The study, which assessed the water level in 63 observation wells, indicates that the failure of monsoon and overall rainfall deficit has led to an alarming depletion in the groundwater table in the district.

V. Prasannan, district officer, Groundwater Department, said over the past month the groundwater table at many points in the district had dropped by more than a metre. The biggest drop has been recorded in Rayamangalam, where the groundwater table dropped by 1.81 metres in February. The fall is alarming as the measurement was based on the water level in a bore well, not a shallow well. “Such a vast fluctuation in water level in a bore well is unusual,” department sources said. Between February and January, the water table dropped by 1.30 meters in Muvattupuzha. The situation is no better in Edakkattuvayal (0.42 m), Palamattom (0.68 m), Koothattukulam (.065 m), Kodanad (0.51 m), Ramamangalam (0.31 m), and Kakkanad (0.45 m).

“If the dry spell continues it will adversely affect irrigation and availability of drinking water, besides posing the threat of saline water intrusion in water sources,” said Mr. Prasannan.

Intensive water conservation measures such as building check dams and water holes should be taken during the next monsoon to rejuvenate the water level, he said.

V.N. Sivasankara Pillai, former director, School of Environment Studies, Cochin University of Science and Technology, said rampant sand mining had taken its toll on the water-level in rivers and would lead to a fall in the adjoining groundwater table.

“The State does not have a long-term water policy; it follows an ad hoc policy. At present, the government is using the accumulated River Management Fund to supply water through tanker lorries. That fund too will be exhausted if the situation does not improve,” Mr. Pillai told The Hindu.

Sivanandan Achari, Assistant Professor at the School of Environment Studies, said there was no longer equilibrium between the rate of water percolation and retention in the groundwater aquifer and the rate of consumption. “The water consumption, irrespective of urban-rural divide, has gone up to 150 litres a person per day. We are increasingly getting on par with the United States on that count,” he said.

Rising surface heat coupled with disappearing wetlands, which have high water retention capacity, has led to depletion of the groundwater table. “The revenue or the local self-government bodies do not have a scientific database on groundwater table.”