Wet year pushes up Karnataka's groundwater levels

Heavy rainfall and floods may have led to huge crop loss this monsoon but there is reason to cheer as groundwater levels in the state, even in arid districts like Kalaburagi, have risen sharply. There is a steep rise in the water table in 211 out of the 233 taluks in the state, according to Ground Water Directorate data from May to Nov 2022.

The groundwater level in Nelamangala in Bengaluru rural district has witnessed a record increase of 32.44 m. Water is now available at 17.94 m while in May it was 50.38 m. As many as 24 taluks including Hoskote, Devanahalli, Gauribidanur, Chikkaballapur, Malur, Jamkhandi and Badami have recorded at least a 10-m rise in the groundwater table. Groundwater is now available at a depth of 10 m in 186 taluks. A mere 94 taluks had this level at the start of the monsoon.

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“Pre- and post-monsoon data through 10 observation borewells in every taluk shows a remarkable increase in levels due to heavy rain. The irrigation department has taken up water harvesting schemes like check dams, percolation tanks, borewell recharge pits,” says Ground Water Department director Ramachandraiah.

Even in Ballari, Vijayanagar, Davangere, Kalaburagi, Raichur and Yadgir districts, groundwater level is available at a depth of 5 m.

“Most of the 20 borewells in our village were defunct 3-4 years ago. Now, all borewells are working and the lake has reached its brim due to abundant rainfall,” says farmer Mallikarjun Avanti of Kodli village in Sedam taluk.

Officials claim that lake revival projects have also impacted groundwater positively. “The government has launched a project of filling 4,500 big lakes out of around 33,000 lakes. Abundant rainfall during the last two years has helped the project,” an officer said.

Overflowing rivers have also contributed to the rise in groundwater levels.

On the contrary, 22 taluks have recorded a marginal drop in groundwater levels of about 3 m. Nagamangala taluk in Mandya district has recorded the highest drop by 25.11 m. Gangavathi in Koppal district has witnessed a fall in water levels by 10 m. Experts attribute this to evaporation. They emphasise the need to actively work on conservation activities. If indiscriminate drilling for borewells continues, 80% of the water table will be affected.

“Karnataka has received three times more rainfall than the average during the last two years. Water evaporation due to sunlight and wind can be reduced if vegetation is improved. Micro-climate conditions should be created and afforestation needs to be taken up,” says hydrogeologist and rainwater harvesting specialist Devaraj Reddy N J.