KOLKATA: More than 50 buildings have been damaged and nearly 500 residents evacuated in the last four days following subsidence because of water seepage into the East-West Metro tunnel at colonial Bowbazar in central Kolkata. In the first phase, 18 families were evacuated on Sunday and lodged in local hotels. More families were evacuated from their apartments and houses after other buildings were declared unsafe on Wednesday.
The Kolkata Metro Rail Corporation (KMRC), the implementing agency, accepted the chief minister Mamata Banerjee’s proposal to give one-time compensation of Rs 5 lakh each to the families who have been evacuated. So far, 70-odd families had to be shifted from the area and some more families might have to be moved in the next few days.
An official of the KMRC said the agency would rebuild the damaged structures and make alternative accommodation for the affected families till their houses are reconstructed.
Firhad Hakim, mayor Kolkata Municipal Corporation, said, "Experts will examine the condition of the soil where the damaged houses are located. If the reconstruction of buildings is not possible, the affected families will be rehabilitated to other places in the city."
Local residents, who have been living here for three generations, got no time to bring out all their valuables. "I saw the floor caving in and managed to take out my jewellery, cash and some important documents. A portion of concrete collapsed in front of my eyes. I ran out of my own house," said Srabani Dutta, a homemaker.
Ratan Das, a tenant in one of the buildings for the last 25 years, said, "I failed to get access to my bed-room where my documents are kept. A portion of the roof collapsed blocking the door of the room."
The KMRC has suspended the tunnelling work since Sunday. Two buildings collapsed in the last four days while eight others caved in partially. A preliminary investigation by the KMRC revealed the houses started developing cracks on Sunday afternoon following soil subsidence after the tunnel boring machine of the ongoing project hit a water pocket.
Sources in the KMRC said the company assigned the contract to build the tunnel was aware about the mammoth aquifer. "It starts 5 metres under the surface and extends till 24 metres. It is extremely risky to take the tunnel boring machine through the huge water-pocket without proper precautions. The machine gave in after travelling 200 metres because of the water pressure," said an official of the agency.
Those managing the work were aware of the risk, said the official. "They had planned twice to inject grout from above, but both attempts proved futile," he said.
The 16.5 km East-West corridor will connect Sector V with Howrah Maidan and run under the Hooghly. The first phase, the stretch between Sector V and Salt Lake stadium, is likely to be operational around Durga Puja. The East-West Metro project missed multiple deadlines and the mishap would trigger a delay for an indefinite period, said a Metro official.
The area under which the tunnel-boring machine was moving is dotted with century-old buildings and narrow lanes. The worst-hit buildings, which are directly above the tunnel boring machine, are located along Syakrapara Lane and Durga Pituri Lane off BB Ganguly Street.