Table of Contents
Sabarmati
Hydrological Observation Stations Map
Geographical description of the basin along with a basin map, showing sites of CWC.
Description
The Sabarmati basin extends over states of Rajasthan and Gujarat having an area of 21,674 Sq.km with maximum length and width of 300 km and 150 km. It lies between 70°58’ to 73°51’ east longitudes and 22°15’ to 24°47’ north latitudes. The basin is bounded by Aravalli hills on the north and north-east, by Rann of Kutch on the west and by Gulf of Khambhat on the south. The basin is roughly triangular in shape with the Sabarmati River as the base and the source of the Vatrak River as the apex point. Sabarmati originates from Aravalli hills at an elevation of 762 m near village Tepur, in Udaipur district of Rajasthan. The total length of river from origin to outfall into the Arabian Sea is 371 km and its principal tributaries joining from left are the Wakal, the Hathmati and the Vatrak whereas the Sei joins the river from right. The major part of basin is covered with agriculture accounting to 74.68% of the total area. 4.19% of the total basin area is covered by water bodies. The basin spreads over 15 parliamentary constituencies (2009) comprising 13 of Gujarat and 2 of Rajasthan.
Salient Features of Sabarmati Basin | |
Basin Extent Longitude Latitude | 70° 58’ to 73° 51’ E 22° 15’ to 24° 47’ N |
Length of Sabarmati River (Km) | 371 (in India) |
Catchment Area (Sq.km.) | 21674 |
Average Water Resource Potential(MCM) | 3810 |
Utilizable Surface Water Resource(MCM) | 1900 |
Live Storage Capacity of Completed Projects (MCM) | 1567.0 |
Live Storage Capacity of Projects Under Construction (MCM) | 110.0 |
Total Live Storage Capacity of Projects (MCM) | 1677.0 |
No. of Hydrological Observation Stations (CWC) | 13 |
No. of Flood Forecasting Stations (CWC) | 2 |
River System
The Sabarmati River with its origin in Rajasthan flows generally in South – West direction. It enters the Gujarat State and passes through the plains and continues to flow in the same direction and joins the Gulf of Khambhat in the Arabian Sea.At the 51 km of its run, the river is joined by the Wakal on the left bank near village Ghanpankari. Flowing generally in the South – West direction at 67th km of its run, it receives the Sei on the right bank near Mhauri and then the Harnav on the left bank at about 103 km. From respective sources beyond this confluence, Sabarmati flows through the Dharoi gorge. Emerging from the gorge it passes through the plains and is joined on its left bank at about 170 km from its source by the Hathmati, which is its major tributary. Continuing to flow in South – West direction, the river passes through Ahmedabad and about 65 km down stream, another major tributary, Watrak joins its on the left bank, flowing for a further distance of 68 km, the river outfalls in the Gulf of Khambhat in Arabian Sea.
Description of Tributaries
Sei
This is a right bank tributary of Sabarmati River.It rises in the Aravalli hills in Rajasthan and flows in South – West direction for a total distance of 95 km before it joins on its right bank. It drains an area of 946 sq km.
Wakal
This is a Left bank tributary of Sabarmati River.It rises in the Aravalli hills in Rajasthan and flows in South – West direction for a total length of 88 km. It joins Sabarmati on its left bank. It drains an area of 1625 sq km. The Menas is its main tributary.
Harnav
This is a Left bank tributary of Sabarmati River It rises in the Northern portion of the Kulalia hills of Rajasthan ranges and flows in South – West direction for a total distance of 75 km. Harnav joins the left bank of Sabarmati. It drains an area of 972 sq km.
Hathmati
This is a Left bank tributary of Sabarmati River This is a Left bank tributary of Sabarmati River It rises in SouthWest foot hills of Rajasthan range in Gujarat State and flows in South West direction for a distance of 122 km to meet the Sabarmati on its left bank.This tributary drains an area of 1526 sq km.
Watrak
This is a Left bank tributary of Sabarmati River It rises in Panchara hills in Dungarpur district of Rajasthan and flows in Southwest direction for a distance of 248 km and joins Sabarmati on the left bank.Watrak and its tributaries drain an area of 8638 sq km. A line diagram of river system giving information of Sabarmati Basin & its tributaries and sub tributaries etc. indicating the location of major structures is enclosed.
Climatic Characteristics
The Sabarmati Basin experiences 3 marked seasons – summer (Mar-May), Monsoon (June-Sep) & winter (Oct-Feb). From the available data & record, the basin contains two climatic regions, the northern part of the basin comprises sub tropical wet climate (generally basin area occupied by Gujarat). The major part of basin comprises tropical wet climate causes mainly due to existence of Aravalli & the Western Ghats. The climate varies from arid in the Saurastra area to semi –arid in north Gujarat to humid in coastal areas TEMPERATURE IN ( °C ) CWC SITES Year 2008-09
Year 2008-09 | Jotasan | Kheroj | Derol Bridge | Ratanpur | Kheda |
---|---|---|---|---|---|
MAX MIN | MAX MIN | MAX MIN | MAX MIN | MAX MIN | |
MAX | 44° 23° | 45° 26° | 44° 24° | 44° 26° | 39° 25° |
MIN | 29° 4° | 29° 10° | 33° 8° | 32° 9° | 35° 16° |
Rainfall
Rainfall varies from a meager few mm in Saurastra to over 1000 mm in southern part.The average annual rainfall in the Sabarmati Basin is about 787.5 mm The South - West monsoon sets in by middle of June and withdraws by the first week of October. The rainfall is mainly influenced by the southwest monsoon.
Mean Annual Rainfall in mm Sabarmati Basin CWC Sites
Name of Site | Data utilised up to 2007-08(No.of years ) | Average Rainfall in mm | Average No. of rainy days | Rainfall Year 2008-09 | No of Rainy days in 2008-09 |
---|---|---|---|---|---|
Jotasan | 13 | 671 | 38 | 491.4 | 41 |
Kheroj | 20 | 717 | 43 | 461 | 37 |
Derol Bridge | 20 | 760 | 40 | 635 | 30 |
Watrak Dam | 22 | 857 | 39 | 494.9 | 41 |
Raskaweir | 23 | 666 | 35 | 472 | 29 |
Ratanpur | 17 | 832 | 39 | 1153.5 | 31 |
Kheda | 23 | 749 | 37 | 846.4 | 43 |
Wind
Average wind speed is the lowest in Udaipur and higher in Ahmedabad district. In general, wind speeds are taken to be moderate over most of the months.
Geology
Hydro geologically the river basin is categorised by two distinct units:
- Consolidated formation: This hydro geological unit is mainly dominated by basaltic lava flows associated with inter trappean, infratrappean and Archean rock formation represented by phyllites gneisses, quartzite & granites. Consolidated rocks mainly underlie north-eastern part of Gujarat
- Unconsolidated formation: Ground water occurs under water table and in confined condition in the bed of sand, kankar & gravel that constitutes the alluvial aquifers occurred as discontinuous beds of varying thickness in hard rocks- terrain in the north & north eastern part of basin. The valley-fills that are having good ground water potential are quite prominent and significant in the hard rock areas in Udaipur.
In the northern part of the basin, including areas in Rajasthan and those in Sabarkantha district the aquifers available are the highly jointed and fractured or extensively weathered rock zones. Wells tapping some thick rock-formations of this type yield as much as 1, 00,000 litres per hour though – 40,000 litres per hour would be more common. Such aquifer of moderate potential is available within 100-150 m below GL and even as closed as at 30-40 m depth if one was especially fortunate. The parts of the basin in Kheda and Surendranagar district have only limited ground water potentials comparable to that in northern parts of the basin and good confined aquifers are not available. The phreatic aquifers in the alluvial strata are only suited for shallow wells and low yields tube wells.
Status of Surface Water Development
Sabarmati basin is well-developed in water resources. Most of the project are medium and minor. Before plan period Meshwo canal and Kharicut canal system was developed. Sabarmati reservoir (Dharoi), Hathmati reservoir and Meshwo reservoir project are major projects completed during the plan period.
Urban Centres and Industries
Gandhinagar and Ahmedabad are the important urban centres in the basin. Ahmedabad is an industrial city situated on the banks of Sabarmati. Important industries are textiles, leather and leather goods, plastic, rubber goods, paper, newsprint, automobile, machine tools, drugs and pharmaceuticals etc.
Hydrologic Network
Hydrologic observation in the basin are carried out by the Central and State Governments. The Central Water Commission maintains 13 gauge-discharge site and at one station sediment is observed and at 2 stations water quality is monitored.In addition gauge-discharge data are available at 30 stations established by the State Governments. The Central Water Commission operates 2 flood forecasting stations in the basin.
Issues
The industrial city of Ahmedabad poses the danger of water pollution by industrial waste.