Bengaluru is in desperate need of stormwater drainage master plan: Knight Frank India report

India's IT capital, Bengaluru, needs an immediate stormwater drainage master plan and remedial measures to curb urban flooding that has been frequently haunting the city.

The city needs an additional 600km of stormwater infrastructure. The remodelling and expansion of the city’s stormwater infrastructure are expected to cost around Rs 2,800 crore. This was highlighted in a recent report by Knight Frank India, an international property consultancy.

The report pointed out that Bengaluru’s population has more than doubled in the past two decades, and it is likely to reach 18 million in the next decade. It has become very much necessary for real estate and infrastructure to be adequately developed to be able to absorb the population influx. Due to population growth, the land use dynamics of the city have significantly changed. The share of the built-up area of the city 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 stormwater drainage system, has come under severe stress. Primarily, the interconnection between the water bodies such as lakes and stormwater drains has been severely affected, causing recurrent floods in the event of heavy rainfall.

“A master plan should be developed with the involvement of experts, urban planners, environmentalists, and stakeholders to ensure its effectiveness and feasibility. In addition to the master plan, adopting alternate flood-controlling techniques can enhance the city's ability to manage stormwater effectively. By implementing these measures and integrating them into the stormwater master plan, Bengaluru can mitigate the risk of flooding, minimise social and economic losses, and ensure sustainable development in the city. It is essential to prioritise investment in infrastructure alongside the city's economic growth to create a harmonious and resilient urban environment,” said Shishir Baijal, chairman and managing director, Knight Frank India.

Observing that Bengaluru will continue to be one of the fastest-growing cities in the country, the report said to complement the population growth and accommodate the same, the real estate and infrastructure in the city will continue to develop.

The real estate sector has had a significant multiplier effect on Bengaluru’s economy. The city's real estate development comprises about 213 million sqft of 'Grade A' office space which has generated nearly 1.7 million white-collar jobs predominantly by the IT and the ITES sector since 2008. Each of these jobs has the capacity to generate nearly eight indirect jobs in the economy. The multiplier impact of the city’s employment boosts consumer demand, creating demand for real estate, social infrastructure, and transport infrastructure.

The report stated that Bengaluru’s GDP increased from $16 billion in FY05 to $97 billion in FY 2023. Additionally, taxes collected from real estate development such as property tax is one of the key revenue sources for the urban local body BBMP. The unplanned development damages the city’s stormwater infrastructure which in turn leads to flooding during heavy rainfalls. Such instances are very common in growing cities.

The Knight Frank report observed that with the support of urban local bodies (ULBs), some Indian cities such as Mumbai and Chennai have initiated active measures to build and strengthen stormwater infrastructure to support real estate and infrastructure growth and withstand events of excessive rainfall.

The report pointed out that currently, Bengaluru has 842km of primary and secondary drainage. To complement the spatial expansion, the city broadly requires an addition of approximately 658km of primary and secondary drains. As per Knight Frank estimates, the capex requirement for the construction of new drains, in addition to the rejuvenation of existing drains, is estimated to be Rs 2,800 crore. In the long run, financing of such sustainable infrastructure could be challenging as it involves enormous capital expenditure in the form of initial cost along with long-term operation and maintenance costs.

Efficient stormwater management mechanisms have the potential to increase the value of surrounding land and boost real estate development. Therefore, the government authorities can tap into financing through real estate using mechanisms such as Value Capture Financing (VCF).

VCF is based on the principle that private land and buildings benefit from public investments in infrastructure and policy decisions of governments. VCF tools can be deployed to capture a part of the increment in the value of land and buildings. In turn, these can fund new infrastructure projects of the central and state governments and ULBs.

It has also been recommended that Bengaluru can adopt nature-based solutions such as ‘sponge city’ developments to counter 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 concept of a ‘sponge city’ emphasises tackling urban surface-water flooding and related urban water management issues such as purification of urban runoff, attenuation of peak run-off, and water conservation. This approach integrates green spaces and ‘blue’ systems like wetlands into conventional ‘gray’ infrastructure such as concrete embankments, contributing to the 2030 UN Sustainable Development Goal (SDG) to “make cities and human settlements inclusive, safe, resilient and sustainable.”

Interestingly, as per the World Bank, the investment needed to scale up the programme is an estimated $1 trillion by 2030, with the financing gap expected to be covered by provincial and local governments and financial institutions together with the private sector and local communities.