CHENNAI: As the government plans to build a new reservoir, sources at the Public Works Department (PWD) told Express that they have alternate measures to increase water supply, costing not more than Rs 200 crore.The PWD’s proposal is to build check dams-cum-barrages on the Palar Basin and deepen tanks in the city to increase water storage by about 1 TMC (Thousand Million Cubic Feet).
Reservoirs similar to Thervoy Kandigai dam, constructed in November 2019 to exclusively store the city’s drinking water, are being planned. Costing nearly Rs 600 crore, it has a capacity to store 0.5 TMC of water. Currently, Chennai’s water supply comes from four major reservoirs — Chembarambakkam, Red Hills, Poondi and Cholavaram. Together, their capacity is 11 TMC. PWD officials said that their project would increase storage but the clearance lies in the State government’s hands.
“A new reservoir will cost at least Rs 700 crore to Rs 800 crore. We have sent our proposal to construct check dams-cum barrages-on the Palar Basin,” said a senior PWD official. This will be similar to the Vayalur check dam constructed over 100 years ago in Tiruchy at a cost of Rs 32.5 crore. The dam was later urbanised (deepened and strengthened) by PWD to hold more water. According to officials, the check dam gets filled after 72 hours of rain.Similarly, capacity enhancement has been planned at the tanks in Sriperumbudur and Kollaivoyal.
“Currently the storage is only about 150 to 200 Mcft. If the tank is deepened and connected to the Chembarambakkam reservoir, the capacity can be enhanced to 5 TMC,” said the official.
Chennai receives 810 million litres of water per day for domestic use. However, the city requires 1,200 million litres of water per day. The Metro Water department is working to bridge this gap by drawing water from Veeranam tank and other sources apart from five reservoirs that supply water to the city. Chennai corporation has been devoid of regular water supply since the State undergoes alternative seasons of copious rains and drought. These measures would help quench their thirst by the onset of next summer.
Prohibitive cost
“A new reservoir will cost at least Rs 700 crore to Rs 800 crore. We have sent our proposal to construct check dams-cum-barrages on the Palar Basin,” said a senior PWD official. The PWD also proposes deepen tanks in the city to increase water storage by about 1 TMC