What is the Mamallan Reservoir project in Tamil Nadu and why is it opposed?

The site at Vada Nemmeli along the ECR where former CM MK Stalin laid the foundation of the Mamallan Reservoir project | Photo credit: M. Srinath

Story so far: The proposed Mamallan dam in Chengalpattu district is being touted as a solution to two problems facing the rapidly urbanizing southern part of the Chennai metropolitan area – drinking water scarcity and flooding. But the project is also being built in a landscape of marshes, salt pans, backwaters and wetlands that support fisheries and provide feeding and nesting sites for birds. This has raised concerns among fishing communities, residents and environmental groups about the potential impact on wetlands, fisheries and local hydrology.

The reservoir was designed by the Water Resources Department (WRD) in the Kovalam sub-catchment between Old Mahabalipuram Road (OMR) and East Coast Road (ECR), stretching across parts of Thiruporur and Thirukalukundram taluks. The project received Coastal Regulatory Zone (CRZ) clearance and construction formally began in January 2026 during the former DMK regime. The current coalition government led by TVK also supports the project.

Published – 30 Sep 2026 12:08 IST