Chandigarh, April 5
Taking a step further to save Sukhna Lake from silting, the Chandigarh administration has asked the Society for Promotion and Conservation of Environment (SPACE), a local NGO, to study the silting of water bodies constructed in the area since 1975.

SPACE earlier conducted a study on the impact of soil conservation measures in the catchments of Sukhna Lake on groundwater, soil and geology. SPACE is going to start work on the project from April 9 and the data collected by it would help in keeping a check on the silting of the lake, said Dr SS Grewal, president of NGO.

These water bodies helped in reducing the rate of soil erosion in the catchment area of Sukhna Lake substantially. The study conducted by the NGO showed that the erosion, which was 160 metric ton per hectare per year in 1988, had been brought down to only five metric ton per hectare per year due to the construction of silt detention dams.

The catchment area of Sukhna Lake was a thick forest, replete with flora and fauna around 40 years ago. In 1958, its water spread was 230 hectares and average depth around 4.69 metres, but due to heavy silting the depth got reduced to two metres in 2004. The artificial three-km rain-fed lake (1.52 km long and 1.49 km wide) had lost almost 60 per cent of its storage capacity within the first 10 years.

However, the lake, which was dying due to heavy inflow of silt, was saved by building and monitoring of 190 water bodies in its catchment area.

According to Dr Grewal, since 1975 the Chandigarh administration had constructed 190 water bodies in the catchments to keep a check on the land erosion and silting of Sukhna. These water bodies were meant to accumulate the water from catchments area before the same water is flowed in to Sukhna when the silt sets down in these water bodies.

During the last study the NGO discovered that 132 earthen dams were still intact while others had flattened bearing vagaries of weather or some other reasons. Since no detailed topographic survey of sites was carried out while planning and designing so data on storage capacity and submergence area was not available.

Moreover, no precise record of volumes of silt received, storage lost or silt removed during de-silting of the lake was available till now, said Dr Grewal.

Now, the NGO would asses the water holding capacity, and quantum of silt deposited in addition to the condition of these bodies. It would also be assessed that which water bodies needed de-silting so that these were not filled with soil to the brim and silt was not flowed towards Sukhna, said Dr Grewal.

Source: Arun Sharma Tribune News Service