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Submitted to:Dr. Subrota Kumar SahaAssistant ProfessorES DisciplineKhulna UniversityKhulna

Submitted by:Group No: 22nd year 2nd termES DisciplineKhulna UniversityKhulna

Date of Submission: 2 October, 2005.

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Acknowledgement

All praise is to the Supreme Being; creator and ruler of the universe, God

whose mercy keep us alive and to pursue our education in Environmental

Science Discipline and to complete the assignment for the fulfillment of the

course Hydrology.

We would like to express our indebt ness to Dr. Subrota Kumar Saha,

Assistant professor, Environmental Science discipline, Khulna University.

For giving this assignment and under his guidance, encouragement, and

helpful suggestion make possible to fulfill this work.

On this auspicious occasion, we would like to grateful acknowledge the

support of the seminar library of Environmental Science discipline.

However, we are responsible for any remaining errors or inadequacies.

October, 2005 Group: 2

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ABSTRACT

Bangladesh, one of the most densely populated countries in the world,

inspite of severe resource, constraints, is trying to provide the basic

amenities like water supply for its population. It also faces massive urban

problems. All the urban areas are remote from planned community

facilities, like water supply, sanitation, sewerage system etc. Absence of

planning and automated technology generates a deplorable present and

future circumstance. Khulna city is an instance of having typical urban

problems particularly the crisis of water. Approximately 25% population

in this area is covered under piped water supply system while in the major

cities it ranges more.

In this study an attempt has been made to analyze the existing water in the

Khulna City Corporation (KCC) area. And to identify its defects and

deficiencies with suggesting possible remedial measures. The analysis of

present and future water demand and supply is also made in KCC area. It

shows that about 30 million gallon water per day is needed again the study

shows that the above 90% people use tube well both shallow and deep for

their drinking purpose.

The water potentiality of this area is especially dependent for the

development of the surface and ground water source. The environmental

concerns related to development of water supply system include depletion

of water resource, impact on agriculture and industry, disposal of waste

water and loss of land.

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CONTENTS

TOPICS PAGE NO

ACKNOWLEDGEMENT 2

ABSTRACT 3

CONTENTS 4-7

INTRODUCTION 8

BACKGROUND OF THE STUDY 9

OBJECTIVE OF THE STUDY 10

EVALUATION OF EXISTING

WATER SUPPLY SYSTEM IN KCC 11

SURFACE WATER SOURCES 11

GROUND WATER SOURCES 12

PRODUCTION SOURCES OF KCC WATER SUPPLY 13

HAND TUBE-WELLS 17

EVALUATION OF TREATMENT SYSTEM 17

STORAGE AND DISTRIBUTION 18

FACTORS RELATING TO THE WATER-

POTENTIALITY 20

REGIONAL SETTING 20

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GEOLOGY OF THE STUDY AREA 21

STRATIGRAPHY 21

LITHO LOGY 22

STRUCTURE 23

GEOMORPHOLOGY 23

HYDROMETEOROLOGY 23

RAINFALL DISTRIBUTIONS 24

RELATIVE HUMIDITY 27

WIND SPEED 28

BRIGHT SUNSHINE HOURS 28

EVAPORATION AND EVAPOTRANSPIRATION 29

HYDROGEOLOGY 30

DRAINAGE PATTERN 30

AQUIFER PROPERTIES AND HYDROGRAPHS-

AQUIFER PROPERTIES 31

HYDROGRAPHS 31

NATURAL RECHARGE 33

DEVELOPMENT OPTIONS FOR WATER SOURCES 35

DEVELOPMENT OF GROUND WATER RESOURCES 36

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DEVELOPMENT OF SURFACE WATER 38

DEVELOPMENT STRATEGY FOR SURFACE AND-

GROUND WATER SOURCE 39

33

ENVIRONMENTAL ISSUES 40

SUMMARY 42

CONCLUSION 44

RECOMMENDATIONS 45

REFERENCE: 46

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INTRODUCTION

Lack of safe water is more prominent in the third world countries. In

Bangladesh, like many developing countries, there is a great demand for safe

water. Water is available in country apparently almost everywhere but

availability of safe water is the prime question. Now, Khulna city faces the

same problem. Khulna is the third largest city and second seaport in

Bangladesh. It is situated in southwestern part of Bangladesh along the

Bhairab and Rupsha rivers. These rivers are affected by tidal conditions and

contaminated by various industries and municipal untreated waste disposal.

As a result, surface water is not frequently used for various purposes. Ground

water is available in and around Khulna city from the shallow and deep

aquifers, Withdrawn of ground water by well is the primary source of water

for KCC water supply system.

The KCC water supply system is primarily based on small groups of

production tube wells and one surface water treatment plant. There are only

five overhead tanks in the city but two are not active. The total system has

been developed over many years and has been constructed using relatively

small diameter pipes. Water Works Department of KCC currently recovers its

operating costs through the holding tax, connection fees for new services and

a flat monthly charge based on the size of service connection.

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BACKGROUND OF THE STUDY

Throughout history water has been considered a natural resource critical to

human survival and human history can generally be considered to be water-

centered. Human survival and welfare generally depend on regular

availability and control of water. The people of developed countries has

easily access to the pure and sufficient water usages where the paradox of

community water supply in developing countries is that everyone has access

to water supply, but in fact many people do not. They may have access to

water but only at a large walking distance, in too little volume or poor quality.

A lot of effort is made in the world to change this situation, but have we been

effective and this situation really- changing?

In 1981, KCC was able to provide 5 million gallons of water in a day. But it is

not enough to serve the urban population because the total demand was 15

million gallons (Islam, 1984). In the year 1991 water supply capacity rose to 8

million gallons but demand rose even higher and KCC was able to supply only

34% of the total demand (KDA, 1997). At present the total demand of water is

about thirty million gallons but the supply of water is half of this by which only

30% people are served (KCC, 2001). About 90% of the total populations of the

KCC area collect their drinking water from shallow and deep tube wells instead

of network water supply system from KCC (KCC, 1997). On the other hand, the

water supply management of KCC is not systematic and having limited

expansion capabilities which requires designing, constructing and managing to

face future challenges.

As a common characteristic of the urban areas of Bangladesh, accessibility to

the suitable quantity and quality of water is a major problem in KCC. Unplanned

and improper withdrawn of water is the main causes of the shortage of water.

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These shortages become more acute when pumps are installed haphazardly. In

some of the cases the supply system suffers a gross water loss from old pipes,

poor system control and excessive consumer wastage. Sometimes, the

consumers suffer frustration because of inadequate storage capacity of the

system and the intermittent supply.

OBJECTIVE OF THE STUDY

This study has intended with the followings objectives:

To evaluate the existing water supply facilities in Khulna City

Corporation area.

To evaluate the existing usage pattern of water and analyzing the water

supply and demand situation in KCC.

To ascertain the sustainable sources of ground water for the area.

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EVALUATION OF EXISTING WATER SUPPLY SYSTEM IN KCC

Oceans and seas are the main source of water but they are not potable.

Fresh liquid water sources from land surface and in the ground constitute

only 1 % of the total water on earth. In Bangladesh, safe water for drinking

and other needs is available in surface water of rivers, canals, ponds,

reservoirs and lakes and ground water in shallow and deep aquifers; ground

water is the most important source of water supply in our country rather than

surface water and for the salinity the water supply system of KCC is mainly

dependent on the ground water.

In Khulna city, the quality of drinking water is apparently a more serious

issue than the, supply water. The primary source of water supply in KCC

area is mainly from the ground water extracted through production and hand

tube wells. The secondary source of water supply is surface water extracted

from rivers, ponds and wells etc.

SURFACE WATER SOURCES:

Every year vast quantity of surface water from the Ganges and its

distributaries flows through two-river system in and around Khulna city, viz.

Rupsha and Bhairab for 6 months. Beyond this period i.e. in the dry season

the river water flow is reduced and affected by saline water intrusion from

the sea. Dakatia Beel has also been included as a source of surface water

supply. There are other numerous ponds which are used as surface water

sources in KCC area. The existing ponds in KCC area is shown in the Figure

1.

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Fig 1: Location of ponds of KCC

GROUND WATER SOURCES:

Ground water in and around Khulna is available in both shallow and deep

aquifers. The shallow aquifers are extended towards north of Khulna town

and well developed in the west of Dumuria thana. The depth of shallow

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Scale1:25,000

aquifers varies from 0~100 m. Phultala and Rupsha areas have a good

potential for abstracting shallow ground water with acceptable iron content.

The Jessore-Khulna-Bagerhat ridge running almost parallel to the river

Bhairab and having a maximum width of 6 km, has hydrological relationship

with the adjacent depressed lands known as Dakatia Beel.

The deep aquifers are generally present below 150-300m. Water from

deep aquifers is almost pure and safe for drinking purpose and less

vulnerable to pollution from industrial waste and spillage. The contents of

iron and manganese are within permissible limits of WHO or Bangladesh

standard Investigations suggest that untapped ground water supplies are

available from around Khulna city, particularly Dumuria area.

PRODUCTION SOURCES OF KCC WATER SUPPLY

There are currently 43 production wells in operation. Total installed

capacity of the wells is in excess of 35,000 m3/ day but the yield to the

system is considered significantly less because of operating condition. Most

of the wells with some few exceptions in shallow aquifer are 150mm

diameter deep tube wells at an average depth of 275meters. Service is

intermittent as the pumps are operated for a maximum of 13 hrs in a day

divided into two shifts. These service periods are frequently interrupted,

which reflects reduced supply and level of service to the consumers. An

inventory of production wells was undertaken in 1994 which resulted that

there is a need for consideration of either rehabilitation or replacement of

worst performing wells in KCC. Production wells in KCC area are indicated

in Table 1 and drinking water production tube wells are indicated in fig 2.

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Serial no Location of well

Well no.

Year installed

Total depth (m)

Pump capacity m3/hour

1. Khalispur-1 1 1963 85 682. Khalispur-3 3 1973 238 683. Gollamari 10 1981 276 1364. DPHE/Rupsha-1 16 1982 201 685. R&D Compound 18 1982 253 686. Azam khan comm.college 19 1983 276 327. Circuit house 22 1983 198 688. Feri ghat-2 23 1983 256 689. Bagmara 24 1983 265 6810. Pollimangal 25 1984 262 6811. Khalispur pourashava 26 1984 226 6812. Taltala city college 27 1984 210 6813. DPHE/Rupsha-2 28 1985 197 4514. Hadis Park 29 1986 210 6815. Khalispur-5 30 1987 247 6816. Islamabad comm. Center 31 1987 270 6817. Sheikh para-2 32 1988 169 6818. Tutpara well field-1 33 1987 201 6819. KDA Nirala-1 34 1987 251 6820. KDA Nirala-2 35 1987 232 6821. KDA Nirala-3 36 1988 253 6822. Tutpara well field-2 37 1988 198 10223. Tutpara well field-3 38 1986 274 7024. Mujganni well field-1 39 1986 290 7025. Mujganni well field-2 40 1986 253 7026. Mujganni well field-3 41 1987 281 6827. Sisu park-2 42 1988 234 7028. Shonadanga 43 1987 283 6829. Arambag 45 1987 286 7030. Tarerpukur-2 46 1994 250 6831. Municipal tank road 47 1994 281 6832. Khalispur sewerage 47 1994 268 6833. Khalispur TV center 48 1994 254 6834. DPHE/Rupsha-3 49 1994 212 6835. Nurnagar 50 1994 245 6836. Zilla high school 51 1995 245 7037. Islamabad comm. Center 52 1995 274 7038. East Baniakhamar 53 1995 285 13039. Feri ghat 54 1994 323 7040. Khalispur (near club) 55 1995 266 6841. Alia Madrasa compound 56 1994 282 6842. Mosselman para 57 1994 214 6843. Sonadanga near police fari 58 1994 245 68

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Table 1: KCC Production tube wellsSource: KCC (2000)

Fig 2: Location of the drinking water production tube-wells and Selected holds in the KCC area.

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HAND TUBE-WELLS

The KCC statistical current information shows that KCC have 5650

hand tube wells of which 3800 are shallow and the remaining 1850 are deep

tube well. The yields of these tube wells were estimated by Haskonning 1981

as 3.3 m3/day for the shallow wells and 6.6 m3/day for the deep tube wells

estimates with this consultant concerns. The Table: 2 reflect the total picture

of tube wells.

Table 2: KCC Hand Tube wells

Descrition No. of wells Capacity (m3 /day)

Deep Tube well 1850 6.6Shallow Tube well 3800 3.3

Total 5650Source: KCC (2000)

It can be observed from the accompanying table that more than 4% of

both shallow and deep tube wells of KCC are not working. The status of

shallow and deep tube wells is shown in Table 3.

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Table 3: Status of Tube wells

Ward No.

Deep Tube wells Shallow Tube wells

Working Not workingWorking Not working

1 5 256 22 3 254 13 3 332 14 39 72 15 3 190 26 3 246 27 3 173 48 7 164 99 61 7 2

10 30 1 128 511 3 1 153 412 14 1 131 413 3 134 314 84 8 315 25 61 1016 82 13 -17 76 30 318 57 3 4 -19 43 7 21 420 57 5 35 821 42 3 68 1222 76 4 66 823 47 2 64 124 71 4 33 825 52 1 16 126 46 2 22 l27 57 57 45 528 56 1 29 229 44 21 4

30 643 45

14

31 83 7 2 4Total 1239 53 2761 128

Source: WWD, 2000

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EVALUATION OF TREATMENT SYSTEMThere is one surface water treatment plant. In 1921, it was founded in the old

city opposite the KCC office In this plant, raw water is pumped from the river

of Bhairab and delivered via rising main to a primary settling pond. Water is

pumped from the settling pond to two secondary settling tanks designed for

coagulation and settlement after mixing with a solution of own. The capacity

of each settling tank is such that a two hour sedimentation time is allowed.

Water from the settling tanks is then loaded into a single rapid sand filter

where the present filtration rate is 34 m3/hr. The treated water is then passed

underground storage tank. The water is finally pumped into a steel overhead

tank which is now in poor condition; water from the overhead tank is also

used to backwash the filter bed.

The treatment works operate for only seven months of a year, due to

salinity in the river during the dry season. The treatment plant is normally

operated for an average of 8 hrs per day and produces treated water of about

450m3/day. This amount is less than the yield of one newly installed

production well. Again, the production tube-wells are away from the

treatment system.

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STORAGE AND DISTRIBUTION

Storage Facilities Reservoirs

There are five elevated water storage tanks with a total capacity of

2815 m 3 but now three are running. The location of tanks is shown in

Figure 3 and Table 4 shows the inventory of existing overhead storage

tanks in KCC area.

Table 4: Inventory of Existing Overhead Tanks

SL. No. Location

Height of tank fromGL(m)

Maximumwater

level(m)

Storagecapacity(m3)

Material ofconstruction

1 Water Works 15.2 19.2 91 Steel

2 Ferry ghat 23 27.4 909 R.C.

3 H&S New colony 18.3 22.0 680 R.C.

4H&S Khalispur lal

hospital18.3 22.6 455 R.C.

5 DPHE 26.2 28.7 680 R.C.

Total 2815

Source: KCC (2001)

The main sources of water supply in KCC area are ground water. Above 90

percent usage water is extracted from the ground with the help of production

tube-wells, deep and shallow tube-wells and other private tube-wells. There

are only one surface water treatment plant which generates 450 m 3 /day and

43 production tube-wells. Besides, there are five overhead tanks and 262 km

of distribution lines.

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Over head tankPump houseRail wayHigh wayWard boundaryRiver

FACTORS RELATING TO THE WATER POTENTIALITY:

The occurrence movement and storage of ground water are governed by the

Litho logy, geological structure, thickness and depth of occurrence of

different geological formation along with the tectonic activities prevailing in

the area. The ultimate source of most dissolved ions in water is the mineral

assemblage in rocks near the land surface. The purity of crystal -size of

minerals, the rock texture and porosity, the regional structure, the degree of

fissuring and a good number of other factors might influence the composition

of water passing over and through the rock (Hem, 1970).An understanding of

Landscape and its formation is essential for the demarcation of catchments

boundaries, assessment of surface and subsurface water resource and the

planning of water development projects for irrigation development. All these

are relates with geology of that area. Hence the important role of geology in

assessing the hydrology and hydrochemistry of an area cannot be over

emphasized.

REGIONAL SETTING

Khulna city is located on the banks of the Rupsha and Bhairab rivers. It is

in the south west part of Bangladesh with it’s location on the axis of

jessore-mongla port, the second largest seaport of the country.

Geographically, khulna lies between 22o 49/ north latitude and 89o 34/ east

longitude and it’s elevation is 7 feet avove MSL. Khulna is bounded by the

Bhairab and Fultala thana, on the east by the Rupsha river, on the south by

the Rupsha river and on the west Dumuria thana. Figure shows the location

of the Khulna city in context of Bangladesh and Khulna district.The Study

area is mainly covered by the Ganges deltaic deposits and paludal deposits of

Quaternary age (ALAM, et. al., 1990). The deltaic deposits comprise of tidal

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FIG 3: Location of Pump House and Over Head Tanks

deltaic deposits, deltaic silt deposits and mangrove swamp deposits. The

southern part of the study area is low lying area, whereas the land level of

northern part is comparatively higher. The major portion of the area lies

between five and seven feet (1.5 and 2.1 meters) above the average sea level.

The northern part of the city is above the normal flood level. But the areas

lying at south east and west area usually inundated during the rainy season.

GEOLOGY OF THE STUDY AREA

Khulna is situated in the delta region and delta is divided into moribund delta,

central delta, basin immature delta, mature delta and active delta. Khulna is in

the immature delta. It is possible that subsidence has played a major part in

depressing this area There are many evidences of it, such as large ruins in the

heart of the swampy estuarine areas such as at Shekertek and Bedkashi

(Fawcus,1927), and presence of human artifacts and tree stumps, buried in the

alluvium many feet below the level of the sea. Hunter (1875) recorded the

presence of large tree trucks buried in the ground at Khulna town, indicating

subsidence of 6m.

STRATIGRAPHY

The Study area is covered by Holocene river alluvium comprising deltaic, terrace

meander, inter stream and swamp deposits. These Sediments continue to

accumulate from detritus deposits by the main river, particularly on the flood

plain of the Meghna. Tidal deltaic deposits are light to greenish gray,

weathering to yellowish gray, silt to clayey silt with lenses of very fine sand

along active and abandoned stream channels including crevasse splays, and

contain some brackish water deposits. Deltaic silts are light gray to gray, fine

sandy to clayey silt. Mangrove swamp deposits are found in the southern

margin of the study area. These are dark gray to black silt and clay deposited

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in the active tidal zone which is dominated by woody organic rich mangrove

swamps. Marshy clay and peat deposits occur in the central, northeastern and

northwestern side of the study area. They are gray and black herbaceous peat

and yellowish grey silt. There is no specific evidence of wells in the Study area

because of there general similarity in Litho logy to Holocene sediments and

lack of fossil evidence although the Sediments become progressively older

with depth.

LITHO LOGY:

The litho logy of the various sediments referred to above varies from clay,

through silt, to fine, medium and occasionally coarse sand The geometry of

individual Sedimentary units is inevitably complex and there is a general lake

of horizontal continuity on a local scale. Also, there is an upward finding of the

sequence, while the degree of sorting decreases with depth. Table 5 Show an

arbitrary subdivision of subsurface strata of the study area based on litho logy

and electrical-log.

Table 5: Stratigraphic Succession in Khulna (ALAM, et.a1.,1990)

Age Study area Lithology Thickness

Quaternary Khulna Clay, silty clay with occasional very

fine sand and traces of micas

13-65 m

Silt, silty sand, sandy clay, very fine to

fine sand, fine to medium sand

18-92m

Caly, silty clay, fine sandy clay 31-188m

Silty clay, fine to medium sand, 10-165m

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medium sand, some course sand

Peat is located in the deltaic pale is known from Kala Mouja in the Khulna

district (Ahmad, 1969, 7aher, 19G2): This peat bed has a thickness ranging

from some few centimeters to about 3.5m. This type of peat is highly humified

and its dark brown color indicates advanced decomposition of the organic

matter.

STRUCTURE

Major regional Structural feature of the Bengal Basin have been investigated

as part of oil/gas and mineral exploration, and various troughs, saddles and

faults can be identified within it. However there are no apparent major

structures within the Pleistocene to Holocene sediments of project area, such

as faults and folds, which would be hydrologic ally significant.

GEOMORPHOLOGY

Geomorphologic ally, the study area lays in the Ganges tidal flood plains.

In the Khulna all the soils are developed in alluvial sediments laid down by

the river Ganges. Most of the soils are seasonally shallowly flooded, grey to

dark gray in color with variable amount of brown and yellow mottling and

are silt to clayey in texture (SRDl, 1973) of Bangladesh.

HYDROMETEOROLOGY

The climatic condition of an area can be evaluated through analyzing the

climatic and hydrologic data. The climate and hydrologic data include

rainfall, temperature, humidity, atmospheric pressure, sunshine , wind

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speed, evaporation, transpiration, etc. among which the rainfall,

evaporation, transpiration component have a direct role in the hydrologic

balance and they are relevant to the hydrologic cycle of an area . The

climatic condition of an area has much influence on quality of water not

only in amount and kind, but also in the annual regime of water quality

fluctuation (SANTOS 1972). Hassan (1992) constructed the following path

of hydrologic cycle for South part (Khulna, Jessore ) of Bangladesh (Figure

4}and possibly it is the best fitted in Bangladesh.

Figure 4: Hydrological cycle for Bangladesh after (Hassan,1992)

Explanation: R= Rainfall, R-0= Runoff, E= Evaporation, T= Transpiration, I= Infiltration, PC= Percolation, EF= effluent, INF = Influent, O-F = out flow, Cp = Ca pillory Pressure and Sp = Seepage

RAINFALL DISTRIBUTIONS

Rainfall is an important component of hydrologic cycle. It is also the input

component of the hydrodynamic System of an area. Both the surface water

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and groundwater of an area could be derived from this component alone.

Less rain create imbalance in the hydrologic budget of an area while heavy

rains produce flush flood causing damage to humidity i.e. agricultural

products and others. Thus a long term rainfall distribution statistics through

out the year is very important for the local agro climatic condition which will

help in making the agricultural planning of an area (Hassan,1994).

Khulna receives an average rainfall of about 1800mm. The main source of

rainfall is the southwestern monsoon. Nearly 81 per cent of total rainfall

occurs during June-October. During March-May some rainfall also occurs due

to Nor'wester effect. Winter is the dry period with little or nearly no rainfall.

However, during the months of December and January little rainfall is

recorded. The monthly rainfall variation in Khulna city is shown in the Figure

3.2. (Environmental Maps and Work Book for Khulna City, Bangladesh)

Figure: 5 Monthly Rainfall (in mm) in the year of 2000 (Meteorology Department)

The mean annual rainfall is 1692mm at Khulna. The mean monthly rainfall

varies from 2mmto 341 mm. Other seasonal rainfall distributions on Khulna

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monthly rainfall in mm

0100200300400

month

rain

fall

in

mm

rain

are represented in the Table6. About 90%of its mean rainfall in Khulna was

received in May-October (monsoon period) and rest 10% of rainfalls was

received in November April (Non monsoon period).

MonthRainfall(mm)

Temperature(oC) RelativeHumidity( %)

Brightsunshine (hr) Maximum Minimum

January 2 26.25 11.6 73.63 212.6February 40 28.65 15.55 70.9 220.03

March 19.5 31.35 20.15 71.57 272.25

April 75.5 34.85 24.2 75.7 204.5

May 194 34.7 24.8 80.56 183.4

June 286 31.9 25.7 90.15 113.05

July 341 31.95 25.85 88.57 142.55

August 241 33.1 26.3 85 172.2

September 271.5 32.8 24.9 87.65 159.5

October 206 32.9 24.85 88.68 196

November 15.5 30.7 20.85 83.09 205.3

December 2 25.55 13.65 80.57 213.65

The recorded minimum mean monthly rainfall was in the month of

December which is 0.12mm (0.12%of total rainfall) and the maximum mean

monthly rainfall was in the month of July which is 341mm(20.14%of total

rainfall)About 80% of rainfalls were received in annually within the

Monsoon period(June to October) in Khulna . Considering the rainfall

intensity, it is seen that over 250mm/month of rainfall were received in the

May-October months of the year and this duration may be termed as wet

month. The rest months of the year may be considered as non monsoon in

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Table 6: the monthly average climatic data in climatic in Khulna region

Source: Meteorological department, 1997-2001

which less than 30 mm/month of rainfall were received from November to

April.

RELATIVE HUMIDITY

Relative humidity is inversely proportional to the temperature. Higher the

temperature lesser will be the relative humidity of the atmosphere. The

region has high relative humidity. In Khulna area the mean monthly relative

humidity varies from 90.15Qune) % to 70.90% (February) and the mean

annual is 81.35%. Tab le 6 gives the mean monthly relative humidity in

percent of Khulna and Figure 6. shows the monthly relative humidity

variation and Figure: 7 the relationship between relative, humidity and

temperature of Khulna.

Fig 6: Monthly Variation of Relative humidity (%) in Khulna

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relative humidity

020406080

100

januar

y

mar

chm

ay july

sept

embe

r

nove

mbe

r

relativehumidity

Y=0.331X -0.5402R2=0.3315

0 20 40 60 80 100Relative humidity (%)

Fig 7: Correlation between Temperature (0C) and relative humidity (0C) in Khulna

WIND SPEED:

Wind speed data at the meteorological office is reported as an average for

the day in Knots for the predominant wind direction of at 10m height. The

records indicate a significant variation in the mean wind speed across the

region. The monthly distribution of the wind speed also varies.

BRIGHT SUNSHINE HOURS

Bright sunshine is the important parameter in controlling the climatic

condition of an area. The air pressure of an area depends on the bright

sunshine and thus it control the wind blow(Direction and speed), evaporation

rate etc .The mean monthly bright sunshine in Khulna varies from 113.05

hours to 272.25hours in June and March respectively. The mean monthly

bright sunshine in Khulna is given in the T'able6, and the monthly brightly

sunshine variation is shown in the figure 8.

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Figure 8: Variation of monthly bright sunshine (hrs) in Khulna

The Study area experiences a wide variation in the distribution of sunshine

hours, ranging from a mean annual minimum of 5.2 hours of to a maximum

of 7.0 hours. As would be expected the sunshine hours in the monsoon from

June to September are much lower than during the rest of the year where in

excess of 8.5 hours of sunshine are not uncommon.

EVAPORATION AND EVAPOTRANSPIRATION

The evaporation and transpiration data along the rainfall are required to study

the hydrologic balance of an area. Evaporation is depended upon the

temperature condition of the atmosphere and it is directly proportional to the

temperature i.e., higher the temperature greater the evaporation. The estimated

mean maximum evaporation in Khulna area was 4.33mm/d (April), and the

mean annual evaporation was 2-mm/d. The Khulna area, the mean monthly

evapotranspiration varies from 2.67 mm/d (January to 5.12mm/d (April) and

the mean annual is 3.49mm/d.

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HYDROGEOLOGY

Hydrogeology is the Study of geological factors relating to the earth's

Water. The traditional Studies in hydrogeology focused on either the

mathematical treatment of flow through porous media or on a general

geological description of the distribution of rock formation in which ground

water occurs. Therefore the optimum development and management of

groundwater resource for mitigation human requirements must be

dependent on the proper investigation of the water bearing formations on an

area and its properties and characteristics (Bowen, 1986).

DRAINAGE PATTERN

The Study area is mainly drained by the Bhairab, Rupsha, and Pasur river

and numerous minor tidal; streams. These (Bhairab, Rupsha, and Pasur) are

actually a same river course but have different names in different locations

during their courses and gradually found their way by a Southerly route to

the Bay of Bengal. The Bhairab River, the most important river of the Study

area, enters the Study Area from the north near Phultala and flows in a

south easterly course at the northern part of Khulna district. It then passes to

the south, discharging a great part of its water into the Rupsha or Pasur,

while the main channel runs to the Southeast part Fakirhat and Bagerhat and

joins the Madhumatiat Kachua near Khullna. Bhairab is joined by the

Atharabanki which covers the surplus Water of the Madhumati into the

Bhairab.

- 31 -

AQUIFER PROPERTIES AND HYDROGRAPHS AQUIFER PROPERTIES

Aquifer parameter data for the Study area are relatively Sparse. Based on

Pump test Data the aquifer properties of the upper aquifer namely

transmissivity of Khulna city area is 3900m` and the Storage co-efficient is

2.O× 103. Based on litho logy the Specific yield of upper aquifer is

16.60%.

Table7: Aquifer properties of The Upper aquifer of the study area:

Location Derived from

Litho logy

Derived from pumping test

Specific yield in

%

Transmissivity

in m2/day

Storage co

efficient×10 -3

Khulna 16.60 3900 2.0

Source: HASSAN, 1992 GWC, BWDBI 1985 &1986

HYDROGRAPHS:

Ground water observation wells monitored by BWDB and other

organizations concerned with ground water development show a pattern

which is characteristics of other alluvial areas in Bangladesh.

The characteristics Hydrographs pattern is:

A variation in ground water levels corresponding to the wet and dry Season;

Lowest water levels at the end of the dry Season in April/May;

A rapid rise following the onset of the rain, to field capacity (aquifer -

full condition) in the wet Season;

- 32 -

A dry Season recession, to complete the cycle.

In many cases the lowest recorded water level during April, when the onset

of the rain was usually late. Hydrographs over a longer period often show a

general trend of increasing maximum depth of ground water. As a result of

increased pumping for irrigation. However, aquifer-full conditions are

always established during the wet season so it is also a process of storage

manipulation to increase recharge and is there fore a beneficial effect.

- 33 -

NATURAL RECHARGE

In the contest of the alluvial aquifer of Bangladesh, the usual method of

evaluation of available ground water resources is based on a calculation of

recharge. Recharge is the process by which water infiltrates during the wet

season and restores in the groundwater levels to field capacity. It is usually

expressed as a depth of water per unit area, or as a seasonally available

volume. The groundwater System in the Study Area is considered to be in

hydrodynamic equilibrium condition, that is, the annual discharge is

approximately equal to the annual recharge. Recharge exceeds the discharge

during the monsoon period and the ground water rises but during the dry

season recharge is considerably less than discharge and then the ground water

levels decline. The Area under study, the primary source of natural research are

taken to be direct infiltration of rainfall and flood waters during monsoon,

other potential sources such as ground water inflows are considered to be

negligible(UNDP,1982: MPO/Harza, 1986). This water infiltrates. and fills the

unsaturated zone created by the dry season groundwater level recession. The

following component and processes are involved in recharge and discharge

mechanism of the ground water System of the study area as well as Bangladesh

(I-IASSAN, 1992).

Recharge (R) . Input

Components Processes

Rainwater Runoff, infiltration and percolation

Floodwater Runoff, infiltration and percolation

- 34 -

River water Infiltration and percolation

Seepage water Infiltration and percolation

Discharge (D) : out put

Components Processes

Artificial flow By using different types of tube ells.

Natural Flow By Steam flow activity (to river ponds and canal etc)

Capillary rise By differential atmospheric pressure

Evapotranspiration By heat, temperature and light.

In Bangladesh , about 26% of the total annual groundwater recharge is being

lost by discharging into cannels, streams and rivers before the start of the

irrigation season in the month of November (KARIM, 1982) The runoff has

been estimated as 20°'o to 40°'0 of the excess(P-PF) rain fall (UNUP,

1982).Considering the topographic configuration of the study area it may be

assume as minimum of 20% runoff of the excess rainfall that is equivalent to

138.53 mm/anam.

The estimated annul ground water recharge of the study area is about 196.2

million cubic meter, it can be considered as actual ground watrer research of

the study area. The available ground water recharge within this period can be

calculated by 26% deducted from the annual ground water recharge that is

equivalent to 145.18 million cubic meter of the area.

- 35 -

DEVELOPMENT OPTIONS FOR WATER SOURCES

General Considerations for Water Resource Development

To develop the KCC water supply system we should keep in mind the same thinking because it is not apart from the horrific water deficit. We should stress the need for striking a balance between use of ground water and surface water.

Identification of potential ground and surface water sources for future

water supply of KCC is very essential and the evaluation is based on

the following criteria:

• Reliability and quality

• Sustainability

• Finance and economy

• Implementation consideration

• Environmental impact

• Institutional aspects

The following broad options are considered:

i) Development of ground water resources as a sole source of supply.

ii) Development of surface water resources as a sole source of supply.

iii) Development of a combination of surface and ground water resources

(conjunctive use).

- 36 -

Since the supply of water from the existing hand tube-well/production tube-

well is likely to go down, additional sources of ground water and new

potential well fields made to be explored immediately. New sources of water

resources also include availability of surface water from rivers in and around

Khulna city. Beel as a natural reservoir of surface rainwater, need

investigation to explore the possibility as a source of supply of potable water.

Surface water from natural rivers also needs evaluation as new and additional

sources of water. The ponds and lakes should be conserved as a surface water

source for KCC area.

DEVELOPMENT OF GROUND WATER RESOURCES

Ground water in and around Khulna is available in both shallow and deep

aquifers. The shallow aquifers are extended towards north of Khulna town

and well developed in the west of Dumuria Upazilla and the deep aquifers

are generally present below 150 to 300 m. The deep aquifer has been

intensively exploited by production wells of KCC and to some extent by

industrial well and private hand tubewells.

Ground water supplies are available from the following sources within

reasonable distance from Khulna city which are shown in Figure 9.

(i) Khulna city area

The previous modeling study monitoring data suggest that a continuous

abstraction of 59000m;/d of fresh water could be maintained for decades.

However, at present the shallow aquifer is only a reasonable source in the - 37 -

northern half of the city. The shallow aquifer has been developed by a few

production wells, numerous hand tubewells and many private motorized

tubeweils.

Fig 9: Potential ground water sources in and around Khulna city

(ii) Rupsha area

- 38 -

There are shallow ground water resources in this area. This area is expected

to grow rapidly after construction of the proposed Rupsha Bridge over the

Rupsha river. Therefore, the ground water resource can be developed in the

future for the local needs.

(iii) Dumuria area

Both deep and shallow ground water are available in central Dumuria. At

present shallow tube-wells are used for irrigation purpose, which indicate,

that there is a very high productive shallow aquifer in the west of Dumuria.

This source has probably highest potential ground water resources around

Khulna city (MSP, 1997).

(iv) Khalishpur-Phultsia area

Both deep and shallow aquifers are available in the same area within a strip

of a few kilometers wide from the northern part of Khutna city to Ahultala

and beyond towards Jessore. The shallow aquifer runs almost parallel to the

river Bhairab and on either side of the Khulna-Jessore road. The water

quality in both aquifers is good. The transmission distance and pipe lines to

augment city water distribution system will be less and so the development

of ground water resources (both deep and shallow) in the area will be most

economic option for meeting the city demand. Short and medium term needs

of the city can be met by developing new wells in the area.

DEVELOPMENT OF SURFACE WATER

Surface water from the Ganges and its tributaries flows through the rivers

Rupsha and Bhairab for six months. In the dry season the river water flow is

reduced and affected by saline water intrusion from the sea. Besides, Dakatia

Beef can be developed as a potential surface water sources for the KCC.

- 39 -

The delivery of fresh water from the river and surface water can be made

through the following methods:

i) By constructing a barrage at a location where saline water intrusion can be

checked. But it involves high cost for construction, operation and

maintenance;

ii) By developing a regional water supply system through potential

surface water resources; utilization of surface water stored in natural

depression / water bodies.

The Mayur river from Gallamri to Rayermahal has been developed as

water based recreational open space. This can also serve as a water

reservoir to meet the daily water consumption needs of the city dwellers.

This will necessitate to re-excavation of and protection of the rivers

supported by a treatment plant. The supply from this reservoir can be

linked with city water supply network.

DEVELOPMENT STRATEGY FOR SURFACE AND GROUND WATER SOURCES

It is considered that the general strategy for further sources development

should follow the principles summarized below:

(i) Short term (0 to 5 years)

• Continuation of use ground water from the deep aquifer in and around

Khulna;

• Development of new well fields for extracting water from the aquifers

north of Khulna in Khalishpur and Phultala area;

• Monitoring and evaluation of the impact of ground water development and

increasing abstraction.

(ii) Medium term (6 to 15 years)

- 40 -

• increased with drawl from the shallow and / or deep aquifers;

• Further development of new wells fields for extracting water from

the aquifers north of Khulna in Khalishpur and Phultala area;

• Continued monitoring and evaluation of the impact of ground water

development and increasing abstraction.

(iii) Long term (over 1.5 years)

• Further exploitation of available ground water resources in and around

Khulna;

• Continued monitoring and evaluation of the impact of ground water

development and increasing abstraction;

• Construction of a surface water abstraction and treatment plant for.

conjunctive use with ground water abstraction if or when required by the

inability of the ground water sources to meet the demands.

ENVIRONMENTAL ISSUES

Overview

The rehabilitation and expansion of the Khulna city water supply system

raises a number of environmental concerns which will be addressed at the

design stage. Though Bangladesh is continually threatened with inundation

and water is to be seen everywhere,

it is no longer a limitless resource which can be squandered. A combination

of increased water demand for agriculture, industry and domestic use, the

contamination of many sources by pollution, and decreased dry season supply

due to upstream diversion in India, has made water into a limited resource to

be husbanded and used efficiency.

- 41 -

The planned expansion of the capacity of the public supply system represents

both a significant increases in per capita demand and coverage of the

population. This results not only a major increases in demand in available

water sources but is likely to lead to a major increase in the releases of

polluted waste water.

System losses represent a tremendous wastage of valuable natural resources

which can not be afforded by Bangladesh. Therefore, the reduction of water

losses to an acceptable level is a critical mitigation measure required to make

the project sustainable, economic and environmentally acceptable.

The environmentally concerns related to the expansion of the Khulna Water

Supply therefore cover the following areas:

- Depletion of water resources;

- Impacts on competing water users (i.e. agriculture and industry) - disposal

of waste water; and

- Other impacts, including loss of land and resettlement for locating reservoir

and other water supply facilities.

The critical mitigation measure is water conservation, including the reduction

of system losses and wastages.

There are alternative sources include:

i) ground water,

ii) Surface water and

- 42 -

ii) Conjunctive use of ground water during the dry season and surface

water during the rainy season. The ground water withdrawal involves

the use of both shallow and deep aquifers.

Shallow aquifers are found to be fully recharged during the rainy season, and

the major concerns with the shallow aquifer are the possibilities of salt water

intrusion and contamination of the aquifer by effluent released at the surface

or to leach pits. The major concern with the deep aquifer is that withdrawals

should not exceed die safe yields of the aquifer. To be environmentally

sound, the impacts of water withdrawal on the aquifer should be carefully

monitored over the short term to determine the impacts of sustained

abstraction.

The use of surface water as a year-round source would involve the

construction of barrages, reservoirs, and water treatment plants. These

require the allocation of significant land areas which will diverted from other

productive uses such as agriculture, will interfere with natural river system,

and are likely to require the resettlement and the finding of alternatives

livelihood for a number of families. They therefore have the potential for

significant negative impacts.

Conjunctive water use, which involves the use of sweet water from the

Bhairab river during the rainy season and ground water during the dry season

when the Bhairab is saline, would significant reduce demands on ground

water aquifers. The allocation of areas for treatment plants and reservoirs

would be needed but such areas would be significantly less than required for

the year round use of surface water option. The conjunctive water use option

is therefore considered to be the most appropriate in the long-term to

maintain a sustainable water supply for Khulna with minimum negative

impacts.

Conservation

- 43 -

The existing water system in Khulna is extremely wasteful in term of water

losses. From an environmentally point of view, reducing wastages is a

critical issue, and environmentally acceptable option should be based on an

effective water conservation program.

Wastewater

Increasing water supplies will result in greater discharges of wastewater

which could significantly contribute to the contamination of surface and

ground water. Of greatest concern is the potential for contamination of the

shallow aquifer under the city. This could cause in a public health risk

leading to the need for water treatment or the possible abandonment of the

affected aquifer as a water source, resulting in increased demands of the deep

aquifers. To minimize the risks of contamination, an appropriate sewerage

system for collection and disposal of sludge and wastewater should be

seriously considered in conjunction with any major water system expansion

programme.

SUMMARY

To develop water supply system, there is need an identification of potential

ground and surface water sources in and around Khulna city and to develop

the collection system i.e. most of the existing wells should be tested. Besides,

the treatment and distribution system can be developed with the help of

proper technology. Again, there is need some policies to maintain the water

supply system i.e. incorporation of GIS and water policy etc.

- 44 -

CONCLUSION:

Khulna is having a tropical monsoon climate characterized by high

temperature heave rainfall, often excessive humidity and fairly marked

seasonal variations. The mean annual 1997 to 2001 rain fall is 1692.5 mm

about 90% of the annual rainfall were received from May to October. The

minimum is observed in the months of January and December (0.12%) and

the maximum in the month of July (20.14%).The mean maximum

temperature in Khulna in the month of April (34.85 oC) and the minimum in

the month of January (11.6 oC). The mean relative humidity of Khulna is

81.35% and the mean monthly sunshine in Khulna is 191.2525 hours.

For the development and management of water resource of the study area, A

detailed climatologically, hydrological, and hydro-geological and hydro-

chemical subsurface mapping is necessary to be considered. The tropical

monsoonal climate characterized by relatively high temperature, heavy

rainfall, excessive humidity etc is suitable for the ground water potentiality.

- 45 -

RECOMMENDATIONS

From the study it becomes clear that the water potentiality of KCC area is

depend upon ground water source, surface water source and a surface water

treatment plant. But this is not sufficient for the KCC area people. So this is

very important to develop water system of KCC area. Here some points are

giving for developing water System for Khulna City Corporation area.

Establish new water well and water reservoirs.

Proper use of water resources.

Rain water harvesting.

Waste water treatment.

Proper use of surface water.

Less ground water withdrawal.

All storage tanks should be properly managed.

Development of water supply system.

Special attention should be given to ensure that service connections

don’t have any linkage.

Storage tank should be fitted with suitable taps to avoid the possibility

of loss of water.

And overall rising of social consciousness.

- 46 -

REFERENCE:

1. Nazim Uddin, M., 2002, “A Study on water supply system of

Khulna City.” Environmental Science Discipline,

KhulnaUniversity, Khulna. (Thesis Paper).

2. Sultana Nasrin, 2003. “Physico-chemical and

Microbiological Aspects of Drinking water- A Case Study on

Khulna City Corporation, Khulna, Bangladesh”.

Environmental Science Discipline, Khulna University,

Khulna. (Thesis Paper).

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