June 19, 2019
Installation of check dams in the agricultural belts is among the key water conservation schemes initiated in Tamil Nadu after poor rains, depletion of groundwater and failure of river sharing talks with neighbouring states.
In Coimbatore, the scheme under the Mahatma Gandhi National Rural Employment Guarantee Act’s (MGNREGA) guidelines has been active for nearly three years.
Rooban Shankar Raj, project director of District Rural Development Agency (DRDA) told The Covai Post, “ It is basically an initiative to improve the depleting ground water levels and to recharge them. So we build check dams across small streams and tributaries of the Noyyal river.
“Each check dam can help irrigate 5-10 acres of agricultural land. There are about 150 types of check dams to hold in surface water, so that it can be absorbed back into the ground. We build these dams according to the soil surface. Thus concrete dams are built on plain flat areas, boulders for hilly regions and gabion structures (small stone and wire dams) for steeper slopes.”
He added that spiritual guru Sri Sri Ravishankar’s organisation, Art of Living, had voluntarily helped to identify natural water aquifers through GPS or satellite tracking system. A water aquifer, often found 10 feet below the ground, is a body of permeable rock which can contain or transmit groundwater. This has helped DRDA mark out areas where these dams could be constructed.
Rooban gave important statistics on the efficacy of the program. He said, “You see in one acre about 70,000 coconut trees can be planted. So if there is a check dam in the area, leaving out the average 40 days of rain, if you water the trees every alternate day you will be using only 10,500 litres per annum.
“Thus you will have conserved water and grown healthy trees. Our statistics taken every May show that groundwater in Coimbatore was 29 cubic mm height in 2017, 22 cubic mm in 2018 and 17 cubic mm in 2019. So you can see the gradual increase in the water table. We aim to bring it up to 5 to 6 cubic metres by 2022.”
The cost of each dam construction can vary from Rs 90,000 to Rs.1, 32000. “Each construction can last five years so that the stream water levels can really improve by that time,” says Rooban.
Currently he is working in Pidichi taluk in suburban Coimbatore.
This check dam work has also provided livelihood for many impoverished families and unskilled labourers besides teaching them about water conservation.