The Hindu             29.11.2013

‘Set up ground water authority to check drilling of borewells’

: Setting up a ground water authority consisting of experts and imposing a moratorium on private borewells are essential to check the indiscriminate drilling of borewells, says an expert.

V. Mahesha, an expert in hydrogeology, has suggested that it will help undo the damage that has already been done to the groundwater table.

It was reported this week that more than 25 per cent of coconut trees in Chamarajanagar district have died and the phenomenon is spreading. It is being attributed to depletion of ground water.

It has also been reported that when it rains, the ground is moist for a few days and it dries up quickly. It is affecting other crops too, according to Mr. Mahesha.

Indiscriminate drilling of borewells is the most probable cause for such drastic depletion of ground water. Geologists have known for some time that depletion of water table in areas of high borewell density is far in excess of what is expected after taking into account rainfall variations and the increased ground water usage (which is now more than 20 times the use in 1960), he explained.

Deeper Zones

“So, there has to be another reason. It has now been confirmed that ground water in the tight fracture-controlled aquifers in the State has found vents in borewells for free flow from shallow zones to deeper zones,” Mr. Mahesha, a member of Mysore Grahakara Parishat, observed.

“Borewells are draining water into the earth. The land has become a sponge which sucks rainwater and sends it directly to deep underground,” he explained.

As a result, he said, the surface runoffs have also diminished limiting the flow to tanks, tributaries and rivers.

This is also the reason that even a perennial river like the Cauvery is getting depleted, he said in a release here.

“In such a situation, shallow ground water cannot be recharged. Water directed underground by recharge pits will directly flow into deep underground and will not raise the water table. This has happened in many places in Karnataka where a large number of borewells have been sunk,” he said.

“If the drilling of borewells continues at the current pace, we will soon reach a point when all surface water will be drained into the deep underground and we will be left with no accessible water at all. Dryland agriculture will then die and the land will turn into a desert,” he warned.

Steps such as creation of subsurface check dams, plugging the vents (that allow water to flow from a shallow zone to a deeper zone) and recharging aquifers which are not drained to lower levels should be pursued with great urgency, he said.