Sewage Threat to Chennai's Chembarambakkam Reservoir Prompts WRD Action

The Water Resources Department (WRD) has formally requested local bodies and the Tamil Nadu Pollution Control Board (TNPCB) to take measures against sewage pollution in the catchment areas of the Chembarambakkam reservoir, a critical drinking water source for Chennai.

This action follows complaints from residents of rapidly developing areas along the Cooum River, who reported sewage inflows into the river and its channels. Many of these localities lack underground drainage infrastructure, leading to untreated sewage being released into the waterway.

Residents of Manavala Nagar in Tiruvallur district have long demanded protection for this stretch of the river, which is vital for irrigation and groundwater recharge. D. Anandhakrishnan, a resident, stated that sewage enters the river between the Putlur and Jamin Korattur checkdams through storm-water drains and other inlets. With the river largely dry during non-monsoon months, sewage discharge becomes more prominent, polluting groundwater and affecting nearly one lakh residents.

According to Anandhakrishnan, the contaminated water reaches the Chembarambakkam reservoir whenever water is diverted from the river through the Bangaru channel. This channel is also polluted by sewage from households along its banks and solid waste dumped in the area, visible from the Vellavedu Bridge.

The 8-km-long Bangaru channel branches from the Cooum and also carries floodwater from upstream tanks. Residents have submitted representations to the WRD and the Chief Minister's cell. While the department promised to store floodwater near the checkdams during the upcoming monsoon, residents stress that sewage pollution must be addressed urgently.

In response, the WRD recently inspected the Chembarambakkam reservoir's catchment areas. Officials stated that the department has written to TNPCB and block development officers to collect water samples and identify pollution sources. Additionally, local bodies have been instructed to ensure that treated wastewater from sewage treatment plants is discharged into waterways only after proper treatment.

The WRD has committed to coordinating with other government agencies to prevent sewage pollution in the reservoir's catchment area.