High alert for residents along Adyar, Kosasthalaiyar rivers

Chennai: In the wake of heavy rain across the Chennai region, the Water Resources Department (WRD) has issued high alerts for residents along the Adyar and Kosasthalaiyar rivers, with significant increases in the release of surplus water from Chembarambakkam and Poondi reservoirs from Wednesday morning.

The precautionary measures, taken to ensure dam safety amid rising inflows, are expected to cause a rise in river levels and may impact low-lying areas downstream.

At the Chembarambakkam Lake in Kancheepuram, authorities stepped up surplus water release to 500 cubic feet per second (cusecs) from 10 am on Wednesday. The inflow, which stood at 2,170 cusecs as of 6 am, has sharply increased following continuous rainfall. The reservoir, with a full capacity of 24 feet and 3,645 million cubic feet (mcft), recorded a water level of 20.84 feet (2,815 mcft) on Wednesday, up from 18.52 feet last week.

The discharge, raised from an earlier precautionary release of 100 cusecs that began on October 21, is part of standard flood control protocol to maintain water levels within the safe limit of 21 feet. WRD officials have cautioned residents in Sirukalathur, Kavanur, Kundrathur, Thirumudivakkam, Vazhudiyampedu, and Thiruneermalai to remain vigilant and move to safer ground as the Adyar River level is expected to rise.

Simultaneously, the WRD has escalated its flood warning for villages along the Kosasthalaiyar River as Poondi Reservoir (Sathyamoorthy Sagar) prepares for a major increase in discharge. Starting at 10 am Wednesday, the outflow has been increased to 4,500 cusecs from the ongoing 2,000 cusecs released since October 17.

Poondi, one of Chennai’s key drinking water sources, has recorded a storage level of 2,536 mcft at a depth of 33.05 feet, against its full capacity of 3,231 mcft and 35 feet. The reservoir has seen a steady rise in inflow, currently at 2,910 cusecs, due to releases from Kesavaram Dam, Kandaleru Canal, and other catchment areas.

Villages along the Kosasthalaiyar, including Nambakkam, Thamaraipakkam, Thirukandalam, Athur, Pandikkavanur, Jagannathapuram, and several localities in Manali zone including Manali New Town and Sadayankuppam, have been placed on high alert. Officials have urged residents to evacuate to safer places as a precaution against possible flooding.

The WRD has also assured that precautionary releases have been made well in advance from Chennai’s key drinking water reservoirs – Chembarambakkam, Puzhal, and Poondi – to maintain sufficient buffer levels. “So, even during very heavy rainfall, the volume of surplus discharge will remain controlled, allowing floodwaters from the Adyar and Kosasthalaiyar rivers to safely reach the sea without posing major risk. There is no need for panic as all flood regulation measures are being strictly followed,” said the Chief Engineer, Chennai Region, in an official statement.

Authorities stated that both releases are being closely monitored, and coordination between district administrations, disaster management teams, and local bodies has been intensified to ensure public safety.