Two days after a portion of the busy Bhairon Marg in Central Delhi caved in, authorities on Tuesday said they were clueless as to what caused the collapse.
The spot, near Pragati Maidan, has old sewer lines that were laid in the 1950s; coupled with sandy soil, the stretch has seen many cave-ins. The Delhi Jal Board and the Public Works Department (PWD) have engaged in blame games after every incident.
This time, a stretch of road measuring roughly 15 feet caved in on Sunday. The PWD filled it in with soil, but when the team returned on Monday, the soil was gone and the road had caved in further.
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The DJB, which has pipelines under the spot, said that it was still looking for the cause of the incident. “Our team is investigating at the sub-soil level. Our sewers are about 25 metres beneath the surface. We are looking at whether the bed where the lines are laid has been disrupted,” said DJB CEO Keshav Chandra.
He added that there was minor damage to the sewer line, but since the pipe was massive in size, it would take 10 to 15 days to repair.
Kapil Mishra, the chairperson of the DJB, denied that the cave-in occurred because of the DJB. “Sandy soil just caved in, affected the sewer line. We will only know what happened after an investigation of the site,” said Mr. Mishra.
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Meanwhile, a senior PWD official said the agency was only responsible for the surface of the affected stretch, while the onus of maintenance of the sewer and water line below lay with the DJB.
“The DJB needs to repair whatever damage has occurred to the pipeline. We will observe the stretch for a fortnight before we can start reconstruction of the road,” said the official.
The official added that the same stretch of road had caved in two years ago.
The New Delhi Municipal Council area has seen similar cave-ins over the past few years. Apart from Bhairon Marg, a stretch of Ferozshah Road, near the crossing with Kasturba Gandhi Marg, has caved in several times.
Road and design expert Professor P.K. Sarkar of the School of Planning and Architecture said the combined lack of a robust master-plan of the sewer network and a basic traffic management system was to blame.
“Cave-ins are caused by leakage, which weakens the soil base under roads. In most locations where these occur, care needs to be taken to construct roads with more composite strength. These efforts need to be coupled with a technology-driven mechanism to detect and pre-empt such situations close to the monsoon,” prof. Sarkar said.
He added that important factors such as surface and sub-surface drainage were not part of the road design at several locations across the city. “The area under the NDMC is most notorious in this respect,” said Prof. Sarkar.