDifferent reports were reviewed to get information in various areas This included the past

census reports to obtain the population of people in the area Information on land use and project

location description was also obtained from the NEMA Environmental Action plan for Kajiado

Land use data was necessary to establish where the pipeline would pass

324 Government AgenciesIn order to collect topographical data a map from the Survey of Kenya was obtained for the area

This map had information on the roads contours rivers all the natural and man-made features

which were necessary for the design of the system Information on sources of water supply in the

area was also obtained from the Oloolaiser water and sewerage company who are the water

service providers in the area

325 Direct ObservationDirect observation for information on settlement and land use was necessary because of the rate

at which the town is growing This was especially needed for the land adjacent to the road

because that was where the pipeline would pass and also to consider alternative routes for the

pipeline

Page | 32

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Yard and house connections will usually encourage a more generous water use for personal

hygiene and cleaning purposes Wastage of water from standpipes can be a serious problem

especially when users fail to turn off the taps Furthermore poor drainage of spilled water may

cause stagnant pools of dirty water with the associated health hazards It is also not uncommon

for the taps to be damaged by the users and pilferage sometimes occurs These problems occur

particularly when designs do not meet the user requirements

In spite of their shortcomings group connections and public standpipes are really the only

practical options for water distribution at minimum cost to a large number of people who cannot

afford the much higher costs of house or yard connections In fact housing is frequently not

suitably constructed to allow the installation of internal plumbing It would often be impossible

for a small community to obtain the substantial capital for a water distribution system with house

connections Also the costs of adequate disposal of the considerable amounts of wastewater

generated by a house connected water supply service would place an additional heavy financial

burden on the community Consequently public standpipes have to be provided and the principal

concern should be to lessen their inherent shortcomings as much as possible (Hofkes E H et al

1981)

261 Water Demand Variation

The daily water demand in a community area will vary during the year due to seasonal climate

patterns the work situation and other factors such as cultural or religious occasions The

maximum daily demand is usually estimated by adding 10-30 to the average daily demand

Thus the peak factor for the daily water demand (k1) is 11-13

The hourly variation in domestic water demand during the day is much greater Generally two

peak periods can be observed one in the morning and one late in the afternoon as shown in fig

28 below The peak hour demand can be expressed as the average hourly demand multiplied by

the hourly peak factor (k2) For a particular distribution area this factor depends on the size and

character of the community served The hourly peak factor tends to be high for small villages It

is usually lower for larger communities and small towns Where roof tanks or other water storage

vessels are common the hourly peak factor will be further reduced

Page | 21

Usually the factor k2 is chosen in the 15-25 range Where a pipe connection is designed to

supply a small group of consumers a higher value should be adopted because of the effects of

instantaneous demand A water distribution system is typically designed to cater for the

maximum hourly demand This peak demand may then be computed as k1 x k2 x average hourly

demand (Hofkes E H et al 1981)

Figure 28 Variation of domestic water demand during the day

262 Balancing storageWithout storage of water in the distribution area the source of supply and the water treatment

plant would have to be able to follow all fluctuations in the water demand of the community

served This is generally not economical and sometimes not even technically feasible The

design capacities of the various components of a water supply system are usually chosen as

indicated

In summary

System component Design capacity

Water source Peak day water demand

Raw water main Peak day water demand

Treatment plant Peak day water demand

Page | 22

Transmission main Peak day water demand

The service reservoir is provided to balance the (constant) supply rate from the water

sourcetreatment plant with the fluctuating water demand in the distribution area The storage

volume should be large enough to accommodate the cumulative differences between water

supply and demand (Hofkes E H et al 1981)

Figure 29 Design capacities for water supply system components

263 Distribution system design

A typical range of velocities in distribution pipes is between 05 and 10 ms occasionally up to 2

ms The hydraulic gradients usually range between 1 and 5 mkm occasionally up to 10 mkm

In case of smaller pipes D lt 50 mm the hydraulic gradient can even be higher

The pressure criterion is dependent on topographic conditions availability of water at the source

and overall condition of the pipes The minimum pressures should not drop below 5-10 meter

water column In larger distribution areas where water scarcity is not an issue the minimum

pressures can range between 20 and 30 mwc above street level where there are house

connections This is sufficient for supply of 2-3 storey buildings Pressures higher than 60 mwc

Page | 23

should be avoided in general due to increased leakage and risks of bursts especially in poorly

maintained networks

After choosing a preliminary supply scheme (gravitypumping) and type of network layout

(branchedlooped) with its main components the distribution area is divided into a number of

demand districts according to the topography land use classification and density of population

Boundaries may be drawn along rivers roads high points or other features that distinguish each

district The secondary mains and distribution pipes can then be plotted on the plan

Once all the sectors are fixed the population for each district can be estimated or computed from

data collected in the community involvement process The water demand per district is then

computed using per capita water usage figures for domestic water consumption and selected

values for the other non-domestic water requirements including productive uses This per capita

usage figure may vary depending on the water service level that the community in the concerned

district has decided on (Hofkes E H et al 1981)

264 Pipes

The water from public water supply system to individual buildings is supplied through pipes A

large proportion of capital is invested on pipes while designing water supply distribution system

The following factors should be considered in selection of pipes

Strength of pipe

Water carrying capacity

Life and durability of pipe

Expenditure on transportation

Jointing process maintenance and repairs

Several different types of pipe are used in distribution systems They all have advantages and

disadvantages related to cost installation strength and corrosion The most common types of

pipe are known by their abbreviations They include Cast Iron Pipe (CIP) Ductile Iron Pipe

(DIP) Steel Pipe (ST) Asbestos-Cement Pipe (AC) Polyvinyl Chloride Pipe (PVC) and

Unplasticised Polyvinyl Chloride Pipe (UPVC)

Page | 24

UPVC (unplasticized polyvinylchloride) pipes and fittings exhibit excellent resistance to

aggressive environments both naturally occurring and as a result of industrial activity They are

resistant to almost all types of corrosion either chemical or electrochemical in nature

Since uPVC is a non-conductor galvanic and electro chemical effects do not occur in UPVC

pipes

UPVC Pipes and fittings are often used in the following circumstances

bull For drinking water pipe distribution systems both main and supply lines

bull Sewer and discharge pipe systems

Steel pipe is lighter than iron pipe and is easier to handle and install It is more flexible than iron

pipe and doesnt require as much care when bedded in the trench The main disadvantage of steel

pipe is that it is very susceptible to corrosion and should be coated both inside and outside It

doesnt have the same bearing strength that cast or ductile iron does and may collapse under

vacuum conditions Steel pipe may be joined the same way that cast is joined It may also be

joined using threaded connections (Sacramento Water Distribution System Manual 2000)

Cast iron and ductile iron pipe are known for their strength and load bearing capacity Most of

the iron pipe that has been installed in the past 40 years is ductile iron pipe Ductile iron is

stronger and less rigid than gray cast iron pipe The main disadvantages of iron pipe are that it is

heavy and subject to corrosion from the inside and the outside It should be coated with a

corrosion resistant external coating and in certain soil conditions may require some type of

cathodic protection to achieve its normal service life

Cast and ductile iron pipes can be joined by several different means Flanged joints are used

above ground The most common means of joining them underground are the bell and spigot (O-

ring push-on) and the mechanical joint (MJ) connections Care must be taken when installing and

bedding CIP and DIP are both brittle and dont flex The bell holes should only be as wide as the

bell portion of the pipe Otherwise stresses from improper bedding can cause it to crack

(Sacramento Water Distribution System Manual 2000)

Page | 25

Page | 26

2641 Pipes Appurtenances

Valves

Valves are used to control flow in a water system Most of the valves in a distribution system are

installed for isolation of sections of piping for maintenance and repair Control valves like

pressure reducing valves altitude valves pressure relief valves pressure sustaining valves and

pump control valves are designed to control pressures and throttle flows to prevent damage to the

system Air relief valves can vent trapped air from the system Check valves allow water to flow

only in one direction

Valves may be operated by hand or by actuator Actuators generally are electric and may be

operated locally or by remote control Where there is no local power supply portable power

packs may be used

Some examples of valves include

Gate Valve - Gate valves are the most common valves in a distribution system They are used for

isolation of equipment and piping They should never be used to throttle flow This will cause

damage to the valve face Open gate valves have the less friction loss than any other type of

valve Gate valves can have plug type disks or split gates Split gates are used in higher pressure

applications

Butterfly valves - Butterfly valves serve the same purpose as gate valves These valves usually

open and close with a quarter of a turn of the valve disc Larger valves will have a gear box on

the stem and will require a number of turns to open Butterfly valves are easier to open than gate

valves usually without the need for a bypass but have more friction loss when open They can

also be used for throttling flow without damaging the disc Caution should be used when filling a

line through a butterfly valve

Air Release Valve - Air release valves are used to allow air that may be trapped in the line to

escape The trapped air can create pressure and pumping problems milky-water complaints and

pressure spikes that resemble water hammer They are very useful in systems that are in hilly

country They should be located at the top of hills where the trapped air will collect

Page | 27

They are also used on booster pumps and wells to removed trapped air Combination air release

valves will also let air in when a vacuum occurs This is done to protect the piping They can also

be used to vent a line that is being drained All air-release valves should be equipped with

isolating valves for easy removal and repair of the air valves (Sacramento Water Distribution

System Manual 2000)

Section Valves - The valves should be placed in such a way that rationing of water can be done

by closing suitable parts of the supply for certain periods Whenever possible the section valves

should be placed in a joint valve chamber with air valves or washouts and upstream of these

valves In urban areas where fire-fighting is provided for there should be an isolating valve

downstream each fire hydrant (Water Design Manual 2005 Kenya)

Valve chambers

Large valves on trunk pipelines should be located in accessible chambers to facilitate

maintenance Smaller gate valves are usually buried Valve chambers should be at least 1000 x

1000mm internally There must not be UPVC-pipes within the chamber The cover should be

lockable The chamber should be drained through the floor or through a drain pipe

Hydrants

The fire insurance rates for residents on the system will be dependent in part on the proper

spacing and discharge capabilities of the fire hydrants in the system Hydrants should not be

more than 500-600 feet apart in residential districts The spacing requirements in industrial and

rural districts may vary They should be located at the end of every dead end line Hydrants

should be operated every 6 months and flow tested annually

Fire hydrants should never be placed on less than a 6 inch line if it is to be used for fire

protection In addition to provide fire protection hydrants can also be useful for flushing lines

venting lines as they are filled and pressure and flow testing Hydrants on smaller lines (4 inch

and down) will not supply enough water to fight a fire but may be used to flush dead end lines

Page | 28

Thrust Blocks

Wherever a bend elbow tee or dead-end exists in a pipeline having flexible joints a force is

exerted which tends to open the joints nearest the fittings The magnitude of this force varies

with the amount of bend the diameter of pipe and the pressure inside the pipe When

determining the resultant thrust for a given pipe it is advisable to use the maximum working

pressure anticipated in the pipe plus an allowance for surges or water hammer

Once the resultant thrust has been determined for a particular bend it becomes necessary to

provide a backing block of such size to resist the thrust The thrust must ultimately be borne by

the side of the pipe trench and the surrounding soil The purpose of the backing block is to

spread the thrust over an area sufficiently large that the undisturbed earth can support it

2642 Washouts

A washout is seldom used for scouring or washing out a main because its diameter is too small to

create sufficient flow velocity in the main to wash out debris Its principal use is for emptying a

main or for the removal of stagnant or dirty water

Primary washouts may be installed to drain to a watercourse the majority of the length between

section valves Secondary washouts of smaller diameter can then be used to empty undrained

subsections as required Sizes particularly primary washouts need to be calculated according to

the draindown time (Twort 5th Edition)

2643 Break Pressure tanks

Static head is the difference in elevation from the source to any point on the ground profile

Static head must always be considered because excessive pressure in the pipe from the elevation

head can rapture the pipe or pipe connections Piping is rated by its ability to withstand an

internal pressure without breaking The ability is a function of the type of pipe material and

thickness of the wall pipe

Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure

that will rupture the pipe or cause failures at the joints

Page | 29

The function of a break pressure tank is to allow the flow to discharge into the atmosphere

thereby reducing its hydrostatic pressure to zero and establishing a new static level A general

rule of thumb is that the static head at any given point within the conduction line should not

exceed 100m of head There is no minimum required capacity for a break pressure tank as long

as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)

Page | 30

Chapter Three

30 METHODOLOGY

31 Introduction

Different data was needed for the design of a water supply system in Ongata Rongai Methods of

data collection were established beforehand to ensure the process was efficient Once the data

was collected it was analyzed to produce an outcome that satisfied the objective of the report

The data collected included

a) Population of the area

b) Land use

c) Topographical data

d) Existing water supply

e) Information on water consumption per capita in the area

In order to obtain this data various data collection methods were used as shown below

32 Data collection methods

Various methods were employed to collect data needed for the design of the system Both

primary and secondary data was needed The quantitative methods employed were to enable me

to obtain firsthand information needed for the project These include

a) Questionnaires

b) Interviews

c) Literature review

d) Government agencies

e) Direct observation

321 QuestionnairesQuestionnaires were prepared to aid with the collection of data The questionnaires were given to

the relevant parties In order to obtain an overview of water use in the area the questionnaire was

handed to the community for a brief description on how they use the water

Page | 31

With regards to the existing water supply it was necessary to involve Oloolaiser Water with the

use of questionnaires to obtain information on their existing system

322 InterviewsIn addition to questionnaires face to face interviews were also conducted The interviews were

done to collect data on the challenges facing the existing supply of water and the sources

available for people in the area These interviews were carried out with the members living in the

project area

Information on the proposed source was also required This particular interview was conducted

with the engineer who designed the dam itself The current population of the town and the

change of boundaries in the area over the past twenty years information was obtained from an

interview conducted with the technical manager at Oloolaiser Water and Sewerage Company

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area

323 Literature reviewDifferent reports were reviewed to get information in various areas This included the past

census reports to obtain the population of people in the area Information on land use and project

location description was also obtained from the NEMA Environmental Action plan for Kajiado

Land use data was necessary to establish where the pipeline would pass

324 Government AgenciesIn order to collect topographical data a map from the Survey of Kenya was obtained for the area

This map had information on the roads contours rivers all the natural and man-made features

which were necessary for the design of the system Information on sources of water supply in the

area was also obtained from the Oloolaiser water and sewerage company who are the water

service providers in the area

325 Direct ObservationDirect observation for information on settlement and land use was necessary because of the rate

at which the town is growing This was especially needed for the land adjacent to the road

because that was where the pipeline would pass and also to consider alternative routes for the

pipeline

Page | 32

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Usually the factor k2 is chosen in the 15-25 range Where a pipe connection is designed to

supply a small group of consumers a higher value should be adopted because of the effects of

instantaneous demand A water distribution system is typically designed to cater for the

maximum hourly demand This peak demand may then be computed as k1 x k2 x average hourly

demand (Hofkes E H et al 1981)

Figure 28 Variation of domestic water demand during the day

262 Balancing storageWithout storage of water in the distribution area the source of supply and the water treatment

plant would have to be able to follow all fluctuations in the water demand of the community

served This is generally not economical and sometimes not even technically feasible The

design capacities of the various components of a water supply system are usually chosen as

indicated

In summary

System component Design capacity

Water source Peak day water demand

Raw water main Peak day water demand

Treatment plant Peak day water demand

Page | 22

Transmission main Peak day water demand

The service reservoir is provided to balance the (constant) supply rate from the water

sourcetreatment plant with the fluctuating water demand in the distribution area The storage

volume should be large enough to accommodate the cumulative differences between water

supply and demand (Hofkes E H et al 1981)

Figure 29 Design capacities for water supply system components

263 Distribution system design

A typical range of velocities in distribution pipes is between 05 and 10 ms occasionally up to 2

ms The hydraulic gradients usually range between 1 and 5 mkm occasionally up to 10 mkm

In case of smaller pipes D lt 50 mm the hydraulic gradient can even be higher

The pressure criterion is dependent on topographic conditions availability of water at the source

and overall condition of the pipes The minimum pressures should not drop below 5-10 meter

water column In larger distribution areas where water scarcity is not an issue the minimum

pressures can range between 20 and 30 mwc above street level where there are house

connections This is sufficient for supply of 2-3 storey buildings Pressures higher than 60 mwc

Page | 23

should be avoided in general due to increased leakage and risks of bursts especially in poorly

maintained networks

After choosing a preliminary supply scheme (gravitypumping) and type of network layout

(branchedlooped) with its main components the distribution area is divided into a number of

demand districts according to the topography land use classification and density of population

Boundaries may be drawn along rivers roads high points or other features that distinguish each

district The secondary mains and distribution pipes can then be plotted on the plan

Once all the sectors are fixed the population for each district can be estimated or computed from

data collected in the community involvement process The water demand per district is then

computed using per capita water usage figures for domestic water consumption and selected

values for the other non-domestic water requirements including productive uses This per capita

usage figure may vary depending on the water service level that the community in the concerned

district has decided on (Hofkes E H et al 1981)

264 Pipes

The water from public water supply system to individual buildings is supplied through pipes A

large proportion of capital is invested on pipes while designing water supply distribution system

The following factors should be considered in selection of pipes

Strength of pipe

Water carrying capacity

Life and durability of pipe

Expenditure on transportation

Jointing process maintenance and repairs

Several different types of pipe are used in distribution systems They all have advantages and

disadvantages related to cost installation strength and corrosion The most common types of

pipe are known by their abbreviations They include Cast Iron Pipe (CIP) Ductile Iron Pipe

(DIP) Steel Pipe (ST) Asbestos-Cement Pipe (AC) Polyvinyl Chloride Pipe (PVC) and

Unplasticised Polyvinyl Chloride Pipe (UPVC)

Page | 24

UPVC (unplasticized polyvinylchloride) pipes and fittings exhibit excellent resistance to

aggressive environments both naturally occurring and as a result of industrial activity They are

resistant to almost all types of corrosion either chemical or electrochemical in nature

Since uPVC is a non-conductor galvanic and electro chemical effects do not occur in UPVC

pipes

UPVC Pipes and fittings are often used in the following circumstances

bull For drinking water pipe distribution systems both main and supply lines

bull Sewer and discharge pipe systems

Steel pipe is lighter than iron pipe and is easier to handle and install It is more flexible than iron

pipe and doesnt require as much care when bedded in the trench The main disadvantage of steel

pipe is that it is very susceptible to corrosion and should be coated both inside and outside It

doesnt have the same bearing strength that cast or ductile iron does and may collapse under

vacuum conditions Steel pipe may be joined the same way that cast is joined It may also be

joined using threaded connections (Sacramento Water Distribution System Manual 2000)

Cast iron and ductile iron pipe are known for their strength and load bearing capacity Most of

the iron pipe that has been installed in the past 40 years is ductile iron pipe Ductile iron is

stronger and less rigid than gray cast iron pipe The main disadvantages of iron pipe are that it is

heavy and subject to corrosion from the inside and the outside It should be coated with a

corrosion resistant external coating and in certain soil conditions may require some type of

cathodic protection to achieve its normal service life

Cast and ductile iron pipes can be joined by several different means Flanged joints are used

above ground The most common means of joining them underground are the bell and spigot (O-

ring push-on) and the mechanical joint (MJ) connections Care must be taken when installing and

bedding CIP and DIP are both brittle and dont flex The bell holes should only be as wide as the

bell portion of the pipe Otherwise stresses from improper bedding can cause it to crack

(Sacramento Water Distribution System Manual 2000)

Page | 25

Page | 26

2641 Pipes Appurtenances

Valves

Valves are used to control flow in a water system Most of the valves in a distribution system are

installed for isolation of sections of piping for maintenance and repair Control valves like

pressure reducing valves altitude valves pressure relief valves pressure sustaining valves and

pump control valves are designed to control pressures and throttle flows to prevent damage to the

system Air relief valves can vent trapped air from the system Check valves allow water to flow

only in one direction

Valves may be operated by hand or by actuator Actuators generally are electric and may be

operated locally or by remote control Where there is no local power supply portable power

packs may be used

Some examples of valves include

Gate Valve - Gate valves are the most common valves in a distribution system They are used for

isolation of equipment and piping They should never be used to throttle flow This will cause

damage to the valve face Open gate valves have the less friction loss than any other type of

valve Gate valves can have plug type disks or split gates Split gates are used in higher pressure

applications

Butterfly valves - Butterfly valves serve the same purpose as gate valves These valves usually

open and close with a quarter of a turn of the valve disc Larger valves will have a gear box on

the stem and will require a number of turns to open Butterfly valves are easier to open than gate

valves usually without the need for a bypass but have more friction loss when open They can

also be used for throttling flow without damaging the disc Caution should be used when filling a

line through a butterfly valve

Air Release Valve - Air release valves are used to allow air that may be trapped in the line to

escape The trapped air can create pressure and pumping problems milky-water complaints and

pressure spikes that resemble water hammer They are very useful in systems that are in hilly

country They should be located at the top of hills where the trapped air will collect

Page | 27

They are also used on booster pumps and wells to removed trapped air Combination air release

valves will also let air in when a vacuum occurs This is done to protect the piping They can also

be used to vent a line that is being drained All air-release valves should be equipped with

isolating valves for easy removal and repair of the air valves (Sacramento Water Distribution

System Manual 2000)

Section Valves - The valves should be placed in such a way that rationing of water can be done

by closing suitable parts of the supply for certain periods Whenever possible the section valves

should be placed in a joint valve chamber with air valves or washouts and upstream of these

valves In urban areas where fire-fighting is provided for there should be an isolating valve

downstream each fire hydrant (Water Design Manual 2005 Kenya)

Valve chambers

Large valves on trunk pipelines should be located in accessible chambers to facilitate

maintenance Smaller gate valves are usually buried Valve chambers should be at least 1000 x

1000mm internally There must not be UPVC-pipes within the chamber The cover should be

lockable The chamber should be drained through the floor or through a drain pipe

Hydrants

The fire insurance rates for residents on the system will be dependent in part on the proper

spacing and discharge capabilities of the fire hydrants in the system Hydrants should not be

more than 500-600 feet apart in residential districts The spacing requirements in industrial and

rural districts may vary They should be located at the end of every dead end line Hydrants

should be operated every 6 months and flow tested annually

Fire hydrants should never be placed on less than a 6 inch line if it is to be used for fire

protection In addition to provide fire protection hydrants can also be useful for flushing lines

venting lines as they are filled and pressure and flow testing Hydrants on smaller lines (4 inch

and down) will not supply enough water to fight a fire but may be used to flush dead end lines

Page | 28

Thrust Blocks

Wherever a bend elbow tee or dead-end exists in a pipeline having flexible joints a force is

exerted which tends to open the joints nearest the fittings The magnitude of this force varies

with the amount of bend the diameter of pipe and the pressure inside the pipe When

determining the resultant thrust for a given pipe it is advisable to use the maximum working

pressure anticipated in the pipe plus an allowance for surges or water hammer

Once the resultant thrust has been determined for a particular bend it becomes necessary to

provide a backing block of such size to resist the thrust The thrust must ultimately be borne by

the side of the pipe trench and the surrounding soil The purpose of the backing block is to

spread the thrust over an area sufficiently large that the undisturbed earth can support it

2642 Washouts

A washout is seldom used for scouring or washing out a main because its diameter is too small to

create sufficient flow velocity in the main to wash out debris Its principal use is for emptying a

main or for the removal of stagnant or dirty water

Primary washouts may be installed to drain to a watercourse the majority of the length between

section valves Secondary washouts of smaller diameter can then be used to empty undrained

subsections as required Sizes particularly primary washouts need to be calculated according to

the draindown time (Twort 5th Edition)

2643 Break Pressure tanks

Static head is the difference in elevation from the source to any point on the ground profile

Static head must always be considered because excessive pressure in the pipe from the elevation

head can rapture the pipe or pipe connections Piping is rated by its ability to withstand an

internal pressure without breaking The ability is a function of the type of pipe material and

thickness of the wall pipe

Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure

that will rupture the pipe or cause failures at the joints

Page | 29

The function of a break pressure tank is to allow the flow to discharge into the atmosphere

thereby reducing its hydrostatic pressure to zero and establishing a new static level A general

rule of thumb is that the static head at any given point within the conduction line should not

exceed 100m of head There is no minimum required capacity for a break pressure tank as long

as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)

Page | 30

Chapter Three

30 METHODOLOGY

31 Introduction

Different data was needed for the design of a water supply system in Ongata Rongai Methods of

data collection were established beforehand to ensure the process was efficient Once the data

was collected it was analyzed to produce an outcome that satisfied the objective of the report

The data collected included

a) Population of the area

b) Land use

c) Topographical data

d) Existing water supply

e) Information on water consumption per capita in the area

In order to obtain this data various data collection methods were used as shown below

32 Data collection methods

Various methods were employed to collect data needed for the design of the system Both

primary and secondary data was needed The quantitative methods employed were to enable me

to obtain firsthand information needed for the project These include

a) Questionnaires

b) Interviews

c) Literature review

d) Government agencies

e) Direct observation

321 QuestionnairesQuestionnaires were prepared to aid with the collection of data The questionnaires were given to

the relevant parties In order to obtain an overview of water use in the area the questionnaire was

handed to the community for a brief description on how they use the water

Page | 31

With regards to the existing water supply it was necessary to involve Oloolaiser Water with the

use of questionnaires to obtain information on their existing system

322 InterviewsIn addition to questionnaires face to face interviews were also conducted The interviews were

done to collect data on the challenges facing the existing supply of water and the sources

available for people in the area These interviews were carried out with the members living in the

project area

Information on the proposed source was also required This particular interview was conducted

with the engineer who designed the dam itself The current population of the town and the

change of boundaries in the area over the past twenty years information was obtained from an

interview conducted with the technical manager at Oloolaiser Water and Sewerage Company

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area

323 Literature reviewDifferent reports were reviewed to get information in various areas This included the past

census reports to obtain the population of people in the area Information on land use and project

location description was also obtained from the NEMA Environmental Action plan for Kajiado

Land use data was necessary to establish where the pipeline would pass

324 Government AgenciesIn order to collect topographical data a map from the Survey of Kenya was obtained for the area

This map had information on the roads contours rivers all the natural and man-made features

which were necessary for the design of the system Information on sources of water supply in the

area was also obtained from the Oloolaiser water and sewerage company who are the water

service providers in the area

325 Direct ObservationDirect observation for information on settlement and land use was necessary because of the rate

at which the town is growing This was especially needed for the land adjacent to the road

because that was where the pipeline would pass and also to consider alternative routes for the

pipeline

Page | 32

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Transmission main Peak day water demand

The service reservoir is provided to balance the (constant) supply rate from the water

sourcetreatment plant with the fluctuating water demand in the distribution area The storage

volume should be large enough to accommodate the cumulative differences between water

supply and demand (Hofkes E H et al 1981)

Figure 29 Design capacities for water supply system components

263 Distribution system design

A typical range of velocities in distribution pipes is between 05 and 10 ms occasionally up to 2

ms The hydraulic gradients usually range between 1 and 5 mkm occasionally up to 10 mkm

In case of smaller pipes D lt 50 mm the hydraulic gradient can even be higher

The pressure criterion is dependent on topographic conditions availability of water at the source

and overall condition of the pipes The minimum pressures should not drop below 5-10 meter

water column In larger distribution areas where water scarcity is not an issue the minimum

pressures can range between 20 and 30 mwc above street level where there are house

connections This is sufficient for supply of 2-3 storey buildings Pressures higher than 60 mwc

Page | 23

should be avoided in general due to increased leakage and risks of bursts especially in poorly

maintained networks

After choosing a preliminary supply scheme (gravitypumping) and type of network layout

(branchedlooped) with its main components the distribution area is divided into a number of

demand districts according to the topography land use classification and density of population

Boundaries may be drawn along rivers roads high points or other features that distinguish each

district The secondary mains and distribution pipes can then be plotted on the plan

Once all the sectors are fixed the population for each district can be estimated or computed from

data collected in the community involvement process The water demand per district is then

computed using per capita water usage figures for domestic water consumption and selected

values for the other non-domestic water requirements including productive uses This per capita

usage figure may vary depending on the water service level that the community in the concerned

district has decided on (Hofkes E H et al 1981)

264 Pipes

The water from public water supply system to individual buildings is supplied through pipes A

large proportion of capital is invested on pipes while designing water supply distribution system

The following factors should be considered in selection of pipes

Strength of pipe

Water carrying capacity

Life and durability of pipe

Expenditure on transportation

Jointing process maintenance and repairs

Several different types of pipe are used in distribution systems They all have advantages and

disadvantages related to cost installation strength and corrosion The most common types of

pipe are known by their abbreviations They include Cast Iron Pipe (CIP) Ductile Iron Pipe

(DIP) Steel Pipe (ST) Asbestos-Cement Pipe (AC) Polyvinyl Chloride Pipe (PVC) and

Unplasticised Polyvinyl Chloride Pipe (UPVC)

Page | 24

UPVC (unplasticized polyvinylchloride) pipes and fittings exhibit excellent resistance to

aggressive environments both naturally occurring and as a result of industrial activity They are

resistant to almost all types of corrosion either chemical or electrochemical in nature

Since uPVC is a non-conductor galvanic and electro chemical effects do not occur in UPVC

pipes

UPVC Pipes and fittings are often used in the following circumstances

bull For drinking water pipe distribution systems both main and supply lines

bull Sewer and discharge pipe systems

Steel pipe is lighter than iron pipe and is easier to handle and install It is more flexible than iron

pipe and doesnt require as much care when bedded in the trench The main disadvantage of steel

pipe is that it is very susceptible to corrosion and should be coated both inside and outside It

doesnt have the same bearing strength that cast or ductile iron does and may collapse under

vacuum conditions Steel pipe may be joined the same way that cast is joined It may also be

joined using threaded connections (Sacramento Water Distribution System Manual 2000)

Cast iron and ductile iron pipe are known for their strength and load bearing capacity Most of

the iron pipe that has been installed in the past 40 years is ductile iron pipe Ductile iron is

stronger and less rigid than gray cast iron pipe The main disadvantages of iron pipe are that it is

heavy and subject to corrosion from the inside and the outside It should be coated with a

corrosion resistant external coating and in certain soil conditions may require some type of

cathodic protection to achieve its normal service life

Cast and ductile iron pipes can be joined by several different means Flanged joints are used

above ground The most common means of joining them underground are the bell and spigot (O-

ring push-on) and the mechanical joint (MJ) connections Care must be taken when installing and

bedding CIP and DIP are both brittle and dont flex The bell holes should only be as wide as the

bell portion of the pipe Otherwise stresses from improper bedding can cause it to crack

(Sacramento Water Distribution System Manual 2000)

Page | 25

Page | 26

2641 Pipes Appurtenances

Valves

Valves are used to control flow in a water system Most of the valves in a distribution system are

installed for isolation of sections of piping for maintenance and repair Control valves like

pressure reducing valves altitude valves pressure relief valves pressure sustaining valves and

pump control valves are designed to control pressures and throttle flows to prevent damage to the

system Air relief valves can vent trapped air from the system Check valves allow water to flow

only in one direction

Valves may be operated by hand or by actuator Actuators generally are electric and may be

operated locally or by remote control Where there is no local power supply portable power

packs may be used

Some examples of valves include

Gate Valve - Gate valves are the most common valves in a distribution system They are used for

isolation of equipment and piping They should never be used to throttle flow This will cause

damage to the valve face Open gate valves have the less friction loss than any other type of

valve Gate valves can have plug type disks or split gates Split gates are used in higher pressure

applications

Butterfly valves - Butterfly valves serve the same purpose as gate valves These valves usually

open and close with a quarter of a turn of the valve disc Larger valves will have a gear box on

the stem and will require a number of turns to open Butterfly valves are easier to open than gate

valves usually without the need for a bypass but have more friction loss when open They can

also be used for throttling flow without damaging the disc Caution should be used when filling a

line through a butterfly valve

Air Release Valve - Air release valves are used to allow air that may be trapped in the line to

escape The trapped air can create pressure and pumping problems milky-water complaints and

pressure spikes that resemble water hammer They are very useful in systems that are in hilly

country They should be located at the top of hills where the trapped air will collect

Page | 27

They are also used on booster pumps and wells to removed trapped air Combination air release

valves will also let air in when a vacuum occurs This is done to protect the piping They can also

be used to vent a line that is being drained All air-release valves should be equipped with

isolating valves for easy removal and repair of the air valves (Sacramento Water Distribution

System Manual 2000)

Section Valves - The valves should be placed in such a way that rationing of water can be done

by closing suitable parts of the supply for certain periods Whenever possible the section valves

should be placed in a joint valve chamber with air valves or washouts and upstream of these

valves In urban areas where fire-fighting is provided for there should be an isolating valve

downstream each fire hydrant (Water Design Manual 2005 Kenya)

Valve chambers

Large valves on trunk pipelines should be located in accessible chambers to facilitate

maintenance Smaller gate valves are usually buried Valve chambers should be at least 1000 x

1000mm internally There must not be UPVC-pipes within the chamber The cover should be

lockable The chamber should be drained through the floor or through a drain pipe

Hydrants

The fire insurance rates for residents on the system will be dependent in part on the proper

spacing and discharge capabilities of the fire hydrants in the system Hydrants should not be

more than 500-600 feet apart in residential districts The spacing requirements in industrial and

rural districts may vary They should be located at the end of every dead end line Hydrants

should be operated every 6 months and flow tested annually

Fire hydrants should never be placed on less than a 6 inch line if it is to be used for fire

protection In addition to provide fire protection hydrants can also be useful for flushing lines

venting lines as they are filled and pressure and flow testing Hydrants on smaller lines (4 inch

and down) will not supply enough water to fight a fire but may be used to flush dead end lines

Page | 28

Thrust Blocks

Wherever a bend elbow tee or dead-end exists in a pipeline having flexible joints a force is

exerted which tends to open the joints nearest the fittings The magnitude of this force varies

with the amount of bend the diameter of pipe and the pressure inside the pipe When

determining the resultant thrust for a given pipe it is advisable to use the maximum working

pressure anticipated in the pipe plus an allowance for surges or water hammer

Once the resultant thrust has been determined for a particular bend it becomes necessary to

provide a backing block of such size to resist the thrust The thrust must ultimately be borne by

the side of the pipe trench and the surrounding soil The purpose of the backing block is to

spread the thrust over an area sufficiently large that the undisturbed earth can support it

2642 Washouts

A washout is seldom used for scouring or washing out a main because its diameter is too small to

create sufficient flow velocity in the main to wash out debris Its principal use is for emptying a

main or for the removal of stagnant or dirty water

Primary washouts may be installed to drain to a watercourse the majority of the length between

section valves Secondary washouts of smaller diameter can then be used to empty undrained

subsections as required Sizes particularly primary washouts need to be calculated according to

the draindown time (Twort 5th Edition)

2643 Break Pressure tanks

Static head is the difference in elevation from the source to any point on the ground profile

Static head must always be considered because excessive pressure in the pipe from the elevation

head can rapture the pipe or pipe connections Piping is rated by its ability to withstand an

internal pressure without breaking The ability is a function of the type of pipe material and

thickness of the wall pipe

Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure

that will rupture the pipe or cause failures at the joints

Page | 29

The function of a break pressure tank is to allow the flow to discharge into the atmosphere

thereby reducing its hydrostatic pressure to zero and establishing a new static level A general

rule of thumb is that the static head at any given point within the conduction line should not

exceed 100m of head There is no minimum required capacity for a break pressure tank as long

as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)

Page | 30

Chapter Three

30 METHODOLOGY

31 Introduction

Different data was needed for the design of a water supply system in Ongata Rongai Methods of

data collection were established beforehand to ensure the process was efficient Once the data

was collected it was analyzed to produce an outcome that satisfied the objective of the report

The data collected included

a) Population of the area

b) Land use

c) Topographical data

d) Existing water supply

e) Information on water consumption per capita in the area

In order to obtain this data various data collection methods were used as shown below

32 Data collection methods

Various methods were employed to collect data needed for the design of the system Both

primary and secondary data was needed The quantitative methods employed were to enable me

to obtain firsthand information needed for the project These include

a) Questionnaires

b) Interviews

c) Literature review

d) Government agencies

e) Direct observation

321 QuestionnairesQuestionnaires were prepared to aid with the collection of data The questionnaires were given to

the relevant parties In order to obtain an overview of water use in the area the questionnaire was

handed to the community for a brief description on how they use the water

Page | 31

With regards to the existing water supply it was necessary to involve Oloolaiser Water with the

use of questionnaires to obtain information on their existing system

322 InterviewsIn addition to questionnaires face to face interviews were also conducted The interviews were

done to collect data on the challenges facing the existing supply of water and the sources

available for people in the area These interviews were carried out with the members living in the

project area

Information on the proposed source was also required This particular interview was conducted

with the engineer who designed the dam itself The current population of the town and the

change of boundaries in the area over the past twenty years information was obtained from an

interview conducted with the technical manager at Oloolaiser Water and Sewerage Company

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area

323 Literature reviewDifferent reports were reviewed to get information in various areas This included the past

census reports to obtain the population of people in the area Information on land use and project

location description was also obtained from the NEMA Environmental Action plan for Kajiado

Land use data was necessary to establish where the pipeline would pass

324 Government AgenciesIn order to collect topographical data a map from the Survey of Kenya was obtained for the area

This map had information on the roads contours rivers all the natural and man-made features

which were necessary for the design of the system Information on sources of water supply in the

area was also obtained from the Oloolaiser water and sewerage company who are the water

service providers in the area

325 Direct ObservationDirect observation for information on settlement and land use was necessary because of the rate

at which the town is growing This was especially needed for the land adjacent to the road

because that was where the pipeline would pass and also to consider alternative routes for the

pipeline

Page | 32

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

should be avoided in general due to increased leakage and risks of bursts especially in poorly

maintained networks

After choosing a preliminary supply scheme (gravitypumping) and type of network layout

(branchedlooped) with its main components the distribution area is divided into a number of

demand districts according to the topography land use classification and density of population

Boundaries may be drawn along rivers roads high points or other features that distinguish each

district The secondary mains and distribution pipes can then be plotted on the plan

Once all the sectors are fixed the population for each district can be estimated or computed from

data collected in the community involvement process The water demand per district is then

computed using per capita water usage figures for domestic water consumption and selected

values for the other non-domestic water requirements including productive uses This per capita

usage figure may vary depending on the water service level that the community in the concerned

district has decided on (Hofkes E H et al 1981)

264 Pipes

The water from public water supply system to individual buildings is supplied through pipes A

large proportion of capital is invested on pipes while designing water supply distribution system

The following factors should be considered in selection of pipes

Strength of pipe

Water carrying capacity

Life and durability of pipe

Expenditure on transportation

Jointing process maintenance and repairs

Several different types of pipe are used in distribution systems They all have advantages and

disadvantages related to cost installation strength and corrosion The most common types of

pipe are known by their abbreviations They include Cast Iron Pipe (CIP) Ductile Iron Pipe

(DIP) Steel Pipe (ST) Asbestos-Cement Pipe (AC) Polyvinyl Chloride Pipe (PVC) and

Unplasticised Polyvinyl Chloride Pipe (UPVC)

Page | 24

UPVC (unplasticized polyvinylchloride) pipes and fittings exhibit excellent resistance to

aggressive environments both naturally occurring and as a result of industrial activity They are

resistant to almost all types of corrosion either chemical or electrochemical in nature

Since uPVC is a non-conductor galvanic and electro chemical effects do not occur in UPVC

pipes

UPVC Pipes and fittings are often used in the following circumstances

bull For drinking water pipe distribution systems both main and supply lines

bull Sewer and discharge pipe systems

Steel pipe is lighter than iron pipe and is easier to handle and install It is more flexible than iron

pipe and doesnt require as much care when bedded in the trench The main disadvantage of steel

pipe is that it is very susceptible to corrosion and should be coated both inside and outside It

doesnt have the same bearing strength that cast or ductile iron does and may collapse under

vacuum conditions Steel pipe may be joined the same way that cast is joined It may also be

joined using threaded connections (Sacramento Water Distribution System Manual 2000)

Cast iron and ductile iron pipe are known for their strength and load bearing capacity Most of

the iron pipe that has been installed in the past 40 years is ductile iron pipe Ductile iron is

stronger and less rigid than gray cast iron pipe The main disadvantages of iron pipe are that it is

heavy and subject to corrosion from the inside and the outside It should be coated with a

corrosion resistant external coating and in certain soil conditions may require some type of

cathodic protection to achieve its normal service life

Cast and ductile iron pipes can be joined by several different means Flanged joints are used

above ground The most common means of joining them underground are the bell and spigot (O-

ring push-on) and the mechanical joint (MJ) connections Care must be taken when installing and

bedding CIP and DIP are both brittle and dont flex The bell holes should only be as wide as the

bell portion of the pipe Otherwise stresses from improper bedding can cause it to crack

(Sacramento Water Distribution System Manual 2000)

Page | 25

Page | 26

2641 Pipes Appurtenances

Valves

Valves are used to control flow in a water system Most of the valves in a distribution system are

installed for isolation of sections of piping for maintenance and repair Control valves like

pressure reducing valves altitude valves pressure relief valves pressure sustaining valves and

pump control valves are designed to control pressures and throttle flows to prevent damage to the

system Air relief valves can vent trapped air from the system Check valves allow water to flow

only in one direction

Valves may be operated by hand or by actuator Actuators generally are electric and may be

operated locally or by remote control Where there is no local power supply portable power

packs may be used

Some examples of valves include

Gate Valve - Gate valves are the most common valves in a distribution system They are used for

isolation of equipment and piping They should never be used to throttle flow This will cause

damage to the valve face Open gate valves have the less friction loss than any other type of

valve Gate valves can have plug type disks or split gates Split gates are used in higher pressure

applications

Butterfly valves - Butterfly valves serve the same purpose as gate valves These valves usually

open and close with a quarter of a turn of the valve disc Larger valves will have a gear box on

the stem and will require a number of turns to open Butterfly valves are easier to open than gate

valves usually without the need for a bypass but have more friction loss when open They can

also be used for throttling flow without damaging the disc Caution should be used when filling a

line through a butterfly valve

Air Release Valve - Air release valves are used to allow air that may be trapped in the line to

escape The trapped air can create pressure and pumping problems milky-water complaints and

pressure spikes that resemble water hammer They are very useful in systems that are in hilly

country They should be located at the top of hills where the trapped air will collect

Page | 27

They are also used on booster pumps and wells to removed trapped air Combination air release

valves will also let air in when a vacuum occurs This is done to protect the piping They can also

be used to vent a line that is being drained All air-release valves should be equipped with

isolating valves for easy removal and repair of the air valves (Sacramento Water Distribution

System Manual 2000)

Section Valves - The valves should be placed in such a way that rationing of water can be done

by closing suitable parts of the supply for certain periods Whenever possible the section valves

should be placed in a joint valve chamber with air valves or washouts and upstream of these

valves In urban areas where fire-fighting is provided for there should be an isolating valve

downstream each fire hydrant (Water Design Manual 2005 Kenya)

Valve chambers

Large valves on trunk pipelines should be located in accessible chambers to facilitate

maintenance Smaller gate valves are usually buried Valve chambers should be at least 1000 x

1000mm internally There must not be UPVC-pipes within the chamber The cover should be

lockable The chamber should be drained through the floor or through a drain pipe

Hydrants

The fire insurance rates for residents on the system will be dependent in part on the proper

spacing and discharge capabilities of the fire hydrants in the system Hydrants should not be

more than 500-600 feet apart in residential districts The spacing requirements in industrial and

rural districts may vary They should be located at the end of every dead end line Hydrants

should be operated every 6 months and flow tested annually

Fire hydrants should never be placed on less than a 6 inch line if it is to be used for fire

protection In addition to provide fire protection hydrants can also be useful for flushing lines

venting lines as they are filled and pressure and flow testing Hydrants on smaller lines (4 inch

and down) will not supply enough water to fight a fire but may be used to flush dead end lines

Page | 28

Thrust Blocks

Wherever a bend elbow tee or dead-end exists in a pipeline having flexible joints a force is

exerted which tends to open the joints nearest the fittings The magnitude of this force varies

with the amount of bend the diameter of pipe and the pressure inside the pipe When

determining the resultant thrust for a given pipe it is advisable to use the maximum working

pressure anticipated in the pipe plus an allowance for surges or water hammer

Once the resultant thrust has been determined for a particular bend it becomes necessary to

provide a backing block of such size to resist the thrust The thrust must ultimately be borne by

the side of the pipe trench and the surrounding soil The purpose of the backing block is to

spread the thrust over an area sufficiently large that the undisturbed earth can support it

2642 Washouts

A washout is seldom used for scouring or washing out a main because its diameter is too small to

create sufficient flow velocity in the main to wash out debris Its principal use is for emptying a

main or for the removal of stagnant or dirty water

Primary washouts may be installed to drain to a watercourse the majority of the length between

section valves Secondary washouts of smaller diameter can then be used to empty undrained

subsections as required Sizes particularly primary washouts need to be calculated according to

the draindown time (Twort 5th Edition)

2643 Break Pressure tanks

Static head is the difference in elevation from the source to any point on the ground profile

Static head must always be considered because excessive pressure in the pipe from the elevation

head can rapture the pipe or pipe connections Piping is rated by its ability to withstand an

internal pressure without breaking The ability is a function of the type of pipe material and

thickness of the wall pipe

Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure

that will rupture the pipe or cause failures at the joints

Page | 29

The function of a break pressure tank is to allow the flow to discharge into the atmosphere

thereby reducing its hydrostatic pressure to zero and establishing a new static level A general

rule of thumb is that the static head at any given point within the conduction line should not

exceed 100m of head There is no minimum required capacity for a break pressure tank as long

as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)

Page | 30

Chapter Three

30 METHODOLOGY

31 Introduction

Different data was needed for the design of a water supply system in Ongata Rongai Methods of

data collection were established beforehand to ensure the process was efficient Once the data

was collected it was analyzed to produce an outcome that satisfied the objective of the report

The data collected included

a) Population of the area

b) Land use

c) Topographical data

d) Existing water supply

e) Information on water consumption per capita in the area

In order to obtain this data various data collection methods were used as shown below

32 Data collection methods

Various methods were employed to collect data needed for the design of the system Both

primary and secondary data was needed The quantitative methods employed were to enable me

to obtain firsthand information needed for the project These include

a) Questionnaires

b) Interviews

c) Literature review

d) Government agencies

e) Direct observation

321 QuestionnairesQuestionnaires were prepared to aid with the collection of data The questionnaires were given to

the relevant parties In order to obtain an overview of water use in the area the questionnaire was

handed to the community for a brief description on how they use the water

Page | 31

With regards to the existing water supply it was necessary to involve Oloolaiser Water with the

use of questionnaires to obtain information on their existing system

322 InterviewsIn addition to questionnaires face to face interviews were also conducted The interviews were

done to collect data on the challenges facing the existing supply of water and the sources

available for people in the area These interviews were carried out with the members living in the

project area

Information on the proposed source was also required This particular interview was conducted

with the engineer who designed the dam itself The current population of the town and the

change of boundaries in the area over the past twenty years information was obtained from an

interview conducted with the technical manager at Oloolaiser Water and Sewerage Company

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area

323 Literature reviewDifferent reports were reviewed to get information in various areas This included the past

census reports to obtain the population of people in the area Information on land use and project

location description was also obtained from the NEMA Environmental Action plan for Kajiado

Land use data was necessary to establish where the pipeline would pass

324 Government AgenciesIn order to collect topographical data a map from the Survey of Kenya was obtained for the area

This map had information on the roads contours rivers all the natural and man-made features

which were necessary for the design of the system Information on sources of water supply in the

area was also obtained from the Oloolaiser water and sewerage company who are the water

service providers in the area

325 Direct ObservationDirect observation for information on settlement and land use was necessary because of the rate

at which the town is growing This was especially needed for the land adjacent to the road

because that was where the pipeline would pass and also to consider alternative routes for the

pipeline

Page | 32

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

UPVC (unplasticized polyvinylchloride) pipes and fittings exhibit excellent resistance to

aggressive environments both naturally occurring and as a result of industrial activity They are

resistant to almost all types of corrosion either chemical or electrochemical in nature

Since uPVC is a non-conductor galvanic and electro chemical effects do not occur in UPVC

pipes

UPVC Pipes and fittings are often used in the following circumstances

bull For drinking water pipe distribution systems both main and supply lines

bull Sewer and discharge pipe systems

Steel pipe is lighter than iron pipe and is easier to handle and install It is more flexible than iron

pipe and doesnt require as much care when bedded in the trench The main disadvantage of steel

pipe is that it is very susceptible to corrosion and should be coated both inside and outside It

doesnt have the same bearing strength that cast or ductile iron does and may collapse under

vacuum conditions Steel pipe may be joined the same way that cast is joined It may also be

joined using threaded connections (Sacramento Water Distribution System Manual 2000)

Cast iron and ductile iron pipe are known for their strength and load bearing capacity Most of

the iron pipe that has been installed in the past 40 years is ductile iron pipe Ductile iron is

stronger and less rigid than gray cast iron pipe The main disadvantages of iron pipe are that it is

heavy and subject to corrosion from the inside and the outside It should be coated with a

corrosion resistant external coating and in certain soil conditions may require some type of

cathodic protection to achieve its normal service life

Cast and ductile iron pipes can be joined by several different means Flanged joints are used

above ground The most common means of joining them underground are the bell and spigot (O-

ring push-on) and the mechanical joint (MJ) connections Care must be taken when installing and

bedding CIP and DIP are both brittle and dont flex The bell holes should only be as wide as the

bell portion of the pipe Otherwise stresses from improper bedding can cause it to crack

(Sacramento Water Distribution System Manual 2000)

Page | 25

Page | 26

2641 Pipes Appurtenances

Valves

Valves are used to control flow in a water system Most of the valves in a distribution system are

installed for isolation of sections of piping for maintenance and repair Control valves like

pressure reducing valves altitude valves pressure relief valves pressure sustaining valves and

pump control valves are designed to control pressures and throttle flows to prevent damage to the

system Air relief valves can vent trapped air from the system Check valves allow water to flow

only in one direction

Valves may be operated by hand or by actuator Actuators generally are electric and may be

operated locally or by remote control Where there is no local power supply portable power

packs may be used

Some examples of valves include

Gate Valve - Gate valves are the most common valves in a distribution system They are used for

isolation of equipment and piping They should never be used to throttle flow This will cause

damage to the valve face Open gate valves have the less friction loss than any other type of

valve Gate valves can have plug type disks or split gates Split gates are used in higher pressure

applications

Butterfly valves - Butterfly valves serve the same purpose as gate valves These valves usually

open and close with a quarter of a turn of the valve disc Larger valves will have a gear box on

the stem and will require a number of turns to open Butterfly valves are easier to open than gate

valves usually without the need for a bypass but have more friction loss when open They can

also be used for throttling flow without damaging the disc Caution should be used when filling a

line through a butterfly valve

Air Release Valve - Air release valves are used to allow air that may be trapped in the line to

escape The trapped air can create pressure and pumping problems milky-water complaints and

pressure spikes that resemble water hammer They are very useful in systems that are in hilly

country They should be located at the top of hills where the trapped air will collect

Page | 27

They are also used on booster pumps and wells to removed trapped air Combination air release

valves will also let air in when a vacuum occurs This is done to protect the piping They can also

be used to vent a line that is being drained All air-release valves should be equipped with

isolating valves for easy removal and repair of the air valves (Sacramento Water Distribution

System Manual 2000)

Section Valves - The valves should be placed in such a way that rationing of water can be done

by closing suitable parts of the supply for certain periods Whenever possible the section valves

should be placed in a joint valve chamber with air valves or washouts and upstream of these

valves In urban areas where fire-fighting is provided for there should be an isolating valve

downstream each fire hydrant (Water Design Manual 2005 Kenya)

Valve chambers

Large valves on trunk pipelines should be located in accessible chambers to facilitate

maintenance Smaller gate valves are usually buried Valve chambers should be at least 1000 x

1000mm internally There must not be UPVC-pipes within the chamber The cover should be

lockable The chamber should be drained through the floor or through a drain pipe

Hydrants

The fire insurance rates for residents on the system will be dependent in part on the proper

spacing and discharge capabilities of the fire hydrants in the system Hydrants should not be

more than 500-600 feet apart in residential districts The spacing requirements in industrial and

rural districts may vary They should be located at the end of every dead end line Hydrants

should be operated every 6 months and flow tested annually

Fire hydrants should never be placed on less than a 6 inch line if it is to be used for fire

protection In addition to provide fire protection hydrants can also be useful for flushing lines

venting lines as they are filled and pressure and flow testing Hydrants on smaller lines (4 inch

and down) will not supply enough water to fight a fire but may be used to flush dead end lines

Page | 28

Thrust Blocks

Wherever a bend elbow tee or dead-end exists in a pipeline having flexible joints a force is

exerted which tends to open the joints nearest the fittings The magnitude of this force varies

with the amount of bend the diameter of pipe and the pressure inside the pipe When

determining the resultant thrust for a given pipe it is advisable to use the maximum working

pressure anticipated in the pipe plus an allowance for surges or water hammer

Once the resultant thrust has been determined for a particular bend it becomes necessary to

provide a backing block of such size to resist the thrust The thrust must ultimately be borne by

the side of the pipe trench and the surrounding soil The purpose of the backing block is to

spread the thrust over an area sufficiently large that the undisturbed earth can support it

2642 Washouts

A washout is seldom used for scouring or washing out a main because its diameter is too small to

create sufficient flow velocity in the main to wash out debris Its principal use is for emptying a

main or for the removal of stagnant or dirty water

Primary washouts may be installed to drain to a watercourse the majority of the length between

section valves Secondary washouts of smaller diameter can then be used to empty undrained

subsections as required Sizes particularly primary washouts need to be calculated according to

the draindown time (Twort 5th Edition)

2643 Break Pressure tanks

Static head is the difference in elevation from the source to any point on the ground profile

Static head must always be considered because excessive pressure in the pipe from the elevation

head can rapture the pipe or pipe connections Piping is rated by its ability to withstand an

internal pressure without breaking The ability is a function of the type of pipe material and

thickness of the wall pipe

Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure

that will rupture the pipe or cause failures at the joints

Page | 29

The function of a break pressure tank is to allow the flow to discharge into the atmosphere

thereby reducing its hydrostatic pressure to zero and establishing a new static level A general

rule of thumb is that the static head at any given point within the conduction line should not

exceed 100m of head There is no minimum required capacity for a break pressure tank as long

as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)

Page | 30

Chapter Three

30 METHODOLOGY

31 Introduction

Different data was needed for the design of a water supply system in Ongata Rongai Methods of

data collection were established beforehand to ensure the process was efficient Once the data

was collected it was analyzed to produce an outcome that satisfied the objective of the report

The data collected included

a) Population of the area

b) Land use

c) Topographical data

d) Existing water supply

e) Information on water consumption per capita in the area

In order to obtain this data various data collection methods were used as shown below

32 Data collection methods

Various methods were employed to collect data needed for the design of the system Both

primary and secondary data was needed The quantitative methods employed were to enable me

to obtain firsthand information needed for the project These include

a) Questionnaires

b) Interviews

c) Literature review

d) Government agencies

e) Direct observation

321 QuestionnairesQuestionnaires were prepared to aid with the collection of data The questionnaires were given to

the relevant parties In order to obtain an overview of water use in the area the questionnaire was

handed to the community for a brief description on how they use the water

Page | 31

With regards to the existing water supply it was necessary to involve Oloolaiser Water with the

use of questionnaires to obtain information on their existing system

322 InterviewsIn addition to questionnaires face to face interviews were also conducted The interviews were

done to collect data on the challenges facing the existing supply of water and the sources

available for people in the area These interviews were carried out with the members living in the

project area

Information on the proposed source was also required This particular interview was conducted

with the engineer who designed the dam itself The current population of the town and the

change of boundaries in the area over the past twenty years information was obtained from an

interview conducted with the technical manager at Oloolaiser Water and Sewerage Company

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area

323 Literature reviewDifferent reports were reviewed to get information in various areas This included the past

census reports to obtain the population of people in the area Information on land use and project

location description was also obtained from the NEMA Environmental Action plan for Kajiado

Land use data was necessary to establish where the pipeline would pass

324 Government AgenciesIn order to collect topographical data a map from the Survey of Kenya was obtained for the area

This map had information on the roads contours rivers all the natural and man-made features

which were necessary for the design of the system Information on sources of water supply in the

area was also obtained from the Oloolaiser water and sewerage company who are the water

service providers in the area

325 Direct ObservationDirect observation for information on settlement and land use was necessary because of the rate

at which the town is growing This was especially needed for the land adjacent to the road

because that was where the pipeline would pass and also to consider alternative routes for the

pipeline

Page | 32

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Page | 26

2641 Pipes Appurtenances

Valves

Valves are used to control flow in a water system Most of the valves in a distribution system are

installed for isolation of sections of piping for maintenance and repair Control valves like

pressure reducing valves altitude valves pressure relief valves pressure sustaining valves and

pump control valves are designed to control pressures and throttle flows to prevent damage to the

system Air relief valves can vent trapped air from the system Check valves allow water to flow

only in one direction

Valves may be operated by hand or by actuator Actuators generally are electric and may be

operated locally or by remote control Where there is no local power supply portable power

packs may be used

Some examples of valves include

Gate Valve - Gate valves are the most common valves in a distribution system They are used for

isolation of equipment and piping They should never be used to throttle flow This will cause

damage to the valve face Open gate valves have the less friction loss than any other type of

valve Gate valves can have plug type disks or split gates Split gates are used in higher pressure

applications

Butterfly valves - Butterfly valves serve the same purpose as gate valves These valves usually

open and close with a quarter of a turn of the valve disc Larger valves will have a gear box on

the stem and will require a number of turns to open Butterfly valves are easier to open than gate

valves usually without the need for a bypass but have more friction loss when open They can

also be used for throttling flow without damaging the disc Caution should be used when filling a

line through a butterfly valve

Air Release Valve - Air release valves are used to allow air that may be trapped in the line to

escape The trapped air can create pressure and pumping problems milky-water complaints and

pressure spikes that resemble water hammer They are very useful in systems that are in hilly

country They should be located at the top of hills where the trapped air will collect

Page | 27

They are also used on booster pumps and wells to removed trapped air Combination air release

valves will also let air in when a vacuum occurs This is done to protect the piping They can also

be used to vent a line that is being drained All air-release valves should be equipped with

isolating valves for easy removal and repair of the air valves (Sacramento Water Distribution

System Manual 2000)

Section Valves - The valves should be placed in such a way that rationing of water can be done

by closing suitable parts of the supply for certain periods Whenever possible the section valves

should be placed in a joint valve chamber with air valves or washouts and upstream of these

valves In urban areas where fire-fighting is provided for there should be an isolating valve

downstream each fire hydrant (Water Design Manual 2005 Kenya)

Valve chambers

Large valves on trunk pipelines should be located in accessible chambers to facilitate

maintenance Smaller gate valves are usually buried Valve chambers should be at least 1000 x

1000mm internally There must not be UPVC-pipes within the chamber The cover should be

lockable The chamber should be drained through the floor or through a drain pipe

Hydrants

The fire insurance rates for residents on the system will be dependent in part on the proper

spacing and discharge capabilities of the fire hydrants in the system Hydrants should not be

more than 500-600 feet apart in residential districts The spacing requirements in industrial and

rural districts may vary They should be located at the end of every dead end line Hydrants

should be operated every 6 months and flow tested annually

Fire hydrants should never be placed on less than a 6 inch line if it is to be used for fire

protection In addition to provide fire protection hydrants can also be useful for flushing lines

venting lines as they are filled and pressure and flow testing Hydrants on smaller lines (4 inch

and down) will not supply enough water to fight a fire but may be used to flush dead end lines

Page | 28

Thrust Blocks

Wherever a bend elbow tee or dead-end exists in a pipeline having flexible joints a force is

exerted which tends to open the joints nearest the fittings The magnitude of this force varies

with the amount of bend the diameter of pipe and the pressure inside the pipe When

determining the resultant thrust for a given pipe it is advisable to use the maximum working

pressure anticipated in the pipe plus an allowance for surges or water hammer

Once the resultant thrust has been determined for a particular bend it becomes necessary to

provide a backing block of such size to resist the thrust The thrust must ultimately be borne by

the side of the pipe trench and the surrounding soil The purpose of the backing block is to

spread the thrust over an area sufficiently large that the undisturbed earth can support it

2642 Washouts

A washout is seldom used for scouring or washing out a main because its diameter is too small to

create sufficient flow velocity in the main to wash out debris Its principal use is for emptying a

main or for the removal of stagnant or dirty water

Primary washouts may be installed to drain to a watercourse the majority of the length between

section valves Secondary washouts of smaller diameter can then be used to empty undrained

subsections as required Sizes particularly primary washouts need to be calculated according to

the draindown time (Twort 5th Edition)

2643 Break Pressure tanks

Static head is the difference in elevation from the source to any point on the ground profile

Static head must always be considered because excessive pressure in the pipe from the elevation

head can rapture the pipe or pipe connections Piping is rated by its ability to withstand an

internal pressure without breaking The ability is a function of the type of pipe material and

thickness of the wall pipe

Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure

that will rupture the pipe or cause failures at the joints

Page | 29

The function of a break pressure tank is to allow the flow to discharge into the atmosphere

thereby reducing its hydrostatic pressure to zero and establishing a new static level A general

rule of thumb is that the static head at any given point within the conduction line should not

exceed 100m of head There is no minimum required capacity for a break pressure tank as long

as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)

Page | 30

Chapter Three

30 METHODOLOGY

31 Introduction

Different data was needed for the design of a water supply system in Ongata Rongai Methods of

data collection were established beforehand to ensure the process was efficient Once the data

was collected it was analyzed to produce an outcome that satisfied the objective of the report

The data collected included

a) Population of the area

b) Land use

c) Topographical data

d) Existing water supply

e) Information on water consumption per capita in the area

In order to obtain this data various data collection methods were used as shown below

32 Data collection methods

Various methods were employed to collect data needed for the design of the system Both

primary and secondary data was needed The quantitative methods employed were to enable me

to obtain firsthand information needed for the project These include

a) Questionnaires

b) Interviews

c) Literature review

d) Government agencies

e) Direct observation

321 QuestionnairesQuestionnaires were prepared to aid with the collection of data The questionnaires were given to

the relevant parties In order to obtain an overview of water use in the area the questionnaire was

handed to the community for a brief description on how they use the water

Page | 31

With regards to the existing water supply it was necessary to involve Oloolaiser Water with the

use of questionnaires to obtain information on their existing system

322 InterviewsIn addition to questionnaires face to face interviews were also conducted The interviews were

done to collect data on the challenges facing the existing supply of water and the sources

available for people in the area These interviews were carried out with the members living in the

project area

Information on the proposed source was also required This particular interview was conducted

with the engineer who designed the dam itself The current population of the town and the

change of boundaries in the area over the past twenty years information was obtained from an

interview conducted with the technical manager at Oloolaiser Water and Sewerage Company

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area

323 Literature reviewDifferent reports were reviewed to get information in various areas This included the past

census reports to obtain the population of people in the area Information on land use and project

location description was also obtained from the NEMA Environmental Action plan for Kajiado

Land use data was necessary to establish where the pipeline would pass

324 Government AgenciesIn order to collect topographical data a map from the Survey of Kenya was obtained for the area

This map had information on the roads contours rivers all the natural and man-made features

which were necessary for the design of the system Information on sources of water supply in the

area was also obtained from the Oloolaiser water and sewerage company who are the water

service providers in the area

325 Direct ObservationDirect observation for information on settlement and land use was necessary because of the rate

at which the town is growing This was especially needed for the land adjacent to the road

because that was where the pipeline would pass and also to consider alternative routes for the

pipeline

Page | 32

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

2641 Pipes Appurtenances

Valves

Valves are used to control flow in a water system Most of the valves in a distribution system are

installed for isolation of sections of piping for maintenance and repair Control valves like

pressure reducing valves altitude valves pressure relief valves pressure sustaining valves and

pump control valves are designed to control pressures and throttle flows to prevent damage to the

system Air relief valves can vent trapped air from the system Check valves allow water to flow

only in one direction

Valves may be operated by hand or by actuator Actuators generally are electric and may be

operated locally or by remote control Where there is no local power supply portable power

packs may be used

Some examples of valves include

Gate Valve - Gate valves are the most common valves in a distribution system They are used for

isolation of equipment and piping They should never be used to throttle flow This will cause

damage to the valve face Open gate valves have the less friction loss than any other type of

valve Gate valves can have plug type disks or split gates Split gates are used in higher pressure

applications

Butterfly valves - Butterfly valves serve the same purpose as gate valves These valves usually

open and close with a quarter of a turn of the valve disc Larger valves will have a gear box on

the stem and will require a number of turns to open Butterfly valves are easier to open than gate

valves usually without the need for a bypass but have more friction loss when open They can

also be used for throttling flow without damaging the disc Caution should be used when filling a

line through a butterfly valve

Air Release Valve - Air release valves are used to allow air that may be trapped in the line to

escape The trapped air can create pressure and pumping problems milky-water complaints and

pressure spikes that resemble water hammer They are very useful in systems that are in hilly

country They should be located at the top of hills where the trapped air will collect

Page | 27

They are also used on booster pumps and wells to removed trapped air Combination air release

valves will also let air in when a vacuum occurs This is done to protect the piping They can also

be used to vent a line that is being drained All air-release valves should be equipped with

isolating valves for easy removal and repair of the air valves (Sacramento Water Distribution

System Manual 2000)

Section Valves - The valves should be placed in such a way that rationing of water can be done

by closing suitable parts of the supply for certain periods Whenever possible the section valves

should be placed in a joint valve chamber with air valves or washouts and upstream of these

valves In urban areas where fire-fighting is provided for there should be an isolating valve

downstream each fire hydrant (Water Design Manual 2005 Kenya)

Valve chambers

Large valves on trunk pipelines should be located in accessible chambers to facilitate

maintenance Smaller gate valves are usually buried Valve chambers should be at least 1000 x

1000mm internally There must not be UPVC-pipes within the chamber The cover should be

lockable The chamber should be drained through the floor or through a drain pipe

Hydrants

The fire insurance rates for residents on the system will be dependent in part on the proper

spacing and discharge capabilities of the fire hydrants in the system Hydrants should not be

more than 500-600 feet apart in residential districts The spacing requirements in industrial and

rural districts may vary They should be located at the end of every dead end line Hydrants

should be operated every 6 months and flow tested annually

Fire hydrants should never be placed on less than a 6 inch line if it is to be used for fire

protection In addition to provide fire protection hydrants can also be useful for flushing lines

venting lines as they are filled and pressure and flow testing Hydrants on smaller lines (4 inch

and down) will not supply enough water to fight a fire but may be used to flush dead end lines

Page | 28

Thrust Blocks

Wherever a bend elbow tee or dead-end exists in a pipeline having flexible joints a force is

exerted which tends to open the joints nearest the fittings The magnitude of this force varies

with the amount of bend the diameter of pipe and the pressure inside the pipe When

determining the resultant thrust for a given pipe it is advisable to use the maximum working

pressure anticipated in the pipe plus an allowance for surges or water hammer

Once the resultant thrust has been determined for a particular bend it becomes necessary to

provide a backing block of such size to resist the thrust The thrust must ultimately be borne by

the side of the pipe trench and the surrounding soil The purpose of the backing block is to

spread the thrust over an area sufficiently large that the undisturbed earth can support it

2642 Washouts

A washout is seldom used for scouring or washing out a main because its diameter is too small to

create sufficient flow velocity in the main to wash out debris Its principal use is for emptying a

main or for the removal of stagnant or dirty water

Primary washouts may be installed to drain to a watercourse the majority of the length between

section valves Secondary washouts of smaller diameter can then be used to empty undrained

subsections as required Sizes particularly primary washouts need to be calculated according to

the draindown time (Twort 5th Edition)

2643 Break Pressure tanks

Static head is the difference in elevation from the source to any point on the ground profile

Static head must always be considered because excessive pressure in the pipe from the elevation

head can rapture the pipe or pipe connections Piping is rated by its ability to withstand an

internal pressure without breaking The ability is a function of the type of pipe material and

thickness of the wall pipe

Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure

that will rupture the pipe or cause failures at the joints

Page | 29

The function of a break pressure tank is to allow the flow to discharge into the atmosphere

thereby reducing its hydrostatic pressure to zero and establishing a new static level A general

rule of thumb is that the static head at any given point within the conduction line should not

exceed 100m of head There is no minimum required capacity for a break pressure tank as long

as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)

Page | 30

Chapter Three

30 METHODOLOGY

31 Introduction

Different data was needed for the design of a water supply system in Ongata Rongai Methods of

data collection were established beforehand to ensure the process was efficient Once the data

was collected it was analyzed to produce an outcome that satisfied the objective of the report

The data collected included

a) Population of the area

b) Land use

c) Topographical data

d) Existing water supply

e) Information on water consumption per capita in the area

In order to obtain this data various data collection methods were used as shown below

32 Data collection methods

Various methods were employed to collect data needed for the design of the system Both

primary and secondary data was needed The quantitative methods employed were to enable me

to obtain firsthand information needed for the project These include

a) Questionnaires

b) Interviews

c) Literature review

d) Government agencies

e) Direct observation

321 QuestionnairesQuestionnaires were prepared to aid with the collection of data The questionnaires were given to

the relevant parties In order to obtain an overview of water use in the area the questionnaire was

handed to the community for a brief description on how they use the water

Page | 31

With regards to the existing water supply it was necessary to involve Oloolaiser Water with the

use of questionnaires to obtain information on their existing system

322 InterviewsIn addition to questionnaires face to face interviews were also conducted The interviews were

done to collect data on the challenges facing the existing supply of water and the sources

available for people in the area These interviews were carried out with the members living in the

project area

Information on the proposed source was also required This particular interview was conducted

with the engineer who designed the dam itself The current population of the town and the

change of boundaries in the area over the past twenty years information was obtained from an

interview conducted with the technical manager at Oloolaiser Water and Sewerage Company

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area

323 Literature reviewDifferent reports were reviewed to get information in various areas This included the past

census reports to obtain the population of people in the area Information on land use and project

location description was also obtained from the NEMA Environmental Action plan for Kajiado

Land use data was necessary to establish where the pipeline would pass

324 Government AgenciesIn order to collect topographical data a map from the Survey of Kenya was obtained for the area

This map had information on the roads contours rivers all the natural and man-made features

which were necessary for the design of the system Information on sources of water supply in the

area was also obtained from the Oloolaiser water and sewerage company who are the water

service providers in the area

325 Direct ObservationDirect observation for information on settlement and land use was necessary because of the rate

at which the town is growing This was especially needed for the land adjacent to the road

because that was where the pipeline would pass and also to consider alternative routes for the

pipeline

Page | 32

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

They are also used on booster pumps and wells to removed trapped air Combination air release

valves will also let air in when a vacuum occurs This is done to protect the piping They can also

be used to vent a line that is being drained All air-release valves should be equipped with

isolating valves for easy removal and repair of the air valves (Sacramento Water Distribution

System Manual 2000)

Section Valves - The valves should be placed in such a way that rationing of water can be done

by closing suitable parts of the supply for certain periods Whenever possible the section valves

should be placed in a joint valve chamber with air valves or washouts and upstream of these

valves In urban areas where fire-fighting is provided for there should be an isolating valve

downstream each fire hydrant (Water Design Manual 2005 Kenya)

Valve chambers

Large valves on trunk pipelines should be located in accessible chambers to facilitate

maintenance Smaller gate valves are usually buried Valve chambers should be at least 1000 x

1000mm internally There must not be UPVC-pipes within the chamber The cover should be

lockable The chamber should be drained through the floor or through a drain pipe

Hydrants

The fire insurance rates for residents on the system will be dependent in part on the proper

spacing and discharge capabilities of the fire hydrants in the system Hydrants should not be

more than 500-600 feet apart in residential districts The spacing requirements in industrial and

rural districts may vary They should be located at the end of every dead end line Hydrants

should be operated every 6 months and flow tested annually

Fire hydrants should never be placed on less than a 6 inch line if it is to be used for fire

protection In addition to provide fire protection hydrants can also be useful for flushing lines

venting lines as they are filled and pressure and flow testing Hydrants on smaller lines (4 inch

and down) will not supply enough water to fight a fire but may be used to flush dead end lines

Page | 28

Thrust Blocks

Wherever a bend elbow tee or dead-end exists in a pipeline having flexible joints a force is

exerted which tends to open the joints nearest the fittings The magnitude of this force varies

with the amount of bend the diameter of pipe and the pressure inside the pipe When

determining the resultant thrust for a given pipe it is advisable to use the maximum working

pressure anticipated in the pipe plus an allowance for surges or water hammer

Once the resultant thrust has been determined for a particular bend it becomes necessary to

provide a backing block of such size to resist the thrust The thrust must ultimately be borne by

the side of the pipe trench and the surrounding soil The purpose of the backing block is to

spread the thrust over an area sufficiently large that the undisturbed earth can support it

2642 Washouts

A washout is seldom used for scouring or washing out a main because its diameter is too small to

create sufficient flow velocity in the main to wash out debris Its principal use is for emptying a

main or for the removal of stagnant or dirty water

Primary washouts may be installed to drain to a watercourse the majority of the length between

section valves Secondary washouts of smaller diameter can then be used to empty undrained

subsections as required Sizes particularly primary washouts need to be calculated according to

the draindown time (Twort 5th Edition)

2643 Break Pressure tanks

Static head is the difference in elevation from the source to any point on the ground profile

Static head must always be considered because excessive pressure in the pipe from the elevation

head can rapture the pipe or pipe connections Piping is rated by its ability to withstand an

internal pressure without breaking The ability is a function of the type of pipe material and

thickness of the wall pipe

Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure

that will rupture the pipe or cause failures at the joints

Page | 29

The function of a break pressure tank is to allow the flow to discharge into the atmosphere

thereby reducing its hydrostatic pressure to zero and establishing a new static level A general

rule of thumb is that the static head at any given point within the conduction line should not

exceed 100m of head There is no minimum required capacity for a break pressure tank as long

as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)

Page | 30

Chapter Three

30 METHODOLOGY

31 Introduction

Different data was needed for the design of a water supply system in Ongata Rongai Methods of

data collection were established beforehand to ensure the process was efficient Once the data

was collected it was analyzed to produce an outcome that satisfied the objective of the report

The data collected included

a) Population of the area

b) Land use

c) Topographical data

d) Existing water supply

e) Information on water consumption per capita in the area

In order to obtain this data various data collection methods were used as shown below

32 Data collection methods

Various methods were employed to collect data needed for the design of the system Both

primary and secondary data was needed The quantitative methods employed were to enable me

to obtain firsthand information needed for the project These include

a) Questionnaires

b) Interviews

c) Literature review

d) Government agencies

e) Direct observation

321 QuestionnairesQuestionnaires were prepared to aid with the collection of data The questionnaires were given to

the relevant parties In order to obtain an overview of water use in the area the questionnaire was

handed to the community for a brief description on how they use the water

Page | 31

With regards to the existing water supply it was necessary to involve Oloolaiser Water with the

use of questionnaires to obtain information on their existing system

322 InterviewsIn addition to questionnaires face to face interviews were also conducted The interviews were

done to collect data on the challenges facing the existing supply of water and the sources

available for people in the area These interviews were carried out with the members living in the

project area

Information on the proposed source was also required This particular interview was conducted

with the engineer who designed the dam itself The current population of the town and the

change of boundaries in the area over the past twenty years information was obtained from an

interview conducted with the technical manager at Oloolaiser Water and Sewerage Company

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area

323 Literature reviewDifferent reports were reviewed to get information in various areas This included the past

census reports to obtain the population of people in the area Information on land use and project

location description was also obtained from the NEMA Environmental Action plan for Kajiado

Land use data was necessary to establish where the pipeline would pass

324 Government AgenciesIn order to collect topographical data a map from the Survey of Kenya was obtained for the area

This map had information on the roads contours rivers all the natural and man-made features

which were necessary for the design of the system Information on sources of water supply in the

area was also obtained from the Oloolaiser water and sewerage company who are the water

service providers in the area

325 Direct ObservationDirect observation for information on settlement and land use was necessary because of the rate

at which the town is growing This was especially needed for the land adjacent to the road

because that was where the pipeline would pass and also to consider alternative routes for the

pipeline

Page | 32

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Thrust Blocks

Wherever a bend elbow tee or dead-end exists in a pipeline having flexible joints a force is

exerted which tends to open the joints nearest the fittings The magnitude of this force varies

with the amount of bend the diameter of pipe and the pressure inside the pipe When

determining the resultant thrust for a given pipe it is advisable to use the maximum working

pressure anticipated in the pipe plus an allowance for surges or water hammer

Once the resultant thrust has been determined for a particular bend it becomes necessary to

provide a backing block of such size to resist the thrust The thrust must ultimately be borne by

the side of the pipe trench and the surrounding soil The purpose of the backing block is to

spread the thrust over an area sufficiently large that the undisturbed earth can support it

2642 Washouts

A washout is seldom used for scouring or washing out a main because its diameter is too small to

create sufficient flow velocity in the main to wash out debris Its principal use is for emptying a

main or for the removal of stagnant or dirty water

Primary washouts may be installed to drain to a watercourse the majority of the length between

section valves Secondary washouts of smaller diameter can then be used to empty undrained

subsections as required Sizes particularly primary washouts need to be calculated according to

the draindown time (Twort 5th Edition)

2643 Break Pressure tanks

Static head is the difference in elevation from the source to any point on the ground profile

Static head must always be considered because excessive pressure in the pipe from the elevation

head can rapture the pipe or pipe connections Piping is rated by its ability to withstand an

internal pressure without breaking The ability is a function of the type of pipe material and

thickness of the wall pipe

Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure

that will rupture the pipe or cause failures at the joints

Page | 29

The function of a break pressure tank is to allow the flow to discharge into the atmosphere

thereby reducing its hydrostatic pressure to zero and establishing a new static level A general

rule of thumb is that the static head at any given point within the conduction line should not

exceed 100m of head There is no minimum required capacity for a break pressure tank as long

as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)

Page | 30

Chapter Three

30 METHODOLOGY

31 Introduction

Different data was needed for the design of a water supply system in Ongata Rongai Methods of

data collection were established beforehand to ensure the process was efficient Once the data

was collected it was analyzed to produce an outcome that satisfied the objective of the report

The data collected included

a) Population of the area

b) Land use

c) Topographical data

d) Existing water supply

e) Information on water consumption per capita in the area

In order to obtain this data various data collection methods were used as shown below

32 Data collection methods

Various methods were employed to collect data needed for the design of the system Both

primary and secondary data was needed The quantitative methods employed were to enable me

to obtain firsthand information needed for the project These include

a) Questionnaires

b) Interviews

c) Literature review

d) Government agencies

e) Direct observation

321 QuestionnairesQuestionnaires were prepared to aid with the collection of data The questionnaires were given to

the relevant parties In order to obtain an overview of water use in the area the questionnaire was

handed to the community for a brief description on how they use the water

Page | 31

With regards to the existing water supply it was necessary to involve Oloolaiser Water with the

use of questionnaires to obtain information on their existing system

322 InterviewsIn addition to questionnaires face to face interviews were also conducted The interviews were

done to collect data on the challenges facing the existing supply of water and the sources

available for people in the area These interviews were carried out with the members living in the

project area

Information on the proposed source was also required This particular interview was conducted

with the engineer who designed the dam itself The current population of the town and the

change of boundaries in the area over the past twenty years information was obtained from an

interview conducted with the technical manager at Oloolaiser Water and Sewerage Company

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area

323 Literature reviewDifferent reports were reviewed to get information in various areas This included the past

census reports to obtain the population of people in the area Information on land use and project

location description was also obtained from the NEMA Environmental Action plan for Kajiado

Land use data was necessary to establish where the pipeline would pass

324 Government AgenciesIn order to collect topographical data a map from the Survey of Kenya was obtained for the area

This map had information on the roads contours rivers all the natural and man-made features

which were necessary for the design of the system Information on sources of water supply in the

area was also obtained from the Oloolaiser water and sewerage company who are the water

service providers in the area

325 Direct ObservationDirect observation for information on settlement and land use was necessary because of the rate

at which the town is growing This was especially needed for the land adjacent to the road

because that was where the pipeline would pass and also to consider alternative routes for the

pipeline

Page | 32

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

The function of a break pressure tank is to allow the flow to discharge into the atmosphere

thereby reducing its hydrostatic pressure to zero and establishing a new static level A general

rule of thumb is that the static head at any given point within the conduction line should not

exceed 100m of head There is no minimum required capacity for a break pressure tank as long

as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)

Page | 30

Chapter Three

30 METHODOLOGY

31 Introduction

Different data was needed for the design of a water supply system in Ongata Rongai Methods of

data collection were established beforehand to ensure the process was efficient Once the data

was collected it was analyzed to produce an outcome that satisfied the objective of the report

The data collected included

a) Population of the area

b) Land use

c) Topographical data

d) Existing water supply

e) Information on water consumption per capita in the area

In order to obtain this data various data collection methods were used as shown below

32 Data collection methods

Various methods were employed to collect data needed for the design of the system Both

primary and secondary data was needed The quantitative methods employed were to enable me

to obtain firsthand information needed for the project These include

a) Questionnaires

b) Interviews

c) Literature review

d) Government agencies

e) Direct observation

321 QuestionnairesQuestionnaires were prepared to aid with the collection of data The questionnaires were given to

the relevant parties In order to obtain an overview of water use in the area the questionnaire was

handed to the community for a brief description on how they use the water

Page | 31

With regards to the existing water supply it was necessary to involve Oloolaiser Water with the

use of questionnaires to obtain information on their existing system

322 InterviewsIn addition to questionnaires face to face interviews were also conducted The interviews were

done to collect data on the challenges facing the existing supply of water and the sources

available for people in the area These interviews were carried out with the members living in the

project area

Information on the proposed source was also required This particular interview was conducted

with the engineer who designed the dam itself The current population of the town and the

change of boundaries in the area over the past twenty years information was obtained from an

interview conducted with the technical manager at Oloolaiser Water and Sewerage Company

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area

323 Literature reviewDifferent reports were reviewed to get information in various areas This included the past

census reports to obtain the population of people in the area Information on land use and project

location description was also obtained from the NEMA Environmental Action plan for Kajiado

Land use data was necessary to establish where the pipeline would pass

324 Government AgenciesIn order to collect topographical data a map from the Survey of Kenya was obtained for the area

This map had information on the roads contours rivers all the natural and man-made features

which were necessary for the design of the system Information on sources of water supply in the

area was also obtained from the Oloolaiser water and sewerage company who are the water

service providers in the area

325 Direct ObservationDirect observation for information on settlement and land use was necessary because of the rate

at which the town is growing This was especially needed for the land adjacent to the road

because that was where the pipeline would pass and also to consider alternative routes for the

pipeline

Page | 32

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Chapter Three

30 METHODOLOGY

31 Introduction

Different data was needed for the design of a water supply system in Ongata Rongai Methods of

data collection were established beforehand to ensure the process was efficient Once the data

was collected it was analyzed to produce an outcome that satisfied the objective of the report

The data collected included

a) Population of the area

b) Land use

c) Topographical data

d) Existing water supply

e) Information on water consumption per capita in the area

In order to obtain this data various data collection methods were used as shown below

32 Data collection methods

Various methods were employed to collect data needed for the design of the system Both

primary and secondary data was needed The quantitative methods employed were to enable me

to obtain firsthand information needed for the project These include

a) Questionnaires

b) Interviews

c) Literature review

d) Government agencies

e) Direct observation

321 QuestionnairesQuestionnaires were prepared to aid with the collection of data The questionnaires were given to

the relevant parties In order to obtain an overview of water use in the area the questionnaire was

handed to the community for a brief description on how they use the water

Page | 31

With regards to the existing water supply it was necessary to involve Oloolaiser Water with the

use of questionnaires to obtain information on their existing system

322 InterviewsIn addition to questionnaires face to face interviews were also conducted The interviews were

done to collect data on the challenges facing the existing supply of water and the sources

available for people in the area These interviews were carried out with the members living in the

project area

Information on the proposed source was also required This particular interview was conducted

with the engineer who designed the dam itself The current population of the town and the

change of boundaries in the area over the past twenty years information was obtained from an

interview conducted with the technical manager at Oloolaiser Water and Sewerage Company

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area

323 Literature reviewDifferent reports were reviewed to get information in various areas This included the past

census reports to obtain the population of people in the area Information on land use and project

location description was also obtained from the NEMA Environmental Action plan for Kajiado

Land use data was necessary to establish where the pipeline would pass

324 Government AgenciesIn order to collect topographical data a map from the Survey of Kenya was obtained for the area

This map had information on the roads contours rivers all the natural and man-made features

which were necessary for the design of the system Information on sources of water supply in the

area was also obtained from the Oloolaiser water and sewerage company who are the water

service providers in the area

325 Direct ObservationDirect observation for information on settlement and land use was necessary because of the rate

at which the town is growing This was especially needed for the land adjacent to the road

because that was where the pipeline would pass and also to consider alternative routes for the

pipeline

Page | 32

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

With regards to the existing water supply it was necessary to involve Oloolaiser Water with the

use of questionnaires to obtain information on their existing system

322 InterviewsIn addition to questionnaires face to face interviews were also conducted The interviews were

done to collect data on the challenges facing the existing supply of water and the sources

available for people in the area These interviews were carried out with the members living in the

project area

Information on the proposed source was also required This particular interview was conducted

with the engineer who designed the dam itself The current population of the town and the

change of boundaries in the area over the past twenty years information was obtained from an

interview conducted with the technical manager at Oloolaiser Water and Sewerage Company

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area

323 Literature reviewDifferent reports were reviewed to get information in various areas This included the past

census reports to obtain the population of people in the area Information on land use and project

location description was also obtained from the NEMA Environmental Action plan for Kajiado

Land use data was necessary to establish where the pipeline would pass

324 Government AgenciesIn order to collect topographical data a map from the Survey of Kenya was obtained for the area

This map had information on the roads contours rivers all the natural and man-made features

which were necessary for the design of the system Information on sources of water supply in the

area was also obtained from the Oloolaiser water and sewerage company who are the water

service providers in the area

325 Direct ObservationDirect observation for information on settlement and land use was necessary because of the rate

at which the town is growing This was especially needed for the land adjacent to the road

because that was where the pipeline would pass and also to consider alternative routes for the

pipeline

Page | 32

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Some problems associated with water shortage could also be observed firsthand hand These

included polluted water sources and leaking pipes

33 Problems in collection of data

Anticipated problems in the collection of data included

1 Unavailable personnel qualified to fill my questionnaires at the government agencies

2 Resistance from the community in filling the questionnaire

3 Literature review not adequate

4 Unavailable data from the government agencies like water consumption of the area

In order to prevent these problems some steps were taken These were

a) It was necessary to make the questionnaire as short and precise as possible to ensure it

was not tedious for the person filling it

b) It was also necessary to book appointments with the relevant persons to be interviewed

in the government agencies to ensure they were available for the visit

c) Obtaining information on land use from the map was also a challenge This is due to the

fact that the area was mapped out almost 20 years ago and the area has developed since

then It was therefore necessary to use direct observation on the ground to map out some

of the sections in the area of study and also to make use of google earth

d) With regards to the literature review some estimates were made to obtain data that was

not available

34 Data analysis

The data collected from the various sources was then analyzed to produce the desired outcome

341 Population of the areaThe information on population of the area was used to determine water utilization in the area

This was used in conjunction with the data collected from the community on how they use their

water It was also compared with data from the Oloolaiser water and sewerage company so that

the gaps in the demand could be identified

Page | 33

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

332 Topographical data Topographical data was obtained from the map This was used to evaluate if water would flow

by gravity from the source to the project location or whether it would be necessary to pump to a

high altitude area in order to be distribute efficiently to the people or to choose an alternative

route where the water would flow by gravity

333 Proposed water supplyThe proposed water supply was mapped out on the map to show where the new pipeline would

pass exactly This was done to map out the area that will be serviced by the pipeline

334 ProfileA profile was created for the area to be serviced by the new pipeline after all the data collected in

the project area was analyzed This was the final outcome that lead to the design of the proposed

water supply network in the area This was done using a CAD program

Page | 34

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Chapter Four

40 RESULTS AND DISCUSSION

41 Questionnaire analysis

A brief questionnaire was handed to the community to get an overview of the water utilization in

the area and also the water shortages faced by the people in the area The project area was

divided into five zones where the sampling was done The areas chosen were based on the

different sources of water available in the different areas and the different living conditions

These were

1 Bangladesh

2 Kware

3 Nkoroi

4 Ongata Rongai Town

5 Fatima

Averages of 12 people were sampled in each of the areas above The total number of

questionnaires done was 60 in total The following results were obtained

411 Demographics

Gender distribution

The figure 41 below shows the gender distribution of people who were able to fill the

questionnaire when the data collection was done As seen below 75 of the people who were

available to answer the questionnaire were women This is because most of the households we

visited had only one person who was employed and in most cases it was the man For those that

had both of them employed we found the house help who assisted us with the information

Page | 35

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

male25

female75

Figure 41 Gender distribution

Type of family

Figure 42 below indicates that 90 of households in the area consist of nuclear families Only

10 of families comprise of extended families This can be attributed to the fact that the area is

highly populated and the cost of living has been increasing over the years due to the high number

of people who are moving to the area The area also has a large population of students because of

the three major universities namely Catholic University of East Africa Africa Nazarene

University and Multimedia University

Nuclear90

Extended10

Figure 42 Type of family

Page | 36

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Household size

As seen from figure 43 below 73 of households in the area have a maximum number of four

people There are three universities in the area as mentioned above and this could attribute to the

small household size Most of the houses in the area are rented by students who opt to live

outside school

1 to 473

5 to 727

Figure 43 Household size

Monthly income

The figure 44 below shows that the area consists of low middle and high income earning

people However 46 of people in the area earn between Shs 10000-50000 a month There are a

few slums in the area and they account for the 17 that earns below Shs 10000 Most of the

questionnaires were done in the slums because they are the people who are most affected by the

water shortages and quality problems existing in the area

17

47

17

20

lt1000010000-5000050001-100000gt100000

Figure 44 Monthly income

Page | 37

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Sources of water available in the area

The figure 45 below shows all the sources of water available in the area There are various

sources of water available in the area The sources include River Mbagathi and the various

boreholes in the area As shown below 46 of the area has water vendors Only 15 of the area

has access to River Mbagathi and the rest have piped water Most of the piped water in the area

comes from privately owned boreholes apart from a few households which get their water from

Oloolaiser water and Sewerage Company The company utilizes various sources one of them

being River Mbagathi

48

37

15

Piped

Water vendor

River

Figure 45 Sources of water available in the area

Utilized sources

The figure 46 below shows all the sources available in the area that are utilized by the

households The type of source dictates what the water will be used for whether irrigation

cooking washing drinking or livestock rearing The uses will be discussed in the sections that

follow depending on the source As seen below majority of the households utilize more than one

source of water because no source is deemed to be sufficient in terms of quality and quantity

Page | 38

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Piped only Water vendor only Piped and Water vendors

River and Water Vendors

0

2

4

6

8

10

12

14

16

18

20

Figure 46 Utilized sources

412 Water vendorsThe following results correspond to households that utilize water vendors as their main source of water

Time taken to fetch water

The figure 47 below shows the time taken to fetch water and return home Many water vendors

exist in the area because of the water shortage problem 36 of the people actually live close to

the water vendors For those who live quite a distance away they have it delivered to their

doorstep This accounts for 32 of the households that utilize water from the vendors

36

284

32

5 - 10 mins

11-30 mins

gt 30 mins

Delivered

Figure 47 Time taken to fetch water

Page | 39

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Frequency of buying water

Figure 48 below shows the frequency of buying water for the households that utilize water from

vendors 63 of the households buy their water once a day in the morning The water vendors

who sell water through donkeys normally have them delivered in the mornings It is therefore

convenient for the people to have them do so once a day in the morning For those who live close

to the vendors they buy their water more than once a day and this accounts for the 23

64

23

14

once a daymore than once a dayonce in three days

Figure 48 Frequency of buying water

Shortages

The figure 49 shows the frequency of shortages in the area 60 of people in the area

complained of water shortages while 40 did not experience it as a problem For those who

complained of shortages they have to buy water from the people who deliver it which makes it

more expensive than buying it from the water vendor

Yes60

No40

Figure 49 Shortages

Page | 40

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Price of water

As shown below on figure 410 there is a big variation in the water prices per jerrican the

highest price being Shs 20 and the lowest being Shs 4 This is brought about by many reasons

One of them is that the questionnaire was handed to people in different areas of the project area

The prices differ from zone to zone especially if one is buying from the vendors directly The

second reason is having water delivered to your doorstep by the donkeys will cost more The

price also varies for the different water vendors

Shs 4 Shs 5 Shs 6 Shs 10 Shs 15 Shs 200

2

4

6

8

10

12

Figure 410 Price of water per jerrican

413 Household water supply (Piped)The following results correspond to households that have piped as their main source of water

The source could either be from private boreholes or the sources utilized by the Oloolaiser water

and sewerage company

Frequency of water supply

50 of the people who have piped water supply indicated that the water comes for 24 hours a

day as shown in figure 411 below The project area is mostly supplied by boreholes and most

households with piped connections have water tanks which store water when it comes Most of

the water suppliers in the area pump the water once day for a few hours 28 indicated that the

water comes once in two days and the rest once a day

Page | 41

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

50

22

28

24 hour supplyonce a dayonce in two days

Figure 411 Frequency of water supply

Sufficiency of supply

61 of people in the area with piped water indicated that the frequency of the water supply was

sufficient for their needs as shown in figure 412 below Not all boreholes are reliable in terms of

the water supply This could be attributed to the fact the supply is determined by rainfall in the

area and if the household doesnrsquot have enough storage for such situations they will experience

shortages

Yes61

No39

Figure 412 Sufficiency of supply

Page | 42

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

414 RiverOnly a small percentage of the area utilizes water from the river directly They live in an area

called Bangladesh just before you get to the town itself They fetch water for their plants and also

use the water to wash clothes

The river water is not suitable for human consumption because it is polluted by sewerage from

Mbagathi view Secondary School and Multimedia University We know the river is polluted

somewhere downstream because Oloolaiser uses it as one of their sources upstream The figure

413 below shows a part of River Mbagathi downstream

Figure 413 River Mbagathi

415 Common questions

Adequacy of main source

From figure 414 it is clear that 68 of the people responded that the quantity received from the

main source was adequate This response mainly came from households with a piped connection

and those who have water delivered to their doorsteps by the water vendors

Page | 43

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Yes68

No32

Figure 414 Adequacy of main source

Availability of water throughout the year

60 of the households said they experience water shortages as shown in figure 415 below The

area is semi-arid and since most of the household get their supply from boreholes therersquos

normally a shortage when therersquos prolonged drought

This is because the water level goes down in the boreholes

Yes60

No40

Figure 415 Availability of water throughout the year

Page | 44

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Taste

92 of the water in the area is hard water and it generally has a salty taste as shown in figure

416 below Only a few households get soft water

Hard92

Soft8

Figure 416 Taste

Turbidity

As shown in figure 417 below 80 most households have clear water Only 11 of the

households which we interviewed complained of cloudy or dirty water

89

11

ClearCloudy

Figure 417 Turbidity

Page | 45

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Paying for water

82 of population in the area pays for water while 18 doesnrsquot pay as shown in figure 418

below Those who donrsquot pay for it have it included in the rent The landlord is therefore the one

who handles water payment This is mostly so when the owner of the houses has a borehole to

supply the tenants

Yes82

No 18

Figure 418 Paying for water

Monthly water payment

As seen in figure 419 below 82 of households spend Shs 2000 and below on water bills It

mostly depends on the usage and the per unit rate of the different suppliers The lesser amounts

are for those who get their water from the Oloolaiser water and sewerage company

41

41

18

lt Shs 1000Shs 1001 - 2000gt Shs 2000

Figure 419 Monthly water payments

Page | 46

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Willingness to pay more in order to obtain a better quality of water

35 of the people will not be willing to spend more in order to obtain a better quality of water as

shown in figure 420 below This is mainly because of two reasons One of them is that they

cannot afford to spend any more money to get water They can barely afford the current supply

they have The second reason is that some of the households are comfortable with their current

supply

Yes65

No35

Figure 420 Willingness to spend more on better quality

Water utilization

86 of water in the area is mostly used for domestic purposes as shown in figure 421 below

This is especially so in the town itself where people donrsquot have land to do either farming or

livestock rearing As you move away from the town there are a few households which practice

irrigation on their farms while others keep livestock

86

2

12

DomesticLivestock Irrigation

Figure 421 Water utilization

Page | 47

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Rainwater harvesting

From the figure 422 below it is seen that rainwater harvesting is practiced by 60 of people in

the area but it is not done in large scale Most people in the area fetch between 40 to 200 litres

when it rains sufficiently They use the water to either wash clothes or other domestic purposes

Yes40

No60

Figure 422 Rainwater Harvesting

Drinking water

As shown in figure 423 below 70 of people in the area buy their drinking water They cannot

stand the taste of hard water This in turn incurs more expense to a commodity which is already

expensive The few people who still take hard water are either used to it or cannot afford to be

buying drinking water

Yes 70

No30

Figure 423 Drinking water

Page | 48

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

416 Oloolaiser interview and questionnaire response

Water Source and certification of entire system

Sources of water in Ongata Rongai are mainly surface water and boreholes

The water system capacity does not meet or exceed the daily demand requirements for the area

The current service coverage is at 60 The deficit will be reduced through the development of

service distribution networks serving water from the newly completed Kiserian dam at a capacity

of 10205m3 day

The source is rain fed since there is no consistency in the rain seasons the source may not meet

the demand for the next 5years There is need for additional source development thereafter

Existing system

The areas that the system supplies

1 Nkaimurunya Location

2 Ongata Rongai Location

3 Olekasasi Location

They cover only 75 of the service area The current flow from all the sources is 7000m3day

The independent sources include

1 Mbagathi River Intake

2 Kiserian Dam

3 3 boreholes

42 Population data

421 Human PopulationThe population of the area was got from the previous census reports The boundaries of the area

have changed with every census The last three census reports were used to calculate the

population growth rate of the area It was observed that in 1989 Nkaimurunya was a sub-

location in Ongata Rongai In the next census which was in 1999 Nkaimurunya was a location

on its own with Olkeri as one of its sub-location Lemelepo was also a sub-location in Ongata

Page | 49

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Rongai In the last census which was in 2009 Olkeri and Lemelepo became locations on their

own Therefore over the past twenty years Ongata Rongai has produced three locations The

population of the area from the previous census reports is as follows

Table 41 Human population data

Year Population1989 322891999 608442009 100084

The population growth rate in the area was calculated using the data from the previous census

reports as follows The following formula was used

P=PO (1+r )n

R = (P P0)1n - 1

WhereP ndash Projected population after n yearsP0 ndash Population during the reference yearr ndash Population growth factorn ndash Projection period

Location 1989 1999 2009Growth rate in 1989-1999 1999-2009

Ongata Rongai 32289 60844 10084 65 51

Average growth rate = 65+51

2=iquest 58

The prediction of future population is essential in connection with the planning of water

supply system The population projection was based on the present initial future and

ultimate periods as follows

Present Year 2014Initial Year 2015Future Year 2025Ultimate Year 2035

The formula above was used

Page | 50

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Table 42 Population projection for the area

Current Population Projections

Location

Popu

latio

n

Growth Rate as

a

Current 2014

Initial 2015

Future 2025

Ultimate 2035

Ongata Rongai 100084 58 100084 105889 186083 327012TOTALS 100084 100084 105889 186083 327012

422 Service infrastructure population

Table 43 ECD schools population data

ECD all ages Boys Girls Total

Public schools 496 408 904

Private schools 756 750 1506

TOTALS 1252 1158 2410

Table 44 Public primary schools population data

Class Boys Girls Total

Standard 1 422 426 848

Standard 2 446 426 872

Standard 3 557 577 1134

Standard 4 643 707 1350

Standard 5 703 716 1419

Standard 6 719 753 1472

Standard 7 716 785 1501

Standard 8 633 654 1287

TOTALS 4839 5044 9883

Page | 51

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Table 45 Private primary schools population data

Class Boys Girls Total

Standard 1 347 352 699

Standard 2 375 328 703

Standard 3 360 330 690

Standard 4 343 302 649

Standard 5 301 267 568

Standard 6 252 257 509

Standard 7 211 246 457

Standard 8 212 223 435

TOTALS 2405 2305 4710

Total number of teachers from primary section = 465 teachers

Table 46 Secondary schools population data

School Pupils Teachers

Ncooro Academy 212 10

Nakeel boys Secondary School 475 25

Nkaimurunya mixed Secondary School 344 19

Nkoroi day Mixed Secondary School 135 7

Olekasasi Secondary School 330 15

Bishop Mazzoldi Secondary School 284 13

Mbagathi View Secondary School 367 22

TOTALS 2147 111

Schools Projections

Page | 52

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Table 47 Schools population projection for the area

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 2410 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

Health centresOngata Rongai mainly has health centres and a few hospitals These are

Table 48 Health centres data

423 Livestock PopulationThe present livestock population was estimated based on the livestock census available from the

District Livestock officer

Table 49 Livestock population data

Page | 53

Health centre Bed Capacity

Beacon of hope Clinic 0

Afya yetu Medical Centre 0

Kkit Maternity 7

Nairobi Women Hospital 77

Vicodec Medical Clinic 0

PCEA Smyrna 4

Mariakani Cottage Hospital 10

Kenyatta National Hospital 26

Aga Khan Hospital 0

Elim Dental Clinic 0

Faith Health Clinic 0

Garlands Medical Centre 0

Gertrudes Childrenrsquos Centre 0

Meridian Medical Centre 0

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Unit Number

Dairy cattle 14371

Beef cattle 7039

Sheep 10163

Goats 9535

Chicken 10450

Pigs 825

Rabbits 1584

Donkeys 265

An assumption is made that the rate at which livestock die is the same as the rate at which they

reproduce Therefore the number of livestock in the area remains constant and no growth rate

factor is used For the purpose of estimating the water demand for livestock the following

conversion factors apply as indicated in the Water Design manual 2005

1 Grade cow equivalent to 1 Livestock Unit (LU)

3 Indigenous cows to 1 Livestock Unit (LU)

15 Sheep or goats to 1 Livestock Unit (LU)

5 Donkeys to 1 Livestock Unit (LU)

2 Camels to 1 Livestock Unit (LU)

Since the manual gave no conversion factors for rabbits and chicken the following

approximations were used

30 Chickens to 1 Livestock Unit (LU)

40 Rabbits to 1 Livestock Unit (LU)

The above conversion yielded the following livestock units

Table 410 Livestock conversion data

Unit Number Livestock Unit

Dairy cattle 14371 14371

Beef cattle 7039 2346

Page | 54

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Sheep and goats 19698 1313

Chicken 10450 348

Pigs 825 42

Rabbits 1584 40

Donkeys 265 53

TOTAL 18153

43 Water Demand

431 Population demandAll urban areas are planned as per the Physical planning handbook published by the Ministry of

Lands Ongata Rongai was never planned therefore reasonable assumptions had to be made in

classifying the land uses in order to get the water demand of the area Ongata Rongai is an urban

area therefore no consideration was made for the surrounding rural areas

The assumptions made were the urban areas could be divided into the following as per the water

design manual

1 High Class Housing this constitutes roughly 15 of the population

2 Medium Class Housing this constitutes roughly 55 of the population

3 Low Class Housing this constitutes roughly 30 of the population

In order to cater for the service type the table below from the water design manual was used

Table 411 Service type

IC NC

Initial Future Ultimate Initial Future Ultimate

Urban Areas

Page | 55

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

High and Medium Class 100 100 100 0 0 0HousingLow class Housing 10 30 50 90 70 50Rural AreasHigh potential 20 40 80 80 60 20Medium potential 10 20 40 90 80 60Low potential 5 10 20 95 90 80

Using the above figures the following table can be generated

Table 412 Human population data according to service type

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 49919 87725 154163 0 0 0

Low class 4236 22330 65402 38120 52103 65403

Table 413 Water consumption rates

Consumer Unit

RURAL AREAS URBAN AREAS

High Potential

Medium Potential

Low Potential

High Class Housing

Medium Class Housing

Low Class Housing

People with individual connections

lheadday

60 50 40 250 150 75

People without

lheadday

20 15 10 - - 20

Page | 56

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

connectionsLivestock units

lheadday

50 -

Boarding schools

lheadday

50

Day schoolsWith WCWithout WC

lheadday

255

HospitalsRegionalDistrictOther

lbedday

400200100

Dispensary and Health Centre

lday 5000

HotelsHigh ClassMedium ClassLow Class

lbedday

600

30050

Administrative Offices

lheadday

25

Bars lday 500Shops lday 100Unspecified industry

lhaday 20000

Coffee pulping factories

lkg coffee

25 when re ndash circulation of water is used)

Page | 57

+ 20 l per outpatient and day

(Minimum 5000 lday)

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

As an approximation since the values given in the manual were too high the following was used

for the human population

Table 414 Water demand used in lpday

Type of housing Demand in lpersonday

High class 100

Medium class 70

Low class 50

For the non-individual connections 20 litres was allocated per person per day for each

household This was an over-estimate because results from the questionnaire indicated that they

use less than that

Table 415 Water demand in m3day human population

Type of Housing

Individual Connections(IC) Non-Individual Connections(NIC)

Initial 2015

Future 2025

Ultimate 2035

Initial 2015

Future 2025

Ultimate 2035

High class 13614 23925 42044 0 0 0

Medium Class 349433 614075 1079141 0 0 0

Low class 2118 11165 32701 7624 104206 130806

TOTAL 5068 9650 18266 762 1042 1308

432 Service infrastructure demand

Most schools in the area are day schools including the secondary schools Most of the schools

donrsquot have a water closet Therefore a reasonable assumption of 10 lhead can be allocated to the

school population

Page | 58

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Table 416 Water demand in m3day institution population

Institution Current 2014 Initial 2015 Future 2025 Ultimate 2035

ECD schools 241 2550 4481 7875

Primary schools 15058 15931 27996 49199

Secondary schools 2258 2389 4198 7378

TOTALS 197 209 367 645

Health centres

Table 417 Water demand in m3day health centres

Health centre Bed Capacity Demand (m3)

Beacon of hope Clinic 0 5

Afya yetu Medical Centre 0 5

Kkit Maternity 7 5

Nairobi Women Hospital 77 92

Vicodec Medical Clinic 0 5

PCEA Smyrna 4 5

Mariakani Cottage Hospital 10 5

Kenyatta National Hospital 26 5

Aga Khan Hospital 0 5

Elim Dental Clinic 0 5

Faith Health Clinic 0 5

Garlands Medical Centre 0 5

Gertrudes Childrenrsquos Centre 0 5

Meridian Medical Centre 0 5

TOTAL 742

433 Livestock demandAccording to the design manual 50lhead is allocated to a livestock unit

Page | 59

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Table 418 Water demand in m3day livestock population

Unit Number Livestock Unit Demand m3

Dairy cattle 14371 14371 71855

Beef cattle 7039 2346 1173

Sheep and goats 19698 1313 6565

Chicken 10450 348 174

Pigs 825 42 21

Rabbits 1584 40 2

Donkeys 265 53 265

TOTALS 18153 92565

Business was assumed to account for 15 of the human consumption

Table 419 Summary of water demand in m3 day

UseConsumption rate (m3day)

Human 19574

School 645

Livestock 926

Dispensaries 74

Business (15) 318

TOTALS 21537

Page | 60

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

44 Pipe Network Design

The realistic and most economical route for the main pipeline was determined This route was

determined on the basis of flow by gravity Initially the main pipeline was to pass along the road

but after the road profile was determined it was observed that the ground was undulating with

areas which had higher levels than the static level at the source After much consideration

another path was determined that wasnrsquot along the road which allowed the flow of water by

gravity hence no pumping was necessary

To determine the pipe diameters the Darcy-Weisbachrsquos formula was employed as illustrated

below The total length of the pipeline was 1547Km therefore there was no consideration of

bends in the calculation of head loss in the pipe The only loss considered was the friction head

loss through the pipe

441 Design of main trunk line The total length of the pipeline was 1547 km The difference in levels between the first and last

point on the main trunk line was given by

Static water level = 1800m

Level at 1547km = - 1717m

83m

Total head loss along the full length 83m

Darcy-Weisbachrsquos formula

hL=f lD

v2

2 g

Where

hL = Head loss in m

f = Friction factor from Moody chart

l = Length of pipe in m

D = Diameter of pipe

V = Velocity of flow ms

Page | 61

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

g = acceleration in m2s

In order to obtain the diameter the equation above was modified as shown below

Since QiquestAV and A=π D2

4

hL=16 fLQ2

2 D5 π2 g

The flow from the source is 7500m3day which translates to 00868m3s

Inputting the following values Q = 00868m3s L= 15470m g = 981m2s and hL = 83m yields the

following

D5 = 0116f

In order to use the Moody chart we need to obtain a value for Reynoldrsquos number given by

real=DVρμ

Where

D = Diameter of pipe

V = Velocity of flow

ρ=iquestDensity of water 1000kgm3

μ=iquestDynamic Viscosity of water at 200C which is 0001002

Replacing V with QA gives real=4 QVρ

π D2 μ

Inputting the values yields real=110517 times103

D

As a first approximation a diameter of 300mm was assumed

The pipe material selected for this design was steel which is locally manufactured and available

Page | 62

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 300mm is 000014

The Reynolds number will be given by110517times103

03=368390 times105

From the chart f will be 00152

D5 = 0116 times 00152 =176 times10minus3

D = 281mm

The new Reynolds number 110517times103

0281=394 times 105

From the chart f will be 0015

A 300mm diameter pipe will therefore be sufficient

The head loss per kilometer was then calculated

hL=16 fLQ2

2 D5 π2 g

16 times0015 times1000 times008682

2times 035times π 2times 981=384 m

After calculating the head loss through the whole length and obtaining the hydraulic gradient line

it was observed that the line went below the profile of the main trunk line It was therefore

necessary to increase the pipe diameter to 350mm to reduce the head loss along the pipe

New diameter 350mm

From the Moody chart εD for a commercial steel pipe for a pipe diameter of 350mm is 000013

The Reynolds number will be given by110517times103

035=315762 times105

Page | 63

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

From the chart f will be 0016

New head loss per kilometer

16 times0016 times1000 times 008682

2times 0355times π 2times 981=1896 m

This was repeated for the distribution lines to yield the following

Table 420 Pipeline details

Pipeline Length(km) Design flow(Ls) Diameter(mm) Head loss per km(m)

Main trunk line 1547 868 350 1896

A - B 11 35 100 233

C - D 13 58 100 578

E - F 105 46 100 385

A cover of 1m was taken for the pipeline and the profiles of the pipes were then plotted

Page | 64

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Chapter Five

50 CONCLUSION AND RECOMMENDATION

From the above results the following two main deductions could be made

51 Considerations in design

A lot of considerations need to be made when it comes to the design of water supply systems

One of the major aspects to be considered is the population growth of the area This is especially

important in the design of water supply systems because they are designed for the next 20 years

After calculating the demand of the area it was observed that the flow from the dam could not

sustain the demand for the next 20 years This therefore brings the need to look for other sources

of water to meet the demand

The dam construction began in 1992 but it stalled because of lack of funding This is another

problem faced by the relevant bodies in implementing the different projects This problem is then

propagated to the design and implementation of the project This is because when coming up

with the design and construction begins it is meant to cater for the demand of the area for the

next twenty years However when the project is finally completed almost twenty years down the

line the demand will have changed by that time especially in a fast growing town like Ongata

Rongai

52 Community involvement

Another important aspect in community projects is community participation In this particular

project it was done through the use of questionnaires and interviews This helps the designer to

address the needs of the community at hand This is where most engineers go wrong and this is

why it has become mandatory for every project to be preceded by an environmental and social

impact assessment The interviews provided an overview of water usage and the different

problems associated with water shortage and water quality in the area It is therefore an

important parameter when it comes to the design and implementation of the projects

Page | 65

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Unfortunately not much attention is paid to it and therefore different problems arise from it One

of the problems could be lack money on the consumer side to be able to buy the water especially

in low income areas where they barely have money for food

53 Recommendations

Consider other sources of water which includes tapping rainwater when it rains heavily

considering most of the rivers flood and become impassable when it rains heavily This

will include construction of check dams upstream of the rivers

Enforce laws which govern pollution of the natural sources of water like river Mbagathi

which is polluted by waste from institutions in the area The river could serve as an

alternative source of water for the people who live adjacent to it but instead it is only fit

for irrigation because of its bad quality

Another alternative would be to design and come up with a sewerage system for the area

This would reduce the amount of pollution that goes into the rivers in the area

For the low income areas it would be advantageous for the relevant bodies to consider

subsidized prices for water As revealed from the interviews with the people they

expressed their concern that water has become one of the most expensive commodities

yet they cannot do without it

Alternative methods of treating hard water to make it suitable for drinking should be

considered Most of the people in the area as revealed from the questionnaire analysis

buy drinking water

Page | 66

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

60 REFERENCES1 California State University Sacramento (2000) Water Distribution System O amp M Manual 4th

Edition

2 Faust R W (2007) The Hydraulic Principles of Water Supply Systems PDH Center

3 Government of Kenya (2009) Kajiado District Environment Action Plan 2009-2013 NEMA

4 Hofkes EH Huisman L amp International Reference Centre for Community Water Supply and Sanitation (1983) Small Community Water Supplies Technology of Small Water Supply Systems in Developing Countries International Reference Centre for Community Water Supply and Sanitation

5 James R Mihelcic et al (2009) Field Guide to Environmental Engineering for Development Workers Water Sanitation and Indoor air American Society of Civil Engineers

6 Ministry of Water and Irrigation (2005) Water Design Manual Kenya

7 M Sundaravadivel S Vigneswaran et al (2007) Rural Water Supply System - Small and Rural Community Water Supply in Vigneswaran SV (ed) Wastewater Recycle Reuse and Reclamation UK pp 1-23

8 P N de Leeuw et al (1991) Chapter 2 Introduction to the Kenyan rangelands and Kajiado district httpwwwfaoorgwairdocsILRIx5552Ex5552e04htm

9 Susan S Hutson et al (2004) Estimated use of water in the United States in 2000 US Geological Survey httppubsusgsgovcirc2004circ1268 released March 2004

10 Twort A amp Hoather R a (1994) Water supply 2nd ed London Edward Arnold Publishers

11 World Bank (2012) Rural Water Supply Volume one design manual Water Partnership Program Philippines

Page | 67

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

APPENDICES

Page | 68

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Appendix 1 HGL calculations

11 Main trunk line

Chainage (km)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1800 0 350 0 1800 1800 18001 1791 1 350 1896 1798104 1798062716 18002 1778 1 350 1896 1796208 1796166716 18003 1768 1 350 1896 1794312 1794270716 18004 1778 1 350 1896 1792416 1792374716 18005 1776 1 350 1896 179052 1790478716 18006 1769 1 350 1896 1788624 1788582716 18007 1766 1 350 1896 1786728 1786686716 18008 1779 1 350 1896 1784832 1784790716 18009 1775 1 350 1896 1782936 1782894716 180010 1762 1 350 1896 178104 1780998716 180011 1767 1 350 1896 1779144 1779102716 180012 1758 1 350 1896 1777248 1777206716 180013 1742 1 350 1896 1775352 1775310716 180014 1738 1 350 1896 1773456 1773414716 180015 1704 1 350 1896 177156 1771518716 18001547 1717 047 350 0891 1770669 1770627716 1800

12 Pipeline A ndash B

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1742 0 100 0 1742 1742 1742100 1741 100 100 0233 1741767 1741756679 1742200 1740 100 100 0233 1741534 1741523679 1742300 1740 100 100 0233 1741301 1741290679 1742400 1739 100 100 0233 1741068 1741057679 1742500 1735 100 100 0233 1740835 1740824679 1742600 1731 100 100 0233 1740602 1740591679 1742700 1729 100 100 0233 1740369 1740358679 1742800 1735 100 100 0233 1740136 1740125679 1742900 1736 100 100 0233 1739903 1739892679 17421000 1735 100 100 0233 173967 1739659679 17421100 1733 100 100 0233 1739437 1739426679 1742

Page | 69

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

13 Pipeline C ndash D

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1743 0 100 0 1743 1743 1743100 1742 100 100 0578 1742422 174239409 1743200 1741 100 100 0578 1741844 174181609 1743300 1742 100 100 0578 1741266 174123809 1743400 1739 100 100 0578 1740688 174066009 1743500 1739 100 100 0578 174011 174008209 1743600 1738 100 100 0578 1739532 173950409 1743700 1737 100 100 0578 1738954 173892609 1743800 1734 100 100 0578 1738376 173834809 1743900 1732 100 100 0578 1737798 173777009 17431000 1729 100 100 0578 173722 173719209 17431100 1730 100 100 0578 1736642 173661409 17431200 1728 100 100 0578 1736064 173603609 17431300 1730 100 100 0578 1735486 173545809 1743

14 Pipeline E ndash F

Chainage (m)

Ground level (m)

Distance (m)

Pipe Diameter (mm)

Head loss (m)

TEL (m) HGL(m) Static head (m)

0 1735 0 100 0 1735 1735 1735100 1733 100 100 0385 1734615 173457186 1735200 1732 100 100 0385 173423 173418686 1735300 1729 100 100 0385 1733845 173380186 1735400 1728 100 100 0385 173346 173341686 1735500 1729 100 100 0385 1733075 173303186 1735600 1726 100 100 0385 173269 173264686 1735700 1721 100 100 0385 1732305 173226186 1735800 1720 100 100 0385 173192 173187686 1735900 1718 100 100 0385 1731535 173149186 17351000 1710 100 100 0385 173115 173110686 17351050 1706 50 100 0193 1730957 173091386 1735

Page | 70

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Appendix 2 Moody chart

Page | 71

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Appendix 3 Standard pipes

Table 164 Locally manufactured steel pipes (Water design manual 2005)

Page | 72

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Appendix 4 Questionnaire sample

QUESTIONNAIRE FOR AID OF DESIGN FOR WATER SUPPLY SYSTEM

This questionnaire is meant to help me with the design of water supply system in Ongata Rongai

All information disclosed here will remain confidential

Section 1 DEMOGRAPHIC QUESTIONS

1 What is your name __________________________________________________________________

2 Gender of respondent _________________________________________________________________

3 What is your age ____________________________________________________________________

4 Location ___________________________________________________________________________

5 Type of family 1048710 Nuclear

1048710 JointExtended6 Household size _________________________________________________________people

7 How many members in the household are employed ____________________________people

8 What is the monthly household income

1048710 lt Ksh 10000 1048710 Ksh 10000 - 500001048710 Ksh 50001 - 1000001048710 gt Ksh 100000

Section 2 WATER SUPPLY

9 Which of the following sources of water are available in your area

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Household water supply (piped)1048710 River1048710 Other (Please specify) ________________________________

10 Which of the following sources of water does your household use

1048710 Bore well hand pump (skip to question 11)1048710 Public tap (water vendors) (skip to question 16)1048710 Household water supply (piped) (skip to question 21)1048710 River (skip to question 25)1048710 Other (Please specify) ________________________________

Page | 73

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

Bore wellhand pump

11 How far is the bore well hand pump that you use _______________________________Kilometres

12 How long does it take to fetch water and return home _____________________________Minutes

13 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

14 Has the hand pump broken down in the past one year 1048710 Yes 1048710 No

15 How frequent has the hand pump broken down during the past one year

1048710 Once a week1048710 Once a fortnight1048710 Once a quarter1048710 Once in 6 months1048710 Once a year

Public tap (Water Vendors)

16 How far are the water vendors from your household ______________________kilometres

17 How long does it take to buy water and return home _____________________ Minutes

18 How frequent do you buy water from the vendors

1048710 More than once a day1048710 Once a day1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

19 Do you normally experience shortages 1048710 Yes 1048710 No

If yes how often ____________________________________________________________

20 How much do you buy the water per jerrican ________________________Ksh

Household water supply (piped)

21 What is the frequency of water supply

1048710 24 hour supply1048710 More than once a day1048710 Once a day

Page | 74

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

1048710 Once in two days1048710 Once in three days1048710 Other (Please specify) _________________________________________________________

22 Is this frequency sufficient for your needs 1048710 Yes 1048710 No

23 How often would you like to get water

1048710 More than once a day1048710 Once a day1048710 Other (Please specify) _________________________________________________________

24 On the days you get water how many hours do you get water for _________________hours

River

25 How far is the river from your household _________________________kilometres

26 How long does it take to fetch water and return home _____________________________Minutes

27 Who fetches water most of the time

1048710 Adult male 1048710 Adult female1048710 Male child1048710 Female child

28 Do you treat the water after you have fetched it from the river 1048710 Yes 1048710 No

If yes how (Please explain)___________________________________________________

29 What type of river is it 1048710 Seasonal 1048710 Permanent

30 Do you experience shortages 1048710 Yes 1048710 No

31 What other source of water does your household use in case of shortages

1048710 Bore well hand pump1048710 Public tap (water vendors)1048710 Other (Please specify) ________________________________

COMMON QUESTIONS

32 Is the quantity you receive from your main source of water adequate 1048710 Yes 1048710 No

33 Is water available throughout the year 1048710 Yes 1048710 No

Page | 75

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample

34 Which month(s) do you find scarcity Please specify ________________________________

35 Generally does the water have a smell 1048710 No smell 1048710 Foul smell

36 Generally does the water have a taste 1048710 Yes 1048710 No

37 Generally what does the water look like 1048710 Clear 1048710 Cloudydirty

38 Do you pay for water 1048710 Yes 1048710 No

39 How much do you pay for water per month __________________________________Ksh

40 Would you be willing to spend more money in order to obtain a better quality of water for drinking and other purposes 1048710 Yes 1048710 No

If no why (Please explain)________________________________________________________

41 What are the various areas in which you utilize your water List as appropriate1048710 Irrigation1048710 Livestock1048710 Domestic purposes1048710 Other (Please specify) _________________________________________________________

42 Do you practice rainwater harvesting methods in your household 1048710 Yes 1048710 No

43 If yes how much water are you able to harvest during the rainy season

________________________________________________________________________Litres

44 Do you buy drinking water 1048710 Yes 1048710 No

Page | 76

• Abstract
• Dedication
• Acknowledgements
• List of figures
• List of tables
• Chapter One
• 10 Introduction
• • 11 General
  • 12 Problem Statement
  • 13 The objective and scope of study
  • • Chapter Two
    • 20 LITERATURE REVIEW
    • • 21 Water Occurrence and Hydrology
      • 22 Description of area
      • • 221 Location
        • 222 Climate
        • 223 Topography and Geology
        • 224 Socio-economic Infrastructure
        • • 2241 Administration
          • 2242 Education
          • 2243 Health Facilities
          • 2244 Transport
          • 2245 Commerce and Industry
          • 2246 Agriculture
          • • 23 Water sources
            • • 231 Ground water sources
              • 232 Surface water sources
              • • 24 Water Demand
                • 25 Population projections
                • 26 Water distribution
                • • 261 Water Demand Variation
                  • 262 Balancing storage
                  • 263 Distribution system design
                  • 264 Pipes
                  • • 2641 Pipes Appurtenances
                    • 2642 Washouts
                    • 2643 Break Pressure tanks
                    • • Break pressure tanks are strategically placed along the pipeline to eliminate excessive pressure that will rupture the pipe or cause failures at the joints
                      • The function of a break pressure tank is to allow the flow to discharge into the atmosphere thereby reducing its hydrostatic pressure to zero and establishing a new static level A general rule of thumb is that the static head at any given point within the conduction line should not exceed 100m of head There is no minimum required capacity for a break pressure tank as long as the water is able to drain from it as quickly as it is discharged ( James R Mihelcic et al 2009)
                      • Chapter Three
                      • 30 METHODOLOGY
                      • • 31 Introduction
                        • 32 Data collection methods
                        • • 321 Questionnaires
                          • 322 Interviews
                          • 323 Literature review
                          • 324 Government Agencies
                          • 325 Direct Observation
                          • • 33 Problems in collection of data
                            • 34 Data analysis
                            • • 341 Population of the area
                              • 332 Topographical data
                              • 333 Proposed water supply
                              • 334 Profile
                              • • Chapter Four
                                • 40 RESULTS AND DISCUSSION
                                • • 41 Questionnaire analysis
                                  • • 411 Demographics
                                    • 412 Water vendors
                                    • 413 Household water supply (Piped)
                                    • 414 River
                                    • 416 Oloolaiser interview and questionnaire response
                                    • • 42 Population data
                                      • • 421 Human Population
                                        • 422 Service infrastructure population
                                        • 423 Livestock Population
                                        • • 43 Water Demand
                                          • • 431 Population demand
                                            • 432 Service infrastructure demand
                                            • 433 Livestock demand
                                            • • 44 Pipe Network Design
                                              • • 441 Design of main trunk line
                                                • • Chapter Five
                                                  • 50 CONCLUSION AND RECOMMENDATION
                                                  • • 51 Considerations in design
                                                    • 52 Community involvement
                                                    • 53 Recommendations
                                                    • • 60 REFERENCES
                                                      • APPENDICES
                                                      • • Appendix 1 HGL calculations
                                                        • Appendix 2 Moody chart
                                                        • Appendix 3 Standard pipes
                                                        • Appendix 4 Questionnaire sample