pmp estimates for kalpasar project in gulf of khambhat (india)20 mahi banswara arthuna 23.50 74.08...

IJSRD - International Journal for Scientific Research & Development| Vol. 5, Issue 02, 2017 | ISSN (online): 2321-0613

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PMP Estimates for Kalpasar Project in Gulf of Khambhat (India)

Dr. Surinder Kaur1 P. K. Gupta2

1Assistant Professor 2Student 1,2India Meteorological Department, New Delhi-110003, India

Abstract— Gulf of Khambat is an inlet of the Arabian Sea

along the west coast of India, in the state of Gujarat. Gujarat

is a water deficit state specially the Saurashra region which is

rocky and barren. The annual per capita water availability is

540 cubic meter in Saurashtra region which is much below

the minimum requirement of 1700 cubic meter. To store

surplus/untapped surface water, the Govt. of Gujarat proposes

construction of Kalpasar project in the Gulf of Khambhat

which is an eligible option that can store fresh water of the

rivers of Dhadhar, Mahi, Sabarmati from one side and some

of the Saurashtra rivers from the other side. This will be the

world’s largest man made fresh water reservoir in the sea. For

construction of reservoir, the design storm estimates are

required for computation of design flood. In this paper, the

design storm estimates in the form of Probable Maximum

Precipitation (PMP) estimates have been computed for the

Kalpasar project in the Gulf of Khambhat.

Key words: Gulf of Khambhat, Kalpasar, SPS, PMP

I. INTRODUCTION

Gujarat is the western-most state in India which occupies the

northern extremity of the western sea-board of India. It lies

between latitude 20º07' and 24º43' N and longitude 68º10' and

74º29' E. The state is bounded by Pakistan in the north-west

and the state of Rajasthan in north. To the east it borders

Madhya Pradesh, and Maharashtra. The Union Territories of

Daman, Diu, Dadra and Nagar Haveli lie to the south of

Gujarat. It has 1600 km long coast line by the Arabian Sea

forming the western and south-western boundary. Gujarat is

a water deficient State. The annual rainfall in the state varies

significantly. The mean annual rainfall ranges between 300

mm to 2800 mm. Normal rainfall of the state is 720.6 mm.

The normal rainfall of Gujarat region is 1107mm and of

Saurashtra and Kutch is 578mm. The state has 6.4 % of land

area of the country and 5% of the country's human population,

but its surface water resource is only 2% of the country. The

annual per capita water availability is 990 cubic meter in the

State which is much below the minimum requirement of 1700

cubic meter. However, even after

including Sardar Sarovar Project (SSP), only 20480 million

cubic meters (54%) is possible to store. There is no suitable

site of land in the State available for the creation of river

valley project to store surplus / untapped above 40% surface

water. In such a circumstance, the Govt. of Gujarat proposes

to create a reservoir by construction of a Gulf closure dam in

Gulf of Khambhat which is an eligible option to store about

10,000 million cubic meter water inflows of the rivers

( Dhadhar, Mahi, Sabarmati and some of the Saurashtra),

which accounts for 25% of total surface water resources of

Gujarat. Creation of this fresh water reservoir does not

involve any land acquisition or rehabilitation of people, and

will serve as a life line of the Saurashtra region as well as an

accelerator for the growing economic activities

of Gujarat State. This will be the world’s largest man made

fresh water reservoir in the sea and may be used for irrigation

and drinking water for Gujarat specially Saurashtra region.

The Gulf of Khambhat extends from north to south

about 200 km and the width varies from 25 km at the inner

end to 150 km at the outer mouth, covering an area of 17000

sq.km, of which only 2000 sq. km will be enclosed by

constructing a dam across the Gulf between Bhavnagar and

Dahej. For the construction of a dam, the design storm

estimates are required to compute the design flood.

Bhatt et.al. (2014) have generated Intensity duration

frequency analysis for different return periods for Bhadar

Dam in Gujarat. Ramaswamy, c (1987) studied the

catastrophic floods in the Sabarmati, Mahi and contiguous

rivers in July 1924. In WMO No.1045 (2009), the method of

computation of design storm estimates are described in detail.

In this paper, the design estimates in the form of Probable

Maximum Precipitation (PMP) for Kalpasar project in the

Gulf of Khambhat covering the river basins of Sabarmati,

Mahi, Dhadhar and some of Saurashtra Region are computed

by following WMO criteria.

II. DATA USED

The daily rainfall data of about 200 stations in and around

these catchment areas for the available period from 1901 to

2012 have been used for the selection and analysis of heavy

rainstorm. The hourly rainfall data of 4 self-recording

raingauge stations have been used for the preparation of time

distribution curves. The dew point temperature data of 3

stations namely, Ahmedabad, Porbandar and Rajkot have

been used for the computation of Moisture Adjustment Factor

(MAF). Maximum persistent dew point temperature of these

stations have been taken from the IMD (2000) met

monograph on “Generalized maps of 1-day point maximum

persisting dew point temperature”.

III. METHODOLOGY

The design estimates are given in the form of Standard

Project Storm (SPS) and Probable Maximum Precipitation

(PMP) estimates for 1-day, 2-day and 3-Day duration and

temporal Distribution (TD) of 24 hr and 48 hr rainstorms.

Generally the term storm is used for rainstorm.

A. SPS and PMP

The SPS is defined as the historical rainstorm that is the

heaviest rainstorm so far on record that has actually occurred

over or near the basin under study. This storm can be

considered to be reasonably characteristic of the region in

which the basin is located. The PMP is defined as the greatest

depth of precipitation for a given duration meteorologically

possible for a design watershed or a given storm area at a

particular location at a particular time of year, with no

allowance made for long-term climatic trends (WMO, 2009).

Few heaviest rainstorms over or near the study area

have been selected and processed for SPS estimation which

involves computation of Depth Area Duration (DAD), Depth


(IJSRD/Vol. 5/Issue 02/2017/026)


Duration (DD), transposed depths, temporal and areal

distributions. These are used for the evaluation of SPS. The

Moisture Adjustment Factor (MAF) is applied to SPS for

estimation of PMP. MAF is the ratio of highest liquid water

content recorded during rainstorm season near the centre of

rainstorm to the persistent liquid water content recorded

during rainstorm period. Liquid water content is estimated

from surface dew point temperature at 1000 hPa assuming

that environment is fully saturated and follows pseudo-

adiabatic lapse rate.

PMP = MAF * SPS

B. Temporal Distribution of Storm Rainfall

The spatial distribution of storm rainfall provides an idea

about volume of water precipitated during a rainstorm. The

temporal distribution of storm rainfall highlights intensity of

rainfall experienced during different times of rainstorm

duration. The highest intensity of rainfall decides the time of

occurrence of peak flood, magnitude of peak discharge and

consequently water level rising in river or stream.

The temporal distribution is computed from hourly

rainfall data of self-recording raingauge stations in and

around the catchment. The rainstorms are selected for

different duration i.e. 24-hours and 48-hours. From these

rainstorms highest rainfall recorded during intermediate

duration like continuous 3hr. .., 6hr..........., 24hr............., and

48hr duration are worked out. These rain depths are expressed

as percentage of total rainfall occurred during the storm and

plotted against the respective duration. The percentage

values are suitably filled with smooth curve in each case.

From these curves average temporal distribution is

derived. Such analysis is done for each selected rainstorm for

every SRRG station available in and around the catchment.

IV. RESULTS AND DISCUSSIONS

Fig. 1: Location and catchment area of Kalpasar Project.

The catchment area for the Kalpasar project in the Gulf

of Khambhat covering the river basins of Sabarmati, Mahi,

Dhadhar and some of Saurashtra Region is shown in Figure

1.

It also indicates the location of Kalpasar lake and the

system boundary of the river catchments. The design storm

estimates are given in form of SPS, PMP and Temporal

distribution. The SPS and PMP values are given for the area

of System Boundary covering areas of Sabarmati, Mahi,

Dhadhar, for entire catchment areas of Sabarmati, Mahi,

Dhadhar and some of river basins in Saurashtra region. The

rainfall contributions of SPS are also given sub-catchments

wise for the river basins within System Boundary and for the

Entire catchment.

The rainstorms of 1, 2 and 3-days are selected using

the historical daily rainfall data from 1901 to 2012. The

stations reported highest ever recorded rainfall (≥ 200 mm) is

given in the Table 1. The following severe most rainstorms

were considered for carrying out further analysis.

1) 26-28July 1927 (centre at Dakor)

2) 20-22June 1983 (Centre at Upleta)

3) 23- 25July 1905 (Centre at Radhanpur)

S.No. Catchment District Station Lat. Long. Data Period (years) Rainfall (mm) Date

1 Mahi Banswara Banswara 23.55 74.45 110 559 23/07/1959

2 Mahi Dungarpur Pderdi 23.75 74.12 27 512 26/08/1987

3 Mahi Banswara Garhi 23.60 74.13 99 490 9/7/2007

4 Mahi Dungarpur Dungarpur 23.85 73.72 108 486 30/06/1937

5 Mahi Panch-Mahals Halol 22.50 73.48 98 485 24/09/1945

6 Mahi Dohad Santrampur 23.18 73.87 65 465 29/07/1950

7 Mahi Baroda Baroda 22.33 73.27 83 460 24/09/1945

8 Mahi Anand Bhadran 22.37 72.90 53 451 23/09/1945

9 Mahi Panch-Mahals Kalol 22.62 73.47 100 440 24/08/1990




10 Mahi Banswara Khandu 23.45 74.53 71 419 30/06/1937

11 Mahi Banswara Khushalgarh 23.20 74.45 109 409 26/07/1913

12 Mahi Panch-Mahals Godhra 22.78 73.62 99 401 26/07/1927

13 Mahi Panch-Mahals Sangtala 22.57 73.92 23 400 23/08/1990

14 Mahi Broach Amod 22.00 72.87 99 395 5/8/1942

15 Mahi Anand Borsad 22.43 72.90 100 388 24/09/1945

16 Mahi Banswara Danpur 23.52 74.72 77 388 9/7/2007

17 Mahi Dungarpur Sagwara 23.68 74.03 100 384 26/08/1987

18 Mahi Dhar Badnawar 23.02 75.23 72 377 28/07/1996

19 Mahi Dohad Jhalod 23.09 74.15 99 368 27/07/1951

20 Mahi Banswara Arthuna 23.50 74.08 82 363 26/08/1987

21 Mahi Anand Cambay 22.32 72.62 91 354 24/09/1945

22 Sabarmati Kaira/Kheda Dakor 22.75 73.15 75 767 17/08/1982

23 Sabarmati Sabarkantha Malpur 23.35 73.47 42 475 28/07/1997

24 Sabarmati Sabarkantha Idar 23.85 73.00 88 463 13/08/1941

25 Sabarmati Kaira/Kheda Mehmedabad 22.83 72.75 100 446 13/07/1941

26 Sabarmati Sabarkantha Meghraj 23.50 73.50 45 445 18/07/1961

27 Sabarmati Kaira/Kheda Pinglaj 22.75 72.58 59 425 24/08/1990

28 Sabarmati Ahmedabad Ahmedabad 23.03 72.62 109 415 27/07/1927

29 Sabarmati Kaira/Kheda Kaira/Kheda 22.75 72.70 90 400 13/07/1941

30 Sabarmati Sabarkantha Modasa 23.45 73.28 98 387 18/07/1937

31 Sabarmati Sabarkantha Prantij 23.43 72.87 98 385 18/09/1950

32 Sabarmati Sabarkantha Byad 23.22 73.23 99 380 1/8/1997

33 Sabarmati Ahmedabad Dholka 22.72 72.45 99 377 6/9/1970

34 Sabarmati Sabarkantha Khedbrahma 24.38 73.05 35 376 1/9/1973

35 Sabarmati Ahmedabad Dehgaon 23.17 72.82 40 360 24/08/1990

36 Sabarmati Ahmedabad Aslali 22.92 72.58 48 351 13/07/1941

37 Saurashtra Ahmedabad Barwala 22.10 71.92 21 177 14/07/1998

38 Saurashtra Ahmedabad Dhandhuka 22.37 71.98 99 679 6/6/1976

39 Saurashtra Ahmedabad Dholera 22.25 72.18 81 448 6/6/1976

40 Saurashtra Ahmedabad Ranpur 22.35 71.72 85 276 11/7/1943

41 Saurashtra Bhaunagar Sihor 21.70 71.95 42 218 4/6/1976

42 Saurashtra Bhaunagar Songadh 21.73 71.88 67 232 18/04/1947

43 Saurashtra Bhaunagar Umrala 21.85 71.80 41 193 4/6/1976

44 Saurashtra Bhaunagar Vallabhipur 21.83 71.92 42 227 6/8/1968

45 Saurashtra Surendranagar Chuda 22.48 71.68 86 271 24/07/1905

46 Saurashtra Surendranagar Limbadi 22.57 71.80 31 301 7/9/1970

47 Saurashtra Surendranagar Surendranagar 22.70 71.67 24 198 18/08/1953

48 Saurashtra Surendranagar Wadhwan 22.70 71.67 96 316 7/9/1970

Table 1: Station wise highest recorded Rainfall (mm).

The above rainstorms have been subjected to

detailed isohyetal analysis. The analysis revealed that

rainstorm of 26-28 July 1927 for Dhadhar, Mahi and

Sabarmati river basins and 20-22 June 1983 for Saurashtra

Region, are the severe most rainstorms in the vicinity of the

project catchment. The Standard Project Storm (SPS) values

were estimated from transposed Depth-Duration values

corresponding of the project area on each side. The Depth-

Duration values which are taken as SPS values for 1-day, 2-

day and 3-day duration in respect of Kalpasar Project are

given in Table 2.

Table 2: SPS values for Kalpasar Project

The transposed isohyetal patterns for 1-day, 2-day

and 3-day duration over Saurashtra region are given in Fig. 2

to Fig. 4.




Fig. 2: 1-day transposed isohyetal pattern over Saurashtra

region.


region.


region.


and 3-day duration over System Boundary region are given

in Fig. 5 to Fig. 7.

Fig. 5: 1-day transposed isohyetal pattern over System

Boundary region.


Boundary region.


Boundary region


and 3-day duration over Entire Mahi, Sabarmati and Dhadhar

are given in Fig. 8 to Fig. 10.

Fig. 8: 1-day transposed isohyetal pattern over Entire Mahi,

Sabarmati and Dhadhar

Fig. 9: 2-day transposed isohyetal pattern over Entire Mahi,

Sabarmati and Dhadhar




Fig. 10: 3-day transposed isohyetal pattern over Entire

Mahi, Sabarmati and Dhadhar

The rainfall contributions of standard Project storm

for various durations in respect of sub-catchments area of

Dhadhar, Mahi and Sabarmati within System Boundary,

Entire area of sub-catchments Dhadhar, Mahi and Sabarmati

and some of sub-catchments of Saurashtra Region are given

in Table 3 and Table 4 respectively.

Table 3: Rainfall (SPS) contributions of Dhadhar, Mahi and

Sabarmati rivers within system boundary and for Entire River

catchments.

Table 4: Rainfall Contributions Sub-catchments of Saurashtra

Region within System Boundary

Also, the rainfall contributions in respect of five sub-

catchments while keeping the storm centre in upper Mahi and

Upper Sabarmati Portions have been computed and are given in

Table 5.

Table 5: When centre of storm placed on Upper Mahi

Portion and Upper Sabarmati Portion

A. Synoptic Situations

The Synoptic situations associated with historical rainstorm

of 26-28July 1927 and 20-22 June 1983 are described below.

1) Synoptic situations associated with historical rainstorm

of 26-28July 1927

The Severe rainstorm of 26-28 Jul 1927 was caused by a

monsoon depression which originated in the Bay of Bengal

on 23 July morning and traversed the Indian subcontinent.

The depression crossed the coast on 23 July and moved close

to Umaria in Uttar Pradesh on 25 July, Guna in Madhya

Pradesh on 26 July and Mount Abu in Rajasthan on 27 July.

From here, instead of moving in a westerly direction it turned

north and moved slowly for two days up to Jodhpur and then

dissipated some 500 km further north in the east Punjab hills.

The depression caused heavy rainfall along and near

its track during 26-28 July. On reaching Umaria, it stimulated

the activity of the Arabian Sea monsoon current bringing

moist south-westerly air flow over Gujarat and heavy rainfall

began in north Gujarat and south Aravali hills on the evening

of 25th July. The intensity of rainfall however increased when

the depression recurved and moved slowly northwards from

Mount Abu. The area under the rainstorm recorded 1-day

maximum rainfall on 28th July, 2-day maximum rainfall from

27-28 July and 3-day maximum rainfall from 26-28 July. The

centre of the rainstorm was located at Dakor (22.75° N,

73.15° E) in Gujarat, which recorded 540 mm, 997 mm and

1289 mm of rainfall in 1, 2 and 3-days respectively.

2) Synoptic situations associated with historical rainstorm

of 20-22 June 1983

The severe rainstorm of 20-22 June 1983 was caused a low

pressure area formed on 18th June over east central Arabian

Sea of north Maharashtra coast with associated cyclonic

circulation extending up to mid tropospheric level. It

extended up to south Gujarat coast on 19th June. The low

pressure area concentrated into a depression and lay centered

about 100 km south of Veraval on 19th June and about 50 km

south of Jamnagar in Gujarat on 21st June. The depression

was moved further and lay centred near Surendranagar in

Gujarat on the morning of 22nd June. The system weakened

by 23rd June morning into low pressure area. Under its

influence, the southern part of Saurashtra and Kutch received

heavy to very heavy concentrated rainfall during 20-22 June.

The area under the rainstorm recorded 1-day maximum

rainfall on 22nd June, 2-day maximum rainfall from 21-22

June and 3-day maximum rainfall from 20-22 June. The

centre of the rainstorm for 1-day, 2-day and 3-day durations

was located at Upleta (21.72° N, 70.30° E) in Gujarat, which

recorded 770 mm, 1067 mm and 1158 mm of rainfall

respectively. The rainstorm also recorded a 1-day maximum

rainfall of 394 mm on 20th June with the centre at Porbandar

(21.63° N, 69.60° E) in Gujarat.

B. Estimation of Moisture Adjustment Factor (MAF) and

Probable Maximum Precipitation (PMP)

It is expected that PMP would be a result of combination of

highest rain producing system in the atmosphere. It is

estimated that the highest rain producing efficiency is

experienced during occurrence of most severe rainstorm over

the basin. Hence SPS value is maximised by Moisture

Adjustment Factor (MAF) for evaluation of Probable

Maximum Precipitation.

The MAF for rainstorm of 26-28July 1927 is

computed on the basis of surface dew point temperature data

of Ahmadabad station and is of the order of 1.34. The MAF

for rainstorm of 20-22 June 1983 is computed on the basis of




surface dew point temperature data of Porbandar and Rajkot

stations and is of the order of 1.24. Corresponding PMP value

for 1-day 2-day 3-day duration for Kalpasar Project is given

in Table-6.

Table 6: PMP values for Kalpasar Project

It may be mentioned that for converting 1-day

design storm values into 24-hrs.value, clock-hour correction

factor is to be applied. This correction factor value is 1.15 in

the present case. Hence 1-day design storm values may be

increased by 1.15 times to evaluate corresponding 24-hr.

values.

C. Time Distribution Analysis

The average temporal distribution of 24-hour and 48-hour

storm rainfall is computed on the basis of SRRG data of

Ahmedabad and Ratlam for the river basins of Dhadhar, Mahi

and Sabarmati are given in Table-7 and Fig. 11. The average

temporal distribution of 24-hour and 48-hour storm rainfall is

computed on the basis of Rajkot and Bhavnagar stations are

given in Table 8 and Fig. 12.

Table 7: Temporal Distribution of Kalpasar Project for

within system boundary and for entire area of Dhadhar,

Mahi and Sabarmati rivers.

Fig. 11: 24hrs and 48 hrs Time Distribution curves for Mahi,

Sabarmati and Dhadhor rivers.

Fig. 12: 24hrs and 48hrs Time Distribution curves for

Saurashtra rivers

Duration

(Hours)

Temporal Distribution (%)

24-hour

storm rainfall

48-hour storm

rainfall

3 47 30

6 61 41

9 71 49

12 79 56

15 85 62

18 91 68

21 96 73

24 100 78

27 82

30 86

33 90

36 93

39 96

42 98

45 99

48 100

Table 8: Temporal Distribution of Design Storm of Kalpasar

Project for catchment area in Saurashtra region

These values are recommended as temporal

distribution of storm rainfall for converting PMP values into

flood hydrograph for Kalpasar Project.

V. CONCLUSIONS

Gujarat is a water deficit state specially, the Saurashra region.

To store surplus/untapped surface water, the Govt. of Gujarat

proposes Kalpasar project, an eligible option by construction

of a Gulf closure dam in Gulf of Khambhat, to store water

inflows of the rivers from both the sides, one from Dhadhar,

Mahi, Sabarmati and other from the Saurashtra rivers. The

rainfall analysis revealed that rainstorm of 26-28 July 1927

for Dhadhar, Mahi and Sabarmati river basin and 20-22June

1983 for Saurashtra Region is the severe most rainstorms in

the vicinity of the project catchment. The MAF for rainstorm

of 26-28 July 1927 is computed on the basis of surface dew

point temperature data of Ahmadabad station and is of the

order of 1.34. The MAF for rainstorm of 20-22June 1983 is

computed on the basis of surface dew point temperature data

of Porbandar and Rajkot station and is of the order of 1.24.

PMP values for 1-day, 2-day and 3-day for Dhadhar, Mahi

and Sabarmati rivers within System Boundary are 31.7, 57.5

and 80.8 cm and for the Entire catchment area of Dhadhar,

24-hour storm

rainfall

48-hour storm

rainfall

3 35 29

6 53 38

9 65 45

12 75 51

15 83 56

18 90 61

21 95 66

24 100 70

27 74

30 78

33 82

36 86

39 90

42 94

45 98

48 100

Temporal Distribution (%)Duration

(Hours)




Mahi and Sabarmati rivers are 24.9, 49.0 and 63.9 cm

respectively. The PMP values for 1-day, 2-day and 3-day for

catchment area in Saurashtra region are 50.2, 80.8 and 100.6

cm respectively. These PMP values along with the time

distribution curves give the design storm estimates for

computation of design flood. This project will be the world’s

largest man made fresh water reservoir in the sea and will

serve as a life line of the Saurashtra region as well as an

accelerator for the growing economic activities

of Gujarat State.

REFERENCES

[1] Bhatt, Jahnvi P., Gandhi, H. M. and Gohil, K. B.,

‘Generation of Intensity Duration Frequency Curve

using Daily Rainfall Data for Different Return Period’.

Journal of International Academic Research for

Multidisciplinary, vol.2, 2014.

[2] IMD, “Generalized maps of 1-day point maximum

persisting dew point temperature”, Meteorological

Monograph, Hydrology No. 13/2000, 2000.

[3] Ramaswamy, C., “Meteorological Aspects of Severe

Floods in India, 1923-1979”. Met Monograph, India

Meteorological Department, New Delhi, 1987.

[4] World Meteorological Organization, “Manual for

estimation of probable maximum precipitation (PMP)”,

WMO-No. 1045, 2009.

pmp estimates for kalpasar project in gulf of khambhat (india)20 mahi banswara arthuna 23.50 74.08...

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