BBMP swamped by criticism over wobbly retention walls

Officials and contractors missed the three-year deadline to finish building retention walls

The BBMP cannot be faulted for the lack of foresight when it comes to solving the flooding issue, especially when it had planned a Rs 1,300-crore complete overhauling of the stormwater drain network in 2018.

While the plan was to build retention walls on either side of the drains to ensure water does not overflow, the Bruhat Bengaluru Mahanagara Palike (BBMP) has missed the three-year deadline. The worst thing is that the walls it had built so far have also crashed in several places, resulting in flooding. The widespread flooding is, therefore, the result of poor and incomplete work by the contractors.

The BBMP’s data showed the length of Bengaluru’s SWD network to be 842 km.

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“Out of the 842 km, we have so far constructed a retaining wall along 464 km. Another 378 km is pending. Largely, the flooded areas are located alongside the incomplete SWDs,” explained a senior engineer with the BBMP.

BBMP Chief Commissioner Gaurav Gupta said the construction process is capital-intensive and must, therefore, be taken up in phases. “The government already approved a few works, which are being implemented,” he said. “We are planning to take up work on another 125-km stretch and are identifying areas prone to floods that need immediate attention. Once that is finalised, we will propose it for capital funding.”

Gupta noted that the project is part of creating fresh infrastructure and is long-term, spanning many years.

Work at snail’s pace

The work’s slow pace, however, has left the Palike in a fix. Despite citizen groups venting their ire against the government, BBMP officials claimed that they are making steady progress.

“By 2018, we had completed 389 km and in the last three years, we have done about 75 km work,” another engineer explained. A contractor working in one of the stretches of the wall building said a kilometre of construction will cost at least Rs 5 crore. The BBMP has granted Rs 1,300 crore in 2018 under the CM’s Navanagaraothana Scheme to complete the project in three years. But officials and contractors have fallen woefully short of the deadline.

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Rampant encroachments along the drains have also hindered the work.

“Without removing encroachments, we cannot construct a retaining wall,” said a senior BBMP engineer. “Encroachment removal must be a continuous process till we build the wall as encroachers tend to return if no action is taken for a long time.”

BBMP’s Chief Engineer (SWD) Suguna said officials are working hard to remove the encroachments. “Officials from the SWD wing are working together with zonal revenue officials in identifying and removing encroachments along the SWDs. The SWDs in the outer areas have the most number of encroachments,” she said.

Walls come crashing down

Despite the BBMP’s claims of progress, walls built in different localities have been collapsing, revealing the poor quality of work.

In June 2020, a 140-metre stretch of the retaining wall along the Vrishabhavathi Valley on Mysuru Road crumbled and flooded the adjoining areas.

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A similar collapse occurred in October 2020 in Hosakerehalli limits flooding Dattatreya Nagar and Pramod Layout in RR Nagar Zone. Such is the effect that these areas continue to experience intense flooding even when it rains for a few minutes in South Bengaluru.

Gupta acknowledged that the walls have collapsed in some places. “There may be some exceptions. But not all construction has come off,” he said. “These would have perished as they had been built several years ago. At some places, the walls have crumbled due to an increase in hydrological pressure.”

An engineer explained that retention walls built with side stone masonry till 2005 were vulnerable.

“Over time, these walls have become weak. But now, we have been building with the RCC technique. We are also looking to remodelling the old walls," the engineer said.

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