Residents must tap shallow layer of water table for better rainwater harvesting during monsoon: Rain Centre

.Groundwater table in Chennai stable for two yrs; Rain Centre suggests tapping shallow aquifer for rainwater harvesting to mitigate local floods. Tube wells & open wells can help conserve resources. Water level varies between 2m-8m; more attention needed to recharge water table. Residents can alternate between groundwater & municipal water. Rain Centre suggests larger diameter open wells & tube wells of max 40ft depth.

The average groundwater table now remains within a depth of 10 feet in many parts of Chennai, according to a survey made by Rain Centre, a voluntary organisation dedicated towards creating awareness on rainwater harvesting.

With the groundwater level available within a few feet below the surface in many areas, experts suggested that city residents must consider tapping shallow aquifer for better rainwater harvesting during rainy days ahead. Tube wells and open wells would help conserve resources and also mitigate local floods.

Sekar Raghavan, director, Rain Centre, said groundwater table in Chennai has been stable for two years now. “We noticed that groundwater was available within a few feet in places like Adyar, Egmore, Mylapore and Mandaveli. In some of the open wells in T.Nagar and Besant Nagar, the water table is now at 7 feet and 10 feet respectively,” he said.

According to groundwater data compiled by Chennai Metrowater, the water level across the city now varied between a depth of two metre and eight metre. One of the reasons cited for the drop in water level in areas like Ambattur, Agaram and Perungudi was more groundwater extraction. It also indicated more attention needs to be given to rainwater harvesting to build the water table.

Mr.Raghavan said while southwest monsoon helped in recharging the water table by a minimum of one metre, northeast monsoon could facilitate an increase of water level by a minimum of 2-3 metre.

“It is not late to tap the groundwater in the shallow layer available within a few feet. This would also save many areas from local floods. Residents may alternate between groundwater and municipal water supply for their needs,” he said.

More residents are now seeking the help of the Rain Centre to dig open wells and sink tube wells. Mr.Raghavan suggested that residents may go in for a larger diameter between 4 ft and 6 ft to enable deepening of the open well later when the water table depletes.