Chennai water experts question need for ₹4,800 crore Minjur desalination plant
Water resources experts have urged the Tamil Nadu government to reconsider its announcement of a new 400 million litres per day (mld) desalination plant at Minjur, saying the state should first focus on sustainable and integrated water management measures that could prove more cost-effective and environmentally friendly.
On Wednesday, Chief Minister C. Joseph Vijay announced the establishment of the desalination plant at an estimated cost of ₹4,800 crore. The facility is intended to cater to north Chennai, Avadi, Minjur, and the Ponneri belt. According to the announcement, the project will likely be executed by Chennai Metrowater at the premises of the existing 100 mld Minjur desalination plant.
The existing plant has been non-operational since November 2024. Work is currently underway to begin partial operations of the plant, though no clear timeline has been given for its full restoration.
B. Sakthivel, a hydrologist and team leader who prepared the Water Security Plan for Chennai, said the plan recommended a different approach. It proposed improving the storage capacity of water bodies in Chennai and neighbouring districts, merging large water bodies to form reservoirs, and recycling and reusing wastewater generated from Chennai and adjoining areas as part of an integrated water management strategy for the Chennai basin.
Sakthivel also suggested that projects could be developed to convert lands already acquired for the proposed Parandur airport into a reservoir. He said such sustainable measures could be implemented at a lower cost than establishing desalination plants, which are energy-intensive and involve significant capital expenditure.
Members of the Tamil Nadu Public Works Department Senior Engineers’ Association echoed similar views, stressing the need to increase the storage capacity of traditional water bodies in the Chennai Metropolitan Area. The association has prepared a list of 507 tanks in various taluks that could be rejuvenated and linked to the existing water distribution network, calling it an economically viable alternative to desalination.
K. Nagarajan, a former special engineer and association member, pointed out that desalination projects could have environmental impacts, including on marine life and coastal ecosystems. Measures to mitigate those impacts, he said, would add to the overall cost of the project.
Chennai has faced recurring water shortages, and successive governments have turned to desalination as a reliable source. The city currently has two operational desalination plants — one at Minjur and another at Nemmeli — with a combined capacity of around 200 mld. The new proposal would add another 400 mld, substantially increasing reliance on the technology.
Experts argue, however, that a more comprehensive water security plan could reduce the need for such expensive projects. Restoring tanks, reducing distribution losses, and implementing large-scale wastewater recycling are among the measures they say should be prioritised before expanding desalination capacity.
The Tamil Nadu government has not yet responded to the experts' suggestions. Neither the Chief Minister's office nor Chennai Metrowater has issued a statement regarding the feasibility review called for by the experts.
