Two check dams that remain dilapidated to get new lease of life

It is expected to boost the groundwater level in the region

Two check dams across the Kosasthalaiyar river that remain dilapidated for nearly three decades are likely to get a new lease of life. The Water Resources Department (WRD) has proposed to reconstruct the storage structures located downstream of the Poondi reservoir and tap them as sources for Chennai’s water supply.

The damaged check dams at Velliyur and Gerugampoondi that are located 15 km and 20 km downstream of the Poondi have a groundwater potential to augment irrigation needs in 20 villages, including Punnapakkam, Eraiyur and Meyyur and recharge the well fields owned by the Chennai Metropolitan Water Supply and Sewerage Board (CMWSSB).

The department has sought World Bank funding for the project under the results component of Chennai Partnership programme. Officials of the WRD said the city could be supplied with about 180 million litres a day of drinking water through the well fields as the pipeline network already existed. Groundwater could be used to provide drinking water to the surrounding localities.

Citing a United Nations Development Programme study carried out during the 1960s, the officials said the well fields, including in Tamaraipakkam, Poondi and Kannigaiper, were formed to tap the rich groundwater source.

However, the check dams constructed by Tamil Nadu Water Supply and Drainage Board were damaged then. The new check dams, which would be 300 metres wide and of nearly 1.75 metres height, would help conserve floodwater that otherwise drains into the sea, manage drought and mitigate the problem of flooding. Both the storage structures would have a capacity to store about 50 million cubic feet of water.

The feasibility of developing them as riverine reservoirs and providing shutters is being explored. This would enable storing of surface water for nearly 5 km upstream. Moreover, recharge shafts would be sunk on the rivered to allow groundwater percolation.

Besides boosting the water table and enhancing the livelihood opportunities of agricultural and fishing communities, the new check dams would minimise the threat of illegal sand mining.