Mamallan reservoir: 30 percent work done but NOC pending

CHENNAI: The Water Resources Department (WRD) has commenced construction of the Mamallan drinking water reservoir without obtaining a No Objection Certificate (NOC) from the Fisheries Department, with the WRD seeking the mandatory clearance only after nearly 30 per cent of the project work has been completed.

In a letter dated July 21, 2026, the Executive Engineer of WRD's Araniyar Basin Division, Chepauk, sought an NOC from the Additional Director of Fisheries and Fishermen Welfare for the "Formation of a New Drinking Water Reservoir in Kovalam Sub-Basin" between the East Coast Road (ECR) and Old Mahabalipuram Road (OMR) in Chengalpattu district.

The Mamallan reservoir is being developed as Chennai's sixth drinking water reservoir in the Kovalam sub-basin.

The project covers around 5,161 acres and has an annual storage capacity of 2.25 TMC. Former Chief Minister MK Stalin laid the foundation in January 2026, and work has been ongoing for six months, reaching 30 per cent completion.

Environmentalists and social activists have raised concerns about the delayed move to seek NOC and questioned how construction was allowed without obtaining the clearance, as the project potentially impacts fishing resources and local livelihoods.

"The fact that the WRD has approached the Fisheries Department for an NOC only now is an example of how casually the government is handling an environmental project. More than 5,000 people from 13 villages, including Irular tribal communities and several other sections of people, are likely to lose their livelihoods because of this project," Environmental researcher and writer Nityanand Jayaraman told DT Next.

"Although the project has been under implementation for more than six months, the Fisheries department has not opened its mouth on the issue. The letter seeking the NOC was sent on July 21 and, so far, the department has not given any response," the writer added.

He said construction had already begun and ecological impacts had started to occur. "At this stage, even if the Fisheries department wants to act, it is not in a position to undo the damage that has already been caused," he said.

Advocate Vetriselvan of Poovulagin Nanbargal said prior clearances and NOCs from all departments concerned were essential for environmental projects.

"According to Supreme Court judgments, prior clearances and NOCs from all the departments concerned are essential for environmental projects. There cannot be a post-clearance approach for such projects," he said.

He said the WRD seeking the Fisheries Department's NOC only after the Mamallan project had commenced indicated that a proper scientific study may not have been conducted before the work was taken up.

"If the project site is an officially recognised wetland in Tamil Nadu, the Wetlands (Conservation and Management) Rules, 2017 require an expert committee to examine the project before permission is granted. Such an assessment should have been conducted before the project commenced," Vetriselvan said.

He, however, pointed out that several wetlands in Tamil Nadu have still not been formally notified as wetlands despite their ecological importance.