Date:25/11/2008 URL: http://www.thehindu.com/2008/11/25/stories/2008112556950300.htm

Tamil Nadu

Man-made lakes for groundwater recharge in Karaikal district

Shyam Ranganathan

SAVING WATER: The man-made Nallambal lake in Tirunallar commune.

KARAIKAL: Groundwater recharge and conservation of Cauvery water are important for the tail-end region of the delta. And the man-made lakes created by the Karaikal district administration serve both purposes, officials say.

Being close to sea, Karaikal does not have good groundwater supply due to seawater intrusion.

Engineers say that deep borewells are needed in places to access sweet water, and even these deplete the available water at a high rate. Another issue with the district is the wastage of Cauvery water flowing into the sea in the monsoon season.

Over five tmcft of water flows into the sea through the seven tributaries of Cauvery that flow through Karaikal, a PWD official says.

“We decided to acquire 32 hectares in Nallambal and over 6 hectares in Chettikottagam to create lakes that will raise the water table and conserve the water running waste into the Cauvery for useful purposes,” N.Vasanthakumar, Collector, says.

The lake at Nallambal in Tirunallar commune, with a capacity of over 28 million cubic feet, was created at a cost of Rs. 40 lakh. The Chettikottagam lake cost Rs. 25 lakh, and both were created taking into account availability of water throughout the year.

“We make sure there is a minimum of 1.5 m depth of water at all times. We have taken into account losses due to evaporation in the dry months, and divert water through special shutters when there is excess in the monsoon season,” an engineer in the PWD says.

While the immediate effect of raised water table is clear according to residents, the lake also helps the farming communities nearby. The Collector says he wants to develop the area around the lake as a tourist spot with boating and other recreational activities.

Some birds have also started coming to the watering ground, locals say. Fish culture and other industries can also be taken up. The soil that was dredged out for creating the lake has itself helped create fertile lands in nearby areas, say officials.

In fact, Dr. Vasanthakumar believes that the Nallambal and Chettikottagam lakes are successful enough to warrant the creation of more lakes and says he has sent proposals to that effect.