Chennai’s Cholavaram Reservoir Almost Dry

This is a situation the city has been dreading all along. The Cholavaram reservoir, one of the four main sources of water for Chennai, is almost dry and the water level has hit dead storage. Fearing that whatever water left in the reservoir will be lost to evaporation, officials are using pumps to draw water and store it in the Red Hills reservoir, seven km away.

With the monsoon failing badly, water storage in the city’s reservoirs is almost half of what it was at the same time last year. The combined storage in the four reservoirs Poondi, Cholavaram, Red Hills and Chembarambakkam was 3.4tmcft (thousand million cubic feet) on Saturday which, officials said, may not last beyond first week of July. At the same time last year, the storage was 6.2tmcft. Chennai needs about 1 tmc ft of water every month.

“Judicious use of water is more crucial this year than ever before, because of breakdown in the supply chain of Krishna water and Veeranam supply being precarious,” said S Rangarajan, chairman, Neer Exnora.

Officials said Cholavaram had gone dry and the available water at the dead storage was being pumped out to Red Hills reservoir through a channel using two 60HP pumps. Usually, water flows our of the reservoir to Red Hills without the help of pumps, they said. “At least 15 cusecs (cubic per second) of water is released daily to the channel using pumps,” said a senior government official. He said all the remaining water in the reservoir could be pumped out in a month.

On Saturday, the storage at Cholavaram stood at 63mcft (million cubic feet), against the capacity of 881mcft. One cubic foot of water is equivalent of 28 litres. Officials said at least two to three mcft of water evaporates every day from the reservoir, and at this rate the storage may not even last a month.

“It is a repeat of 2004. A drying up Cholavaram gives a lot of room for rapid evaporation. Red Hills with a better storage will help control evapouration,” the official said.

Currently, 40 million litres of water is drawn from Metrowater’s wells in Neyveli, Poondi, Thamaraipakkam and Minjur to augment the supply from reservoirs. The wells were dug up way back in 2003-2004 when Tamil Nadu faced a severe drought and Chennai had rely on tanker supply from other parts of the state for its daily needs.

“Even the water tanker supply has been stepped up in tail-end areas. At least 370 tankers have been engaged under contract now,” government sources said. Metrowater is also evolving micro-plans to meet the impending crisis.