Overview On January 19, 2026 , the Chief Minister of Tamil Nadu, M.K. Stalin , laid the foundation stone for the Mamallan reservoir . This project is proposed as Chennai’s sixth drinking water source and the State’s first freshwater reservoir along the coast, located at Vada Nemmeli on East Coast Road. Key Developments Project Details Cost: The project is estimated to cost ₹342.60 crore . Location: Situated in the Kovalam basin, covering the land between Thiruvidanthai and Kokilamedu. Implementation: The Water Resources Department (WRD) will implement the project. Area: The reservoir will spread over 5,161.27 acres . Storage Capacity: It will have a storage capacity of 1.65 TMC (Thousand Million Cubic feet) . Annual Capacity: The reservoir is expected to have an annual storage capacity of 2.25 TMCFT when filled twice. Water Supply: It has the potential to supply 170 MLD (Million Litres per Day) to Chennai. Boundaries: The site is bound by ECR (East Coast Road) on one side and Rajiv Gandhi Salai on another. Historical Significance The Chief Minister highlighted the historical importance of the region, noting that the reservoir is named after Pallava ruler Narasimhavarman I , also known as Mamallan , who founded Mamallapuram. The Pallavas were renowned for their water management systems, having created approximately 39 tanks , including Uthiramerur and Thenneri , which are still in use. Project Benefits Water Storage: The structure will store surplus water from 69 upstream tanks in the Manamathy tank group. Bund: It will have a bund extending for about 34 km . Seawater Intrusion: It will help prevent seawater intrusion. Groundwater Recharge: It will recharge groundwater in neighboring localities, including Thiruvidanthai, Thiruporur, and Mamallapuram. Water Supply: It will provide drinking water to 13 lakh residents in fast-developing areas like Sholinganallur, Medavakkam, and Pallikaranai. Fishing Opportunities There is a plan to restore the 15-km long Buckingham canal between Thiruvidanthai and Mamallapuram across 311 acres as part of the project. This will improve the livelihood of fishermen dependent on brackish water fishing. Fishing licenses will also be issued to fishermen in neighboring localities. Government Initiatives The Chief Minister refuted claims that the DMK-led government had failed to construct storage structures, listing 43 dams built between 1967 and 2011 . He also outlined significant initiatives taken by the State government to strengthen water resources management. He noted that Chennai’s landscape has changed significantly over the past five years due to several schemes implemented under the ‘Dravidian model’ regime, with more projects awaiting inauguration. Expert Opinions J. Jayakanthan , WRD Secretary , mentioned that fishermen would have new fishing opportunities in the reservoir, which would store excess floodwater draining into the sea. The project is expected to be completed in two years . The desilting of the Buckingham canal is expected to improve brackish water flow and floodwater, enhancing tidal exchange between the Muttukadu and Kokilamedu estuaries and creating better fishing grounds. The feasibility of introducing boat rides in the canal will also be studied. Nearly 34 lakh cubic meters of silt are planned to be cleared from 69 tanks feeding the reservoir. The feasibility of creating more such reservoirs along the coastline will be examined. G. Ravikumar , Director, Centre for Water Resources, Anna University , and principal investigator of the project, stated that the Centre for Water Resources had prepared the feasibility report to assess the quantum of water to be obtained from upstream catchment areas for storage in the new reservoir. Anna University will act as the knowledge partner for the project execution, and the WRD has provided ₹2.93 crore to the Centre for its consultancy services. In a few years, the groundwater table would undergo changes in the areas filled with inactive salt pans. Additional Information Representatives of 15 non-governmental organizations were honored at the event with awards for best water conservation efforts. Deputy Chief Minister Udhayanidhi Stalin , Public Works Minister E.V. Velu , MSME Minister T.M. Anbarasan , Chief Secretary N. Muruganandam , elected representatives, and senior officials of the WRD and Chengalpattu district participated in the event. UPSC Relevance This project is relevant to GS3: Infrastructure , GS3: Environment and Ecology , and GS2: Government Policies . It highlights the government's efforts to address water scarcity and promote sustainable water management practices. The historical context of Pallava water management systems also connects to GS1: History and Culture .