Major Chennai reservoirs have 40 per cent silt

Chennai: Environmentalists and urban planners admit that consecutive state governments failed in conserving rainwater. According to them, all four major reservoirs in Chennai, which brimmed early this week has silt for more than 40 per cent and have not been desilted since Kamaraj days dating back to 1960s.

A senior PWD insider admitted that all the major reservoirs and supporting sprawling lakes in Kancheepuram and Tiruvallur have silt that has accumulated for more than three decades.

For instance, the Madurantakam reservoir was desilted in 1969 during the prime ministership of Indira Gandhi. Of the total 2411 acres spread,  the reservoir over the years had been only partially desilted, once in three to five years, the source hinted.

Former Madurantakam legislator and Kancheepuram district farmers’ association president Ukkam Chand alleged that despite several representations, the district administration has failed to take up desilting works on large scale. During early 70’s, Madurantakam supported three-crops in Kancheepuram, but the current scenario is such that the reservoir fails to support even a single crop due to heavy silting.

The surplus water in Chembarambakkam and Madurantakam is drained.  In the case of Madurantakam lake, it is worse. The reservoir fills up with first few spells of rain due to 50 per cent unch ecked silt accumulation.

Even during July 2015, a memorandum was submitted to the Kancheepuram PWD authorities seeking desilting by dumping the removed silt in adjacent Karunkuzhi quarry, but it was not done, he added.

When contacted,  a PWD official said desilting the entire lake or any reservoir is practically not feasible for various reasons. The water body has to be completely dry and there has to be nearby vacant land to dump  the removed silt. Funding for massive desilting is a problem.  Red Hills, Chembarambakkam, Poondi and Madurantakam have been periodically desilted in a phased manner over the years.  

The concept of desilting and channelising storm water needs in depth planning and execution. The present regime failed to take adequate measures. As a result,  more water was released from Chembarambakkam flooding Saidapet and Kottur, alleged former mayor M. Subramanian.

“There is no second thought and the existing lakes have to be deepened like ponds to enhance catchment and recharge rain water. More thrust is required to conserve storm water as practised during Kamaraj days,” said environmentalist R Govindaraj of Exnora International.

Puzhal lake strong, water seepage under control
After reports of water seepage, Tiruvallur district collector Veera Raghava Rao on Thursday inspected Puzhal lake in Red Hills which is one of the four drinking water supplying reservoirs and said that the reservoir was stable and safe as the water seepage was under the permissible limit. Seepage of water from the reservoir has created a panic in Red Hlls with people gathering to see it. Inspecting the reservoir with PWD officials, Mr Rao told reporters that there was no danger to the public as the bund of the reservoir was stable and strong.

Reservoir update
Puzhal reservoir has a storage of 2,228 million cubic feet as against its total capacity of 3,300 mcft and receiving an inflow of 1,196 cubic feet per second.  Puzhal has lowest storage among the four reservoirs with 67.5 per cent of its capacity. Poondi (2755 mcft) and Chembarambakkam (3122 mcft) have stored water to over 85 per cent of its capacity while Choolavaram has 654 mcft of water or 74 per cent of its total capacity. Mr Rao said reservoirs are built with masonry structure allowing seepage to ensure stability of the bunds considering the potential energy of the water storage. "There is no need to panic as seepage in Puzhal reservoir is very strong. All the reservoirs including Poondi, Choolavaram and Chemberambakkam are safe and under close monitoring of PWD officials," he said.
 

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