The civic authorities are set to lay a second water pipe between Tallah and Palta to avoid disruption in supply because of problems in the 140-year-old main line.
Taps had gone dry in Calcutta for 36 hours in 2006 after the water mains under BT Road sprung a leak near Baranagar.
“We should not allow water supply to be disrupted again. That’s why we are planning another pipeline between Palta and Tallah,” said mayor Bikash Ranjan Bhattacharyya.
The technical proposal for the Rs 307-crore project was cleared by the Jawaharlal Nehru National Urban Renewal Mission on Tuesday.
“The project will take around three years to be completed,” added Bhattacharyya.
About 260 million gallon of filtered water from Palta feeds taps in 200,000-plus households and 10,000 business establishments in addition to 17,000 stand pipes.
The treated water is first sent to the underground reservoirs in Tallah through a pipe 5 feet in diameter. The water is then pumped into the distribution network via a 9-million-gallon overhead tank. The 23-km pipeline will be 5 feet and 4 inches in diameter.
“During the repairs in 2006, we had to shut down Palta waterworks and cut off water supply as there was no additional feeder line. We cannot repair the old pipe unless there is another line,” said municipal commissioner Alapan Bandyopadhyay.
The holes in the 60-inch water mains were plugged in 2006 with hundreds of wooden pegs.
The CMC will cough up Rs 150 crore from its coffers for the new pipe, added Bandyopadhyay.
To avoid traffic snarls, the civic body will lay at least half the length of the pipe through micro-tunnelling, said chief engineer (water supply) Bibhas Maity. Police had expressed apprehension about traffic snarls if BT Road were to be dug up.
According to Benchmarking and Data Book 2007 of the Asian Development Bank, the water supply network in Calcutta springs more leaks than in any other city in India. On an average, 77,197 leaks appear every year in the water mains and distribution lines in the city.