Home / Environment / Wetland vs. Water: Chennai's Mamallan Reservoir Sparks Debate
Wetland vs. Water: Chennai's Mamallan Reservoir Sparks Debate
30 Sep
Summary
- Mamallan Reservoir aims to solve water shortage and flooding in southern Chennai.
- Project site is a vital wetland supporting fisheries and diverse bird species.
- Concerns over ecological impact, hydrology changes, and fisherfolk livelihoods persist.
Construction on the Mamallan Reservoir in Chengalpattu district, intended to alleviate water shortages and flooding in southern Chennai, began in January 2026 and is backed by the current government. The project spans over 1,770.5 hectares and is situated in a landscape of marshes, salt pans, and wetlands.
Proposed by the Water Resources Department, the reservoir aims to store water from a large catchment area, addressing Chennai's precarious water situation where demand exceeds supply. It is expected to provide up to 170 MLD for nine months annually, serving over 50,000 people.
Environmentalists and local communities are concerned that the reservoir will fundamentally alter the existing wetland hydrology. The site is a critical habitat for numerous bird species and supports local fisheries and salt pans, which could be adversely affected by the conversion to a freshwater storage.
Concerns also exist regarding the impact on coastal ecosystems and fisherfolk livelihoods due to potential changes in estuarine dynamics. The CRZ clearance mandates measures to protect ecological flow and monitor salinity to mitigate these risks. Construction work was temporarily halted in September 2026 for a design review.
