Bengaluru needs 658 km of new stormwater drains to curb flooding

Bengaluru needs approximately 658 km of major stormwater drains to be constructed in line with the rate of the city's expansion and population influx to curb the risk of urban flooding, according to a report by property consultancy Knight Frank India.

The report released on Wednesday highlights how rampant unplanned development, population influx, and climate change are placing severe stress on the existing drainage system in the city. As a result, the interconnected drainage system has deteriorated and been halved in length since the 1900s and needs upgrading.

Citing CAG 2021’s figures, the report notes that there are 633 stormwater drains within BBMP limits, measuring a total length of a mere 842 kilometres. Owing to the city’s spatial expansion from 226 sq km in 1995 to 741 sq km in 2011 under BBMP limits, the report calls for the remodelling of the infrastructure to construct an additional 658 kilometres of major drains in the city. Knight Frank estimates that the costs for construction, rejuvenation and upkeep of existing drains would be approximately Rs 2,800 crore.

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The study points to how the existing infrastructure falls short in ensuring a free flow of water in the stormwater drains and urgently pushes for the government to tackle this annual issue with a cohesive master plan involving experts for the construction and rejuvenation of stormwater drains in the city.

Rajeev Vijay, Executive Director, Government and Infrastructure Advisory at Knight Frank India, said that the development of a master plan should take approximately six to nine months. "I would say that (it will take) one to one-and-a-half years for project preparation and another two years for implementation,” he said.

Besides the extension of drain length, the report takes China's sponge city model for flood management as an example to urge the government to develop green infrastructure. This move that would create rain catchment areas and avoid flooding can be delivered through the AMRUT (Atal Mission for Rejuvenation and Urban Transformation) program, it suggests.

Revenue generation is not an impeding factor, the report also suggested the adoption of Value Capture Financing (VCF) so the local civic body can tap into real estate to raise revenue for stormwater drain management.

"There is enough revenue collection and it is not an issue but budgeting and spending needs to be prioritised and on-ground action is required," it said.