Patna, April 19: The fast depleting water table in the city has prompted Patna Municipal Corporation (PMC) to decide on revamping its decades-old deep borewells.

Sources in the civic body said PMC has planned to increase the extraction layer of these borewells by about 50m to 100m, as the water table has dipped in the past few years and the amount of water tapped through these wells has decreased.

“In the PMC-empowered standing committee meeting yesterday, it was decided that column rods would be installed in the borewells to enable them to extract water from a deeper layer. The engineering department has been asked to prepare a list in this regard,” said mayor Afzal Imam.

He also said column rods would be installed in all the 87 functional borewells if required.

“There are 97 tube wells through which the corporation can tap water and supply to the city. Ten of them are non-functional, at present. The empowered standing committee has also directed the water supply wing to get them repaired or replaced before water demands peak during summer,” Imam said.

Officials in the urban development department, meanwhile, admitted that the groundwater level in the city is dipping at an alarming rate.

“Every year, it is depleting by around 13cm. According to the report of the Central Ground Water Board, Mid-Eastern Region (CGWB-MER), released last year, the water table has gone deeper by 2.5m over the past two decades,” said a senior official in the department.

According to another study, the groundwater in Patna continues to be at 220m below the ground level, constituting a total reserve of 1,500 million cubic metres. This fulfils about 90 per cent of the water requirement in the city. This water is made available to the citizens either by Patna Municipal Corporation through deep tube wells that tap water in the range of 150m to 200m or by household tube wells that extract water from a range of 40m to 100m.

“The city depends heavily on groundwater sources. PMC draws about 375 million litres per day (MLD) water through its tube wells but the demand is about 250MLD. Of the total water drawn, 46 per cent is lost in transit and the actual volume of water reaching to the tap-end is about 200MLD,” read the report, prepared by the civic agency itself.

According to the estimate prescribed by Jawaharlal Nehru National Urban Renewal Mission, 2006, about 52 per cent of the population in Patna depends on the municipal corporation for its water requirement, while 40 per cent of the households have their own tube wells. The total annual extraction is put at 180 million cubic metres.

Residents, meanwhile, complain that jet motor pumps, installed by individuals in households, to extract and store water, about 10 to15 years back have stopped working.

“I had to replace the tube well of the old pump with a new submersible pump and had to increase the depth of the well to 260ft below the ground well. It cost me around Rs 30,000. In my neighbourhood, many water motors with 150ft to 200ft deep tube wells have stopped working, as the water level has dipped. Many of my neighbours are replacing their tube wells,” said Patliputra Colony resident Sunita Srivastava.