WRD plans to restore, improve storage in six waterbodies at a cost of ₹298 cr.

Fall in demand for silt from waterbodies pushes WRD to alter rejuvenation proposals

Once the project is completed, the lakes will have an additional capacity to store a minimum of 2,800 mcft of water. Picture shows the Madurantakam lake in Chengalpattu district.

With market demand for silt from waterbodies becoming limited, the Water Resources Department is adopting a different approach to rejuvenate and create additional storage in lakes in the neighbouring districts. There are also plans to convey water for Chennai’s drinking water needs.

The Department has submitted a proposal to restore and improve storage of six waterbodies in Kancheepuram, Chengalpattu and Vellore districts, at an estimated cost of ₹298.38 crore. The aim is to address multiple issues, including the mismatch between the growing water demand and the availability of resources, increase in the number of intense rainfall days and seawater intrusion in coastal areas.

Less demand

Officials of the WRD said that it was found that sometimes desilting of lakes alone added only 10% to the storage capacity.

Moreover, there were limitations in transporting silt removed from lakes and less demand in the market. With the current demand, the storage capacity could only be increased by 700 million cubic feet (mcft).

Instead of just desilting the waterbodies, the Department plans to raise the height of the bund and weir — a structure that allows surplus water to flow out — by 3-5 ft.

This will boost the waterbodies’ storage capacity by 30-40% and save excess rainwater from draining into the sea, the officials said.

The Department plans to improve storage of large waterbodies in Madurantakam, Chengalpattu district; Uthiramerur, Thenneri in Kancheepuram district; Dusi-Mamandur in Tiruvannamalai district and Kaveripakkam and Mahendravadi in Vellore district. Most of these waterbodies have a capacity to store nearly 900-1,000 mcft each.

“Once the project is completed, the six waterbodies will have an additional capacity to store a minimum of 2,800 mcft of water,” said an official. For instance, the capacity of the Thenneri lake is expected to increase from the present 1,041 mcft to 1,997 mcft, after the project is completed.

As raising of the bund and the weir height may lead to inundation of land in the foreshore area of the waterbodies, the Department plans to fill land on the foreshore with silt, and raise their height as well. Once the State government gives its nod for the project, it will be completed in a year, officials added.