CHENNAI: Restoration of Sembakkam lake, that began amidst enthusiastic welcome from residents and activists alike almost seven months ago, has now run into a roadblock. Conservationists are unable to desilt what with an estimated 22 million litres per day of sewage flowing into the water body.
With only a month or two left for the onset of monsoon, conservationists are looking to finish a large part of the work this month. However, sewage has slowed things down.
“With this volume of standing water (sewage), neither are we able to dredge nor desilt the lake,” said Jayshree Vencatesan, managing trustee, Care Earth. Care Earth Trust is the implementing agency for the restoration project along with The Nature Conservancy, which is the donor agency.
The project was taken up at an estimated cost of over Rs 75 lakhs and was slated for completion by December this year. However, with unabated sewage flowing into the lake, the organisations have spent around Rs 12 lakhs for the removal of water hyacinth alone which may not be sustainable in the long run. Water hyacinth reappears quickly, drawing strength from the sullage and sewage in the lake.
“The way forward is regulated draining of the lake to reduce the water level, dredge and then to bioremediate. Then, water that is coming in after this will be clean,” said Jayshree.
However, this proposal, that has been finalised after a study conducted by the Indian Institute of Technology- Madras and Care Earth themselves, has run into opposition from a section of the local residents. Residents believe that draining the water will not allow the groundwater table to be recharged this summer.
The substrate of the wetland is contaminated from years of sewage and sullage. Even even if groundwater is recharged at this point, it is only the muck that will be recharged. With the flood regulator already constructed, regulated draining is the only way forward, said conservationists.
Sewage from neighbouring Chitlapakkam, Tambaram and Pallavaram reaches the lake. Lack of an underground sewage system is a battle that residents in the neighbourhood came close to winning in 2009.
An order issued by Municipal Administration and Water Supply Department stated that underground sewage system was to be taken up for eight town panchayats- Perungudi, Thirumazhisai, Perungulathur, Pallikaranai, Peerkankaranai, Chitlapakkam, Sembakkam and Madambakkam at a total cost of Rs 310.23 crores. The project failed to take off.
An official from the Chitlapakkam panchayat said, “Here, in Chitlapakkam, we ran into several issues when the underground drainage project was proposed. Mainly, at that time, nobody wanted a sewage treatment plant coming up near their house or their shop.”