Monday, November 29, 1999

Lakes Tansa & Vihar will not be desilted: too costly, not enough time before rains

News posted by

The Brihanmumbai Municipal Corporation (BMC) has expressed its inability to de-silt Tansa and Vihar this year. The BMC said with monsoon less than a month away it was technically not possible to desilt the lakes, the Tansa in particular, because of its huge area, in such a short time using conventional methods. An alternative, faster method would not be feasible as the cost would run prohibitively high.The urgent need to increase the storage capacity of four lakes supplying water to the city by de-siliting them was felt following the acute water shortage this summer.The BMC was to take up de-silting of Tansa and Vihar, two of the oldest lakes, on priority to increase their capacity before the onset of rains. The lakes, created in the late 19th century, have huge silt deposits that need to be removed.With a good and early monsoon expected this year, the BMC hasn't enough time to carry out the work. "Tansa is spread over 19 square kilometers and desilting the vast, saucer-shaped lake for the first time will be extremely challenging. The conventional method will take a long time. Sand dredging can be quicker but is very expensive. The cost can run up to Rs 500 crore. Either way, it cannot happen this year," said a senior official from the hydraulic engineering department.He agreed this season was ideal for de-silting as the lakes had the lowest water levels ahead of a predicted good monsoon, but the need was not realised in time. Because of last year's poor rainfall, the lakes are inching closer to their lowest drawable levels. Considering this, corporators including Shiv Sena corporator and standing committee chairman Rahul Shewale wanted the lakes to be deslilted. While the full supply level of Tansa is 128 metres, it can be increased by at least 9 metres by de-silting. This effectively increases lake capacity by 15 per cent, which is equivalent to a month's supply. The catchment area of Tansa is 40 square km and the lake gets full within 8-10 days of a good rainfall. It supplies 480 million litres to the city everyday. Vihar lake supplies about 120 MLD.The hydraulic engineering department says desilting can only be possible next year. "We will have to ensure that waters in the Tansa and Vihar are used up first next year by November end. The water level will have to be lower than the lowest drawable level. After that we will get nearly seven months for desilting work,' said the official.

News posted by

Click here to read more news from
Please follow our blogs



No comments:

Post a Comment