Fishers allege Mamallan reservoir plan ignores tidal inundation risks
Traditional fishers from villages along the Kovalam sub-basin on Monday urged the State government to abandon the proposed Mamallan reservoir project, alleging that it had
Traditional fishers from villages along the Kovalam sub-basin on Monday urged the State government to abandon the proposed Mamallan reservoir project, alleging that it had been designed without adequately accounting for tidal movements and storm surges from the Bay of Bengal. At a press conference organised by the Save Nemmeli Marshlands campaign, fishers, environmentalists, and conservationists said government-commissioned Integrated Coastal Zone Management Plan, funded by the World Bank, indicate that much of the proposed reservoir site on the ‘uppankazhi’ salt marsh would be inundated by 3.5 to 4.5 metres of seawater during severe storm surge conditions. They argued that the Water Resources Department’s (WRD) proposal and the technical assessment by the Indian Institute of Technology Madras (IIT-M), submitted in support of Coastal Regulation Zone (CRZ) clearance, had not adequately assessed this risk.
S. Mohana of Periya Nemmeli said families dependent on prawn fishing feared losing their livelihoods if the reservoir came up. “We depend on catching prawns in these backwaters. If the reservoir is built, our entire livelihood will be lost,” she said. She expressed concern that during heavy rain, strong tidal surges already push seawater into the backwaters, and a reservoir in the area could pose additional risks to nearby residents. “It is dangerous to build a reservoir near the sea. It is not the same as building one on a river. Our entire lives depend on the sea, we know it well. This should not be done,” she said.
R. Narayanan, a traditional fisherman from Kovalam, said local communities had witnessed seawater entering the marsh during spring tides and the monsoon for decades. He claimed the proposed bunds would not prevent seawater intrusion into the reservoir. The speakers said that while the IIT-M assessment examined freshwater inflows from the western catchment, it treated the sea only as an outlet for surplus floodwater. They said that the proposed outlets to discharge excess water into the Bay of Bengal could instead allow seawater to enter the reservoir during storm surges. K.V. Sudhakar, president of the Madras Naturalists' Society, said the wetland was an irreplaceable ecosystem supporting rich biodiversity throughout the year.
Bird surveys conducted in the Kelambakkam-Kovalam-Nemmeli landscape between 2022 and 2025 have recorded between 107 and 137 bird species annually. “Even during the dry season, the marshlands are vital for over 135 species which includes migratory species, endemic species, IUCN Red List species,” he said. The speakers further cautioned that converting the marsh into a reservoir would eliminate about 4,375 acres of natural flood storage, increasing the risk of flooding in nearby areas such as Thaiyur, Kelambakkam, Thiruvidanthai, Padur, Pattipulam, Saluvankuppam and Mamallapuram.
The BriefWire