The demand for drinking water is increasing rapidly in Bengaluru with each passing season. As a result, officials at the Department of Mines and Geology claim, the number of applications for inspection of bore well drilling sites coming from the Bengaluru Water and Sewage Supply Board have also increased in the past few months.
While the final approval for a bore well on a site is given by BWSSB, the inspection of the site is done by the Department of Mines and Geology.
Prasanna Kumar, senior geologist with the department in Bengaluru, told The News Minute that they have hundreds of applications pending for inspection. He says that with over 3 lakh bore wells in the city and over a 100 new wells being added every month, there is a serious problem of over-exploitation of groundwater.
“In the month of April alone, the department got over 300 applications for inspection,” he said.
The department officials feel that if Bengaluru continues to depend on bore wells, then there will soon be a time when ground water will be totally depleted. One geologist, who did not want to be named, said that at the rate at which the demand for drinking water from bore wells is rising, Bengaluru's ground water table might run dry in just the next 10 years.
Community bore wells
While a single bore well can supply water to four houses, most Bengaluru-residents want a bore dedicated to their house, claims Prasannakumar adding that a culture of the community bore well, where one bore can supply to a group of houses, should set in.
“Today there are people who dig bore wells 10 metres apart, whereas the recommended distance between two bore wells is 250 metres,”he said.
The drastic dip
According to him, there has been a three-fold dip in the water table in many areas in Bengaluru urban district since 2005.
“There is a dip in the water level by 120 feet every 3 years. This is called a cone of depression: when one bore near another is deeper than another, the water table also dips,” Prasannakumar said.
“Two years ago water was struck at 250 feet in areas around Mallathahalli lake in south Bengaluru, but now water is not found until the ground is drilled to at least 450 feet,” he said.
Electronic City is the worst affected as water cannot be found even at 1,300 feet. However, people who fail to understand that even bore wells can go dry, are ready to pay any amount to get bore water.
“In areas in Bengaluru south which are in a better state compared to others, water is only struck at a depth of 550 to 600 feet. Even those are high on nitrates and fluorides, but people don’t care even when they are warned about it,” said another geologist who didn’t want to be named.
“Sometimes in these areas where the ground is drilled for more than 500 feet, there is a fear that sewage and drain water might enter the ground water through gaps and then the whole point of having a bore well is gone,” he said, adding that it is high time residents started adopting rainwater harvesting as an alternative method of ensuring water supply.