City running out of ground water

City running out of ground water
By Bala Chauhan DH News Service Bangalore:
The groundwater situation is in a critical condition in Devanahalli, Doddaballapur, Nelamangala, Bangalore East (Whitefield and adjoining areas) and Hoskote, according to officials from Department of Mines and Geology.

Planning to invest in property in Bangalore? Make sure that there is adequate surface water supply and a provision for rain water harvesting because groundwater resources in both the Bangalore Urban and Rural districts are already in the red.

In several residential areas, especially in Bangalore North and East, borewells are dry or on the verge of drying. Ironically, these areas, recording meteoric rise in land prices, are among the “most critical” areas as far as groundwater is concerned.



Critical condition

“Though the groundwater situation is in a critical condition throughout Bangalore Urban and Rural districts, the worst hit are Devanahalli, Doddaballapur, Nelamangala, Bangalore East (Whitefield and adjoining areas) and Hoskote,” said a senior officer from the Department of Mines and Geology. “In these areas, groundwater utilisation is more than 100 per cent of annual recharge and there’s no further scope for exploitation. People have drilled borewells but these are not going to be sustainable sources,” he said.

One of the signs of the sinking water table is the depths to which borewells have been drilled. In some areas borewells have been drilled up to 1,200 feet, he added. Bangalore’s future commercial nerve centre – Devanahalli – is sitting on a virtually dry water table. The Bangalore Water Supply and Sewerage Board (BWSSB) is currently supplying five lakh litres of non-potable water per day to the Bangalore International Airport Limited (BIAL).

The requirement

“The potable water requirement will be another five to 10 lakh litres per day, which we will try and feed through the Cauvery river. But for the Devanahalli industrial township, we will have no option but to supply treated and recycled waste water, after obtaining permission from the government,” he said.

“For residential areas in Devanahalli, people will have to ensure rainwater harvesting and the government will have to set up a reverse osmosis (RO) plant as a long term measure,” he said, adding that the BWSSB is insisting that property developers and builders ensure rain water harvesting in their masterplan.

“The situation has worsened in the last three years. The average annual rainfall in the district is only 600 mm to 700 mm per year. Because of the drought in 2001, 2002 and 2003, groundwater recharge has been very low. Bangalore is entirely dependent on rainfall because it is built on a plateau, on different hydrological basins of South Pinakini and Cauvery rivers,” another officer from the Department of Mines and Geology said. “It’s time the government declared a five-year holiday to exploitation of groundwater.”



A CRISIS IN THE MAKING

According to the report on groundwater resources of Karnataka in March 2004 (the last five-yearly report on groundwater resources) by the Department of Mines and Geology, though the total annual groundwater recharge in Devanahalli was 6,496.65 hectares per metre (HAM), the gross groundwater draft for all uses was 14,294.31 HAM. In Bangalore North, the total annual groundwater recharge was 6,943 HAM and the overdraft was 13,132.21 HAM. In Bangalore South, the groundwater recharge was 6543.16 HAM and the overdraft was 11,856.63 HAM.

“The figures show that people have not only over-exploited groundwater, but have also drilled into the static water reserve, which should be used only in emergency situations,” said a department official.