The shutters of the Poondi reservoir were opened on Monday evening, much ahead of Northeast monsoon, which provides major share of rains. The water released from the reservoir is being be diverted to Cholavaram reservoir.
Following heavy rains in catchment areas of the Kosasthalaiyar in this southwest monsoon, the Water Resources Department (WRD) decided to release 1,000 cusecs of water from two flood gates of Poondi reservoir around 4 p.m. on Monday. The water level has touched 33.90 feet, just one feet lower than its maximum level as the reservoir received good inflow of about 1,520 cusecs around 6 a.m.
Water discharge from city reservoirs is more common during the northeast monsoon. Spread over 34.58 sq.km. in Tiruvallur district, the reservoir, which is one of the prime waterbodies used as Chennai’s drinking water sources, has a storage of 2.79 tmcft. as against its capacity of 3.23 tmcft.
Flood alert
Tiruvallur district administration has issued a flood warning to people living in low level areas along the Kosasthalaiyar such as Krishnapuram, Beemanthoppu, Tamaraipakkam, Pudukuppam, Napalayam, Idayanchavadi, Manali, Sadayankuppam and Ennore.
Officials said the water discharged from Poondi reservoir into the Kosasthalaiyar would not be drained into the sea. It would be instead used to fill the Cholavaram reservoir, which has only minimum storage. Water would be diverted from Tamaraipakkam anicut through a 13-km upper supply channel to Cholavaram.
Moreover, water discharged would be used to recharge checkdams located downstream of Poondi and across the Kosasthalaiyar. “This will help maintain the river regime-the annual variation in amount of water during different seasons. Discharge of water will help smooth flow during heavy floods in future,” said an official.
The reservoir is expected to receive more inflow. Tiruttani, which is part of the catchment area of the Poondi reservoir, recorded 13 cm rain on Saturday. A minimum discharge would be maintained even after drop in inflow, the official added.
The department has sought a decrease in the Krishna water supply from Andhra Pradesh. On Monday, Poondi reservoir received nearly 370 cusecs of Krishna water apart from floodwater. Since July 1, Chennai has realised nearly 2 tmcft of Krishna water.
Noting that Chembarambakkam reservoir’s shutter gates were opened in June last year because of unusual rains, the officials said the water level is being monitored in other lakes too. The five waterbodies used for city water supply have a total storage of nearly 70% of their capacity.
Chennai would not face any water crisis for another year as there are enough resources for daily water supply, the officials added.
