Property consultancy firm Knight Frank on Wednesday published a report recommending an additional length of more than 600 kilometres of storm water drain (SWD) infrastructure to avoid recurrent flooding in Bengaluru.

The international property consultancy firm also noted that the government should invest ₹2,800 crore on remodelling and expansion of SWD infrastructure.

In its report titled 'Bengaluru Urban Flood', Knight Frank underscored that as Bengaluru is one of the key engines of the country's economic growth, real estate development will continue to expand to accommodate the city's growth.

For long-term sustenance, there needs to be greater emphasis on the cohesive development of real estate and strengthening of supporting infrastructure without causing further damage to the ecosystem of Bengaluru, the consultancy firm said.

To avoid recurring instances of urban flooding, the governing bodies need to rejuvenate and remodel the city's SWD infrastructure, the report mentioned.

In September last year, torrential downpour led to several parts of Bengaluru reeling with flooded roads and several residential localities along with IT companies remaining inundated for days.

"Currently, Bengaluru has 842 km of primary and secondary drains. To complement the spatial expansion, the city broadly requires an addition of approximately 658 km of primary and secondary drains adding up to a total length of 1,500 km," the firm said.

"As per Knight Frank estimates, the capex requirement for construction of new drains in addition to rejuvenation of existing drains is estimated to be ₹2,800 crore," it added.

The Karnataka government in its 2023-24 state budget announced an allocation of ₹3,000 crore for developing stormwater drain infrastructure in the city with assistance from the World Bank, which according to Knight Frank is in line with its estimates.

The consultancy firm said the share of the built-up area of Bengaluru owing to burgeoning population growth has increased from 37.4 per cent in 2002 to 93.3 per cent in 2020.

As a result of rapid and unplanned development, the infrastructure supporting the natural ecosystem of Bengaluru, especially the SWD system has come under severe stress, it noted.

"The interconnection between the water bodies such as lakes and stormwater drains have been severely affected causing recurrent floods in the event of heavy rainfall," Knight Frank said.

The firm has recommended in its report that Bengaluru can adopt nature-based solutions such as 'sponge city' developments as a measure to resolve urban flooding. "Sponge city is a new urban construction model for flood management being implemented in China, aimed at strengthening ecological infrastructure and drainage systems," the report further said.