The municipal corporation wants the new Tallah bridge, which would be built after pulling down the existing one, to leave a 2-metre gap under the road below it so that the water pipes can pass unhindered.

Metro had reported on Monday that the civic body had asked engineers of the public works department (PWD) to prepare the design of the new bridge without disturbing the water pipes.

An official of the Calcutta Municipal Corporation (CMC) said there were 12 water pipes running under the Tallah bridge. While some of the pipes bring water to the Tallah water reservoir from the Palta water treatment plant, some carry water to various parts of Calcutta.

“We want the design of the new bridge to include a 2-metre gap beneath the road under the bridge. This will leave space for pipes to pass without any hindrance,” said a CMC official.

The CMC produces 440 million gallons of potable water every day to cater to around 45.6 lakh people. A little over half the volume is routed through the Tallah tank, which was inaugurated in 1909. “Impact on any one of the pipes bringing water to the tank or taking water away from the tank for distribution can badly disrupt water supply in Calcutta,” said a CMC engineer.

“We cannot afford any situation where pipes linked to the Tallah water reservoir will be disturbed. Water from the Tallah tank is distributed to areas as far as Bhowanipore. Almost the entire north and central Calcutta survives on water from the Tallah tank,” the CMC official said.

Before the plan is finalised, CMC engineers have flagged their concerns so that there is no error in calculation.