Going, going, down in search of water is the story in several parts of the city. Borewells going down to a depth of 1,500 feet are only yielding a couple of inches of water. In desperation, drillers are now procuring machines that can drill up to 2,000 feet, but experts warn that it would only make it difficult to recharge
Bangalore: Two thousand feet down is fast becoming the new minimum for borewells in the city. Groundwater has been so extensively exploited that across the city drillers are increasingly being told to go beyond 1,500ft. And even at that depth, owners are not assured of a reliable source of water.
It wasn’t long ago when drilling to 1,000ft was considered a high. But with water reaching dead storage level in reservoirs and intermittent supply of water from BWSSB, residents are increasingly looking at borewells to mitigate their water woes. However, indiscriminate drilling has depleted groundwater to such an extent that at 1,000ft drillers are only coming up with mud and dirt.
The pattern is replete across the city. For example, residents in Sarjapur and Hosur routinely drill to a depth of 1500ft. In nearby HSR Layout, residents normally drill to 1,200ft. It’s the same in areas in Devanahalli and T Dasarahalli, while in Yelahanka and Marathalli residents have to go beyond 1,000ft to strike water. And already in Kolar, two residents have drilled to 2,000ft to strike water. Experts say it would soon be the case in the city too.
Drilling is an expensive business. Drilling of up to 1,500 ft costs more than Rs 3 lakh. Going to 2,000 ft calls for special drilling equipment and could cost upwards of Rs 10 lakh. Moreover, experts warn that the deeper the well, the harder it is to recharge which means that the well would eventually turn dry.
Dr T S Suresh of the geology department, Bangalore University, reveals that it’s only in the last year or so that drilling beyond 1,000ft became routine. “As there is no perennial river source near the city, the founding fathers built lakes all around the city,” Suresh said. “These lakes were not only a constant source of water round the year, but they also helped recharge groundwater. However, with rapid urbanisation, lakes were encroached to form layouts. The effects it has had on the water situation in the city and the state of groundwater is there for all to see.”
Prakash D of Kamadhenu Borewell Drillers and Earth Movers confirmed that they are routinely told to go up to 1,500 feet. For example, he said, a resident in Marathalli ordered them to go up to 1,500ft and even then they only got one and a half inch of water. Another borewell drilled in Hunasamaranahalli found only an inch of water at 1,200ft. The chances of these wells going dry are high, Prakash added.
Venkatesh T, a resident of T Dasarahalli, said, “Our area does not get Cauvery water and we were dependent on tanker water. However, as the prices have increased, I decided to drill a borewell. I spent lakhs of rupees, but couldn’t get water even at 1,000ft. I decided to try for another 100 feet and luckily, I found water at 1,100 feet.”
Kavita Singh, a water diviner, revealed that until now, drillers in the city had the capability to drill only up to 1,500 ft.
“However, a famous builder in the city recently imported machines that can dig to 2,000ft,” she said. “Now many borewell drillers are procuring techniques so that they can go beyond 2,000 ft. The day is not far off when even 2,000ft deep borewells will be common across the city.”
Experts warn that more and more residents drilling wells beyond 1,000ft is a dangerous trend. Speaking to BM, noted hydro-geologist Dr T J Renuka Prasad said his team had been experimenting with deep borewells for quite some time on the Jnanabharati campus.
“Our research shows that there is a high occurrence of fluoride content especially with water draw from beyond 1,000ft. Moreover, at greater depths, recharging borewells would become difficult. This can have two effects. The borewell may go dry which means there are chances of digging deeper borewells. And deeper borewells means drawing water with high fluoride content. Our experiments at Jnanabharati campus has shown that if the borewell is very deep, recharge is negligible and contamination cannot be easily reduced.”