Located between Nemmeli and Kovalam in Chennai, the Great Salt Lake also known as Kovalam-Nemmeli backwaters, is a coastal wetland that spans 5,000 acres. The Tamil Nadu government plans to convert this coastal wetland into Chennai’s sixth drinking water reservoir: the Mamallan reservoir. The state government plans to convert this coastal wetland into Chennai’s sixth drinking water reservoir: the Mamallan reservoir. Construction activity at the Nemmeli coastal wetland has begun, with newly raised bunds and tracks. Coastal reservoir and groundwater rechargeFor a reservoir to recharge groundwater, its bed must be above the groundwater level to allow downward flow, and it must be sufficiently permeable.