The structure in Thirukandalam across Kosasthalaiyar River will help store water, recharge table

A long-pending project to build a check dam in Thirukandalam across the Kosasthalaiyar River, may finally take shape next month.

The Water Resources Department (WRD) is all set to settle the bids for the nearly Rs. 33-crore project, and will start construction work in mid-July. Thirukandalam is in Tiruvallur district, 27 km from Chennai.

The check dam aims at storing nearly 200 cubic feet of water that usually drains into the sea, which in turn will help recharge the groundwater table in villages in and around Thirukandalam. The water crisis in the locality is currently so severe that farmers in around 10 villages — including Agaram, Arikambedu and Guruvayal — have shifted from paddy cultivation to horticulture, as the groundwater table has dipped to below 80 feet.

G. Durai, a resident of Alinzhivakkam said the Kosasthalaiyar River, still overflowed during the monsoon season. However, illegal sand mining around it and nearby waterbodies had led to depletion of the water table. “I now grow jasmine and rose plants in my fields,” he said.

The check dam, which will be built between Tamaraipakkam anicut and Cholavaram Lake, will store surplus water that is let into the river from Poondi reservoir and the anicut.

Normally, a check dam is around 1.5 metres high. However, this check dam will be constructed at a height of 5.5 metre, an official said.

“The Kosasthalaiyar River carries about 65,000 cubic feet per second of water, and is filled to its brim during the rainy season. We want to use the space available at the point where the river is at its widest — 175 metres — to store excess water. This will help us retain surface water up to 10 km on the river,” the official said.

Nearly 200 cubic feet of water, which is equal to the amount of drinking water supplied to the city for a week, will be stored.

Another benefit of the check dam would be the possibility of transferring water to Cholavaram Lake, if the city needs it, the official added. Officials hope this project will be completed soon as, with a water crisis looming, and other projects to store water stalled, the State needs it desperately.

Originally, this project was to be a storage structure to store Krishna water from Andhra Pradesh. However, following protests over land acquisition plans, it remained on paper for over two decades. Last year, to meet Chennai’s growing water demands, the State government revived the project, and to avoid land acquisition, changed its design to that of a check dam.

WRD officials said that apart from building the check dam, the project will also ensure that the river’s flood banks, eroded in some places due to rampant sand mining, will be raised to a height of 10 metres.

The project, funded by the National Bank for Agriculture and Rural Development, is expected to be completed in a year.

Keywords: check dam

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