Indiscriminate extraction could dry up groundwater: Geologists

Geologists expressed serious concern over the unregulated withdrawal of groundwater.

“Indiscriminate and unplanned extraction of groundwater could lead to wells yielding saline water for some time and then drying up,” V Subramanyan, a former geology professor at the Indian Institute of Technology (IIT), said. “Even the surface streams may lose their water.”

It was imperative, said Subramanyan, for a coastal city like Mumbai to retain the state of already existing equilibrium between freshwater and saline water. “Excessive pumping of wells or heavy withdrawal of water through several wells located near each other can disturb this balance,” Subramanyan said. “In either case, the underlying saline water encroaches upon the fresh water column and contaminates it.”

SK Gupta, former deputy director of groundwater survey and development agency (GSDA), Konkan Region, said it was important to improve the groundwater levels through rainwater harvesting.

Gupta said that preference should be given to ring wells instead of borewells to improve the quality of groundwater. Subramanyan said that recharge ponds should be built to tackle the crisis.

Between January and June, at least 523 borewells were dug, but the BMC built only 50 ringwells. Subramanyan said it was essential to understand the configuration of the water table by examining the data available with the groundwater survey and development agency.