Metrowater setting up treatment plants to decentralise supply network in Chennai

In an effort to strengthen water security and reduce dependence on distant sources, Chennai Metropolitan Water Supply and Sewerage Board is building a network of decentralised freshwater treatment plants that will source water from neighbourhood lakes, and supply to surrounding areas.

The Metrowater is constructing two new plants in Perumbakkam and Mogappair, each with a capacity to treat 10 million litres of water a day (mld) to augment water supply in the fast-growing city. At present, Chennai has a network of five treatment plants with smaller capacities. The upcoming ₹15.68-crore Perumbakkam plant would source water from Perumbakkam lake, while the Mogappair plant would draw water from Ayanambakkam lake, said officials.

Nearly 79% of the work to construct Mogappair treatment plant, coming up on a 3,150 sq.m. site, has been completed. The ₹13.01-crore project also includes laying a nearly 7.7 km pipeline to draw water from Ayanambakkam lake. The work is expected to be completed by March. Treated water from the plant would be conveyed to the distribution station in Anna Nagar west extension.

Spread over 85 hectares, the Ayanambakkam lake remains a key source of drinking water and groundwater recharge for neighbouring areas, including Koladi. It is among the water bodies identified for restoration by the Chennai Metropolitan Development Authority.

M.K. Jayakumar, a resident of Ayanambakkam, said groundwater is available at a depth of 30 feet in the area as the lake retains water for most months of the year. The Tiruverkadu municipality has also sunk borewells near the lake to supply drinking water.

With apartment complexes mushrooming, the water table is depleting. The lake and its supply channel must be rejuvenated and boating ride could be introduced, he said.

Officials said the decentralised water supply system would help rationalise water supply to meet the city’s growing needs. Such a system was essential to reduce pumping and electricity cost and cut transmission losses by 20%.

Five lakes in Porur, Retteri, Ayanambakkam, Perungudi, and Perumbakkam have been converted into drinking water sources. The water agency is studying the feasibility of tapping more water bodies to expand the decentralised supply network, officials said.