JOIN USBigger borewell diameter cause for deaths: Experts
The death of at least five children in recent months, after falling into abandoned borewells, has thrown light on one key aspect. That of the diameter of the borewell pipes.
The stipulated diameter is four inches. But these days, people go for pipes that are six inches or above in diameter, based on advice by drillers.
Experts say the myth that bigger the diameter more the yield of water makes people go for borewells with diameter as big as 12 inches. Drillers perpetuate the myth as they get handsome returns from borewells with bigger diameter. According to A R Shivakumar of the Karnataka State Council for Science and Technology, water yield depends on the aquifer under the ground and not diameter of the borewell.
Recently, Pratap S wanted a borewell dug at his residential site on Magadi Road. The driller advised him to go for a six-inch pipe to get a better yield of water. “He told us that nowadays nobody uses four-inch pipes.”
Bharati N, a resident of Horamavu, had a similar experience. “Our driller told us that there were construction activities going on nearby and to get good yield of water, we should use six-inch pipe.” Drillers insist that they are right.
Sujata, a Katriguppe-based driller, said substantial water was guaranteed by using pipes of diameter above six inches. Naveendra Reddy, a driller from Yelahanka, said these days nobody preferred four-inch pipes.
Death traps
He said they advise site owners to use six or seven-inch pipes and for apartments or commercial spaces 12-inch pipes. Since wider borewells have become the norm, they have turned death traps once water has been sucked out and the well is abandoned. In Karnataka, in recent months, at least five children have fallen in these wells and died, officials said. The latest victim was a boy in Bagalkot and a girl in Bijapur.
The other reason for leaving borewells open is to ‘facilitate’ rainwater harvesting, with the mistaken understanding that it increases water recharge in surrounding areas immediately, officials said.
According to Mines and Geology department officials, only four inch pipes should be used for borewells. This is because when the casing of the pipe is removed, the drilled hole becomes wider by two more inches. Though the Supreme Court has issued guidelines for drilling borewells, they are not followed.
In Bangalore, there are an estimated 97,969 borewells. At least 7,000 applications are awaiting sanction.