With moderate rain set to continue over the city, the shutters of the Chembarambakkam and Red Hills reservoirs were opened on Tuesday to let out surplus water.
This marked a rare instance: the floodgates of four reservoirs were opened in January.
The Water Resources Department (WRD) initially released 500 cusecs (cubic feet per second) of water from the Chembarambakkam and Red Hills reservoirs that have started receiving floodwater running off their catchment areas.
Inflow doubles
The discharge went up from the three reservoirs, including Poondi, by the evening as the inflow doubled due to heavy rain.
The Chembarambakkam reservoir recorded the highest rainfall of 12 cm until 4 p.m.
Those at Poondi and Red Hills received 4 cm and 5 cm respectively. The Cholavaram lake recorded 6 cm.
WRD officials said that the level in the Chembarambakkam lake had reached 23.37 ft against the full level of 24 ft. Nearly 3,200 cusecs was let into Adyar river.
“The four lakes, including Cholavaram, already have 94% of water against their capacity, and surplus water had to be let out... A flood warning has been issued in areas downstream of the lake and along the Adyar, including Kavanur, Kundrathur and Tiruneermalai. The Adyar may carry up to 6,000 cusecs. This is minimal, compared with its capacity,” said an official. The level had almost touched the full 21.2 ft at the Red Hills lake, and the inflow doubled to 3,082 cusecs by the evening. “We released 1,500 cusecs around 4 p.m. into the surplus course because the reservoir has 3,273 million cubic feet (mcft) against its capacity of 3,300 mcft. A flood warning was issued at Vadakarai, Puzhal, Kosapur and Manali,” the official said.
For the first time since 2011, the shutters of the Cholavaram lake were opened to release 350 cusecs as the level was just a foot short of the full level of 18.86 ft. The surplus water from this lake goes into the Kosasthalaiyar.
Officials said the floodgates of the Poondi reservoir had been opened for two days now as it got water from catchment areas upstream. About 2,970 cusecs was discharged into the Kosasthalaiyar, and the quantum was doubled at night owing to a heavy inflow.
The waterbody also received Krishna water from Andhra Pradesh. Besides the good monsoon rain, Krishna water was the major reason for the lakes to be full to the brim this year. They had a combined storage of 10,986 mcft, against the total 11,757 mcft, as on Tuesday. On the same day last year, they had just half the present storage, officials noted.
