To infuse life into polluted lakes around the city, the Water Resources Department (WRD) has recently submitted a proposal to the Ministry of Environment and Forests to restore these water bodies under the National Lake Conservation Plan (NLCP).
The NLCP’s objective is to rejuvenate urban and semi-urban lakes that have been polluted by the release of sewage into them.
Kolavai lake in Chengalpattu, about 50 km from the city and a popular tourist destination, has been chosen for the project. The lake has been contaminated thanks to sewage from the town released into it, leading to its degradation.
The WRD has decided to conserve such degrading water bodies in order to supply water from them to industries, instead of depending upon city reservoirs like Poondi and Chembarampakkam.
According to WRD sources, at present, five million gallons of water (equal to nearly 227 lakh litres a day) are drawn from the lake daily, and treated to be used at the Mahindra World City industrial park.
“We could use water from reservoirs to take care of drinking water and can tap water from tanks that are no longer used for irrigation, to provide water to industries,” said an official.
Kolavai lake, spread across 802 hectares, has the capacity to hold nearly 476 million cubic feet of water. It is fed by nearly 25 tanks located upstream in places such as Paranur, Hanumanthapuram and Kunnavakkam, and has a catchment area spread over 53 sq. km.
Once it is restored and adequate infrastructure provided for sewage treatment under the NLCP, the lake could then be used to draw nearly 10 million gallons of water per day (MGD) for industrial supply.
As the lake is located in a rocky region, the ground water recharge is not much. This makes it essential to restore the lake to sustain water quality in the surrounding villages.
There is also a proposal to improve the aesthetics of the lake through a public-private partnership initiative, and further encourage tourism. It may be recalled that the tourism department operated a boat club here until a few years ago. However, the water body is heavily silted now.
Chennai Metrowater officials recalled proposals devised a decade ago to convey water from the Kolavai lake to the city after treating it. There were plans to transmit the water through a 50-km pipeline to Porur lake to tackle a crisis then. For a brief period, water was drawn for industrial supply through tankers in 2001.
Discharge of raw sewage was found to be a problem then, and measures were taken to check it. However, the proposal was dropped later, they added.
Residents suggested that similar initiatives could be taken for lakes, which do not serve irrigation needs anymore, such as those in Velachery, Tirusulam and Chitlapakkam.
