The Tamil Nadu State Coastal Zone Management Authority submitted before the Southern Bench of the National Green Tribunal that the proposal was examined by the Chengalpattu District Coastal Zone Management Authority, the Technical Expert Committee, the State Expert Appraisal Committee, and IIT-Madras before the CRZ clearance was granted.
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The Tamil Nadu State Coastal Zone Management Authority (TNSCZMA) has defended the Coastal Regulation Zone (CRZ) clearance granted to the proposed Mamallan Reservoir project in Chengalpattu district before the Southern Bench of the National Green Tribunal.It argued that the project complies with the CRZ Notification, 2011, and was subjected to multiple levels of technical scrutiny. It also has stringent environmental safeguards.In its counter-affidavit, the authority sought the dismissal of a petition, filed by K. Saravanan, challenging the CRZ clearance issued in December 2025 for the proposed reservoir in the Kovalam sub-basin. The site falls between East Coast Road and Old Mahabalipuram Road.The counter-affidavit described the petition as “misconceived, speculative, and devoid of merits”.According to the authority, the proposed Phase-I reservoir will cover 1,770.5 hectares (4,375 acres) and have a storage capacity of 1.655 tmc ft to address drinking water shortage in the southern parts of the Chennai Metropolitan Area. It said the reservoir would cater to around 50,000 residents in areas including Nemmeli, Krishnankaranai, Pattipulam, Paiyanur, Kalavakkam, Thiruporur, Thiruvidanthai, and Mamallapuram, besides mitigating floods and seawater intrusion.The counter-affidavit said the proposal was examined by the Chengalpattu District Coastal Zone Management Authority, the Technical Expert Committee, the State Expert Appraisal Committee, IIT-Madras, and TNSCZMA before the CRZ clearance was granted.It argued that the project falls within the purview of activities permitted under the CRZ Notification, 2011, and subsequent clarifications issued by the Union Ministry of Environment, Forest and Climate Change for public utilities such as water supply, salinity prevention, and freshwater recharge.The authority contended that the project does not involve reclamation of the sea, estuary, or tidal waters, but is proposed entirely on inland floodplain poromboke land. Acknowledging that a large portion of the site is classified as Kazhuveli in revenue records, and is identified under the National Wetland Mission, the authority argued that the area had not been notified under the Wetlands (Conservation and Management) Rules, 2017.The counter-affidavit said the clearance was granted subject to several conditions, including maintaining ecological flows, undertaking biodiversity, hydrological and groundwater studies, preventing sewage and industrial effluent from entering the reservoir, monitoring salinity, protecting the Kovalam estuary, and submitting quarterly compliance reports through an independent environmental monitoring agency.The project has, however, drawn sustained opposition from fishing communities and environmental experts. Fisher representatives from villages along the Nemmeli-Kovalam backwaters have alleged that they were not consulted before the project was approved, and that the reservoir would affect the livelihoods of thousands of inland and marine fishers dependent on the brackish water ecosystem.They have also contended that converting the tidal marsh into a freshwater reservoir could increase flood risks to neighbouring villages and damage fisheries, mangroves, and the estuarine ecosystem. Published - July 06, 2026 09:23 pm IST
