River Sabarmati originate from ranges of Arravalli and traverses a stretch of about 400 Km. Dharoi dam was constructed in 1973 at Dharoi located 85 Km. Upstream of Ahmedabad. It receives some pollution load at Gandhinagar and assimilate considerable pollution load at Ahmedabad. Owing to the construction of the Dam, Sabarmati Carries only Dry Weather Flow without any assimilative capacity and starts stinking right at the beginning of the city since major storm water outlets discharges Sewage and Industrial waste waters. In the light of spread of urban area and chances of contamination of the River it was decided to conduct survey covering maximum stretch under threat.
A total of 1033.17 ha was surveyed. This included a 10 km stretch of the river from the Sabarmati Railway Bridge at Dufnala up to one km downstream of Vasna Barrage. On the eastern side, the survey covered up to 100 m from the riverbank or up to the immediate major road (whichever was more). On the western side the survey extended up to Ashram Road.
Key Findings
The river runs a meandering course of about 9 kms from Subhash Bridge up to the Vasna Barrage through the city with an average width varying from 325 to 500 m.
On observing the alignment of the river, there are two meandering loops. Wherever the river has meandered or turned its course, the river gorge has widened due to scouring. This is evident at Gaikwad Haveli and at Wadaj.
The average reduced levels (RL) of the riverbed at Subhash bridge (extreme north of the City) and Vasna Barrage (extreme south of the City) are 39.2 m and 37.4 m respectively, the slope of the river is 1:5000. The height of the banks ranges from 4 to 9 mts.
A negative slope is observed from Sardar Bridge to Vasna Barrage.
The edge is not clearly defined by embankments or retaining walls at most places. The river edge gently slopes down to the riverbed at several places, which have vegetation and have been encroached by slum settlements.
The RL of the top gate of the Vasna Barrage is 41.756 m. Filling Vasna Barrage up to this level results in flooding of the nearby areas in monsoons.
