Water to be drawn from Retteri lake to augment supply in Chennai city.

In yet another move to decentralise water supply and create more sources, the Chennai Metropolitan Water Supply and Sewerage Board is constructing a plant at Kolathur to treat water drawn from Retteri lake.

The plant, with a capacity to treat about 10 million litres of water a day, is expected to be ready in about a month. After Porur lake, the water board is developing infrastructure to use water from Retteri lake to augment supply to the city.

Spread over 280 hectares of land, Retteri lake can store up to 133 million cubic feet of water. The project to tap the lake as another drinking water source was actively pursued after its use as an alternative source during the 2019 drought.

In yet another move to decentralise water supply and create more sources, the Chennai Metropolitan Water Supply and Sewerage Board is constructing a plant at Kolathur to treat water drawn from Retteri lake.

The plant, with a capacity to treat about 10 million litres of water a day, is expected to be ready in about a month. After Porur lake, the water board is developing infrastructure to use water from Retteri lake to augment supply to the city.

Spread over 280 hectares of land, Retteri lake can store up to 133 million cubic feet of water. The project to tap the lake as another drinking water source was actively pursued after its use as an alternative source during the 2019 drought.

Officials said water drawn from Retteri was supplied through lorries as part of the contingency plan in 2019.

The ₹22-crore project had been chalked out after analysing its potential as a drinking water source on the lines of Porur lake.

Infrastructure, including 1.8-km-long pipeline to transmit water from the lake to the plant, had been developed as part of the project. Officials said such decentralised water supply system would reduce pumping cost, electricity cost and loss of resources during transmission by 20%-30%. Moreover, it would help develop reliable sources for safe water supply. It would serve areas around Kolathur, Madhavaram and surrounding areas, the officials said.

The Water Resources Department had taken up eco-restoration efforts in Retteri a few years ago. It had led to plugging sewage outfalls in 2017. Periodical testing of water samples indicated that the water quality had improved. Constructed wetlands would be provided in the lakebed to treat sullage if needed, the officials said.

The officials said a proposal had been submitted to the State government to deepen and enhance the capacity of the Retteri lake, which had been converted into a drinking water source.

The improvements made to Korattur lake upstream had helped prevent flow of sewage into Retteri lake. More such waterbodies must be rejuvenated and tapped as drinking water sources to meet the growing needs of the city and prevent encroachments, the sources said.

THE HINDU