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

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

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 fresh water reservoir in the sea and may be used for irrigation along the west coast of India, in the state of Gujarat. Gujarat and drinking water for Gujarat specially Saurashtra region. is a water deficit state specially the Saurashra region which is The Gulf of Khambhat extends from north to south rocky and barren. The annual per capita water availability is about 200 km and the width varies from 25 km at the inner 540 cubic meter in Saurashtra region which is much below end to 150 km at the outer mouth, covering an area of 17000 the minimum requirement of 1700 cubic meter. To store sq.km, of which only 2000 sq. km will be enclosed by surplus/untapped surface water, the Govt. of Gujarat proposes constructing a dam across the Gulf between Bhavnagar and construction of Kalpasar project in the Gulf of Khambhat Dahej. For the construction of a dam, the design storm which is an eligible option that can store fresh water of the estimates are required to compute the design flood. rivers of Dhadhar, Mahi, Sabarmati from one side and some Bhatt et.al. (2014) have generated Intensity duration of the Saurashtra rivers from the other side. This will be the frequency analysis for different return periods for Bhadar world’s largest man made fresh water reservoir in the sea. For Dam in Gujarat. Ramaswamy, c (1987) studied the construction of reservoir, the design storm estimates are catastrophic floods in the Sabarmati, Mahi and contiguous required for computation of design flood. In this paper, the rivers in July 1924. In WMO No.1045 (2009), the method of design storm estimates in the form of Probable Maximum computation of design storm estimates are described in detail. Precipitation (PMP) estimates have been computed for the In this paper, the design estimates in the form of Probable Kalpasar project in the Gulf of Khambhat. Maximum Precipitation (PMP) for Kalpasar project in the Key words: Gulf of Khambhat, Kalpasar, SPS, PMP Gulf of Khambhat covering the river basins of Sabarmati, Mahi, Dhadhar and some of Saurashtra Region are computed I. INTRODUCTION by following WMO criteria. Gujarat is the western-most state in India which occupies the northern extremity of the western sea-board of India. It lies II. DATA USED between latitude 20º07' and 24º43' N and longitude 68º10' and The daily rainfall data of about 200 stations in and around 74º29' E. The state is bounded by Pakistan in the north-west these catchment areas for the available period from 1901 to and the state of Rajasthan in north. To the east it borders 2012 have been used for the selection and analysis of heavy Madhya Pradesh, and Maharashtra. The Union Territories of rainstorm. The hourly rainfall data of 4 self-recording Daman, Diu, Dadra and Nagar Haveli lie to the south of raingauge stations have been used for the preparation of time Gujarat. It has 1600 km long coast line by the Arabian Sea distribution curves. The dew point temperature data of 3 forming the western and south-western boundary. Gujarat is stations namely, Ahmedabad, Porbandar and Rajkot have a water deficient State. The annual rainfall in the state varies been used for the computation of Moisture Adjustment Factor significantly. The mean annual rainfall ranges between 300 (MAF). Maximum persistent dew point temperature of these mm to 2800 mm. Normal rainfall of the state is 720.6 mm. stations have been taken from the IMD (2000) met The normal rainfall of Gujarat region is 1107mm and of monograph on “Generalized maps of 1-day point maximum Saurashtra and Kutch is 578mm. The state has 6.4 % of land persisting dew point temperature”. area of the country and 5% of the country's human population, but its surface water resource is only 2% of the country. The III. METHODOLOGY annual per capita water availability is 990 cubic meter in the The design estimates are given in the form of Standard State which is much below the minimum requirement of 1700 Project Storm (SPS) and Probable Maximum Precipitation cubic meter. However, even after (PMP) estimates for 1-day, 2-day and 3-Day duration and including Sardar Sarovar Project (SSP), only 20480 million temporal Distribution (TD) of 24 hr and 48 hr rainstorms. cubic meters (54%) is possible to store. There is no suitable Generally the term storm is used for rainstorm. site of land in the State available for the creation of river valley project to store surplus / untapped above 40% surface A. SPS and PMP water. In such a circumstance, the Govt. of Gujarat proposes The SPS is defined as the historical rainstorm that is the to create a reservoir by construction of a Gulf closure dam in heaviest rainstorm so far on record that has actually occurred Gulf of Khambhat which is an eligible option to store about over or near the basin under study. This storm can be 10,000 million cubic meter water inflows of the rivers considered to be reasonably characteristic of the region in ( Dhadhar, Mahi, Sabarmati and some of the Saurashtra), which the basin is located. The PMP is defined as the greatest which accounts for 25% of total surface water resources of depth of precipitation for a given duration meteorologically Gujarat. Creation of this fresh water reservoir does not possible for a design watershed or a given storm area at a involve any land acquisition or rehabilitation of people, and particular location at a particular time of year, with no will serve as a life line of the Saurashtra region as well as an allowance made for long-term climatic trends (WMO, 2009). accelerator for the growing economic activities Few heaviest rainstorms over or near the study area of Gujarat State. This will be the world’s largest man made have been selected and processed for SPS estimation which involves computation of Depth Area Duration (DAD), Depth

Duration (DD), transposed depths, temporal and areal IV. RESULTS AND DISCUSSIONS 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. Fig. 1: Location and catchment area of Kalpasar Project. The temporal distribution is computed from hourly The catchment area for the Kalpasar project in the Gulf rainfall data of self-recording raingauge stations in and of Khambhat covering the river basins of Sabarmati, Mahi, around the catchment. The rainstorms are selected for Dhadhar and some of Saurashtra Region is shown in Figure different duration i.e. 24-hours and 48-hours. From these 1. rainstorms highest rainfall recorded during intermediate It also indicates the location of Kalpasar lake and the duration like continuous 3hr. .., 6hr...... , 24hr...... , and system boundary of the river catchments. The design storm 48hr duration are worked out. These rain depths are expressed estimates are given in form of SPS, PMP and Temporal as percentage of total rainfall occurred during the storm and distribution. The SPS and PMP values are given for the area plotted against the respective duration. The percentage of System Boundary covering areas of Sabarmati, Mahi, values are suitably filled with smooth curve in each case. Dhadhar, for entire catchment areas of Sabarmati, Mahi, From these curves average temporal distribution is Dhadhar and some of river basins in Saurashtra region. The derived. Such analysis is done for each selected rainstorm for rainfall contributions of SPS are also given sub-catchments every SRRG station available in and around the catchment. 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- Table 2: SPS values for Kalpasar Project Duration values which are taken as SPS values for 1-day, 2- The transposed isohyetal patterns for 1-day, 2-day day and 3-day duration in respect of Kalpasar Project are and 3-day duration over Saurashtra region are given in Fig. 2 given in Table 2. to Fig. 4.

Fig. 2: 1-day transposed isohyetal pattern over Saurashtra Fig. 6: 2-day transposed isohyetal pattern over System region. Boundary region.

Fig. 7: 3-day transposed isohyetal pattern over System Fig. 3: 2-day transposed isohyetal pattern over Saurashtra Boundary region region. The transposed isohyetal patterns for 1-day, 2-day and 3-day duration over Entire Mahi, Sabarmati and Dhadhar are given in Fig. 8 to Fig. 10.

Fig. 4: 3-day transposed isohyetal pattern over Saurashtra region. The transposed isohyetal patterns for 1-day, 2-day and 3-day duration over System Boundary region are given Fig. 8: 1-day transposed isohyetal pattern over Entire Mahi, in Fig. 5 to Fig. 7. Sabarmati and Dhadhar

Fig. 5: 1-day transposed isohyetal pattern over System Fig. 9: 2-day transposed isohyetal pattern over Entire Mahi, Boundary region. Sabarmati and Dhadhar

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 Fig. 10: 3-day transposed isohyetal pattern over Entire the activity of the Arabian Sea monsoon current bringing Mahi, Sabarmati and Dhadhar moist south-westerly air flow over Gujarat and heavy rainfall The rainfall contributions of standard Project storm began in north Gujarat and south Aravali hills on the evening for various durations in respect of sub-catchments area of of 25th July. The intensity of rainfall however increased when Dhadhar, Mahi and Sabarmati within System Boundary, the depression recurved and moved slowly northwards from Entire area of sub-catchments Dhadhar, Mahi and Sabarmati Mount Abu. The area under the rainstorm recorded 1-day and some of sub-catchments of Saurashtra Region are given maximum rainfall on 28th July, 2-day maximum rainfall from in Table 3 and Table 4 respectively. 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 Table 3: Rainfall (SPS) contributions of Dhadhar, Mahi and Sea of north Maharashtra coast with associated cyclonic Sabarmati rivers within system boundary and for Entire River circulation extending up to mid tropospheric level. It catchments. 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 Table 4: Rainfall Contributions Sub-catchments of Saurashtra June and 3-day maximum rainfall from 20-22 June. The Region within System Boundary centre of the rainstorm for 1-day, 2-day and 3-day durations Also, the rainfall contributions in respect of five sub- was located at Upleta (21.72° N, 70.30° E) in Gujarat, which catchments while keeping the storm centre in upper Mahi and recorded 770 mm, 1067 mm and 1158 mm of rainfall Upper Sabarmati Portions have been computed and are given in respectively. The rainstorm also recorded a 1-day maximum Table 5. 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 Table 5: When centre of storm placed on Upper Mahi experienced during occurrence of most severe rainstorm over Portion and Upper Sabarmati Portion the basin. Hence SPS value is maximised by Moisture Adjustment Factor (MAF) for evaluation of Probable A. Synoptic Situations Maximum Precipitation. The Synoptic situations associated with historical rainstorm The MAF for rainstorm of 26-28July 1927 is of 26-28July 1927 and 20-22 June 1983 are described below. 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

All rights reserved by www.ijsrd.com 98 PMP Estimates for Kalpasar Project in Gulf of Khambhat (India) (IJSRD/Vol. 5/Issue 02/2017/026) surface dew point temperature data of Porbandar and Rajkot Fig. 11: 24hrs and 48 hrs Time Distribution curves for Mahi, stations and is of the order of 1.24. Corresponding PMP value Sabarmati and Dhadhor rivers. 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. Fig. 12: 24hrs and 48hrs Time Distribution curves for values. Saurashtra rivers C. Time Distribution Analysis Temporal Distribution (%) Duration 24-hour 48-hour storm The average temporal distribution of 24-hour and 48-hour (Hours) storm rainfall is computed on the basis of SRRG data of storm rainfall rainfall Ahmedabad and Ratlam for the river basins of Dhadhar, Mahi 3 47 30 and Sabarmati are given in Table-7 and Fig. 11. The average 6 61 41 temporal distribution of 24-hour and 48-hour storm rainfall is 9 71 49 computed on the basis of Rajkot and Bhavnagar stations are 12 79 56 given in Table 8 and Fig. 12. 15 85 62 Duration Temporal Distribution (%) 18 91 68 (Hours) 21 96 73 24-hour storm 48-hour storm 24 100 78 rainfall rainfall 27 82 3 35 29 30 86 6 53 38 9 65 45 33 90 12 75 51 36 93 15 83 56 39 96 18 90 61 42 98 21 95 66 45 99 24 100 70 48 100 27 74 Table 8: Temporal Distribution of Design Storm of Kalpasar 30 78 Project for catchment area in Saurashtra region 33 82 These values are recommended as temporal 36 86 distribution of storm rainfall for converting PMP values into 39 90 flood hydrograph for Kalpasar Project. 42 94 45 98 V. CONCLUSIONS 48 100 Gujarat is a water deficit state specially, the Saurashra region. Table 7: Temporal Distribution of Kalpasar Project for To store surplus/untapped surface water, the Govt. of Gujarat within system boundary and for entire area of Dhadhar, proposes Kalpasar project, an eligible option by construction Mahi and Sabarmati rivers. 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,

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.