CHENNAI: Portions of the Chembarambakkam reservoir’s bund wall have been razed by the Public Works Department (PWD) to clear the rampant weed growth in the lake. When the sluice gates of Chennai’s largest reservoir were opened recently after the lake got filled to the brim thanks to the good monsoon, a large mass of water weeds that carpeted the lake’s surface blocked the outflow.
In desperation, PWD officials had to break the bund wall in two places near the reservoir’s gates to deploy earth movers and fish out the weeds from the waterbody. The vegetation was so thick that conventional manual methods of weed-removal did not work.
Ramraj, a resident of Kundrathur, said the weed growth was unprecedented this year and authorities did not intervene even after the catchment areas began receiving heavy rains and filling up the lake. “The lake gets infested with weeds every year, and they usually get flushed out when the gates are opened. But this time, several hectares of the lake were infested with weeds. Some of them were deep-rooted, and required deployment of heavy machinery.”
Noted botanist D Narasimhan said visuals show Chembarambakkam lake is infested with different varieties of weeds. “We need to take a closer look as some of these varieties thrive in polluted water. Officials must regularly remove the invasive species, or they can affect the fish. Since Chembarambakkam lake is a major source of drinking water for Chennai, a thorough investigation must be conducted to find why such weeds are growing.”
A case is pending in the southern bench of the National Green Tribunal on the alleged pollution caused by manufacturing units at the nearby industrial estate. When contacted, senior officials of the Tamil Nadu Pollution Control Board and PWD said similar complaints of pollution were made in 2019 and the water quality was tested. “We did not find anything untoward in the test results. Industries at the nearby SIPCOT treat their sewage and effluents before releasing them into the lake. We will take action if violations are observed,” a TNPCB official said.
PWD authorities said the razed bund wall will be rebuilt within a month. “Only a small portion was removed,” they said.