Rampant and unplanned development has badly affected the stormwater drainage (SWD) system in Bangalore, causing instances of urban flooding to rise.
Bangalore requires additional 658 km of stormwater drains to effectively tackle frequent urban flooding, according to a report released when? by property consultants Knight Frank. The report highlights that the interconnection between the water bodies in the city such as lakes and the stormwater drains are severely affected causing recurrent floods in events of heavy rainfall.
Bangalore currently has a total of 842 km stormwater drain network under the Bruhat Bengaluru Mahanagara Palike (BBMP), which is inadequate according to the report. Once called the “city of lakes”, Bangalore’s 285 lakes were interconnected by means of primary drains or Rajakaluves. Free waterflow into these drains and lakes ensured that the excess rainfall did not accumulate and flood the city. However, according to the report unplanned urbanization has deteriorated nearly 50 percent of Bengaluru’s stormwater drainage infrastructure. The percentage of built-up area of in the city increased from 37.4 percent in 2002 to 93.3 percent in 2020.
The Karnataka State Natural Disaster Monitoring Center had identified 226 flood prone areas across the city at the beginning of the year. It had also said that Panathur Main Road and Tubarahalli are two areas which will flood even with 1 cm of rainfall.
Bangalore’s Balagere road, Panathur and Croma road saw floods in June this year. Shwetha, a resident of Belagere said, “We actually dread the rainy season. Rain for even 30 minutes can cause floods. A large number of commuters use the Balagere road, and the flooding inconveniences many.” She added that she has never seen any workers fix the stagnated stormwater drains, even during the rainy season.
An official from the BBMP Mahadevpura office said that multiple works on stormwater drain improvements have started in the constituency and are expected to be complete before 2024 monsoons.
Vishal, a resident of Electronic city, a locality which saw flooding in May along with several other areas, said, “Floods have become a common phenomenon in some parts of Bangalore mainly due to rapid urbanization and loss of green cover. The BBMP must take measures to clear encroachment of drains so that commuting on certain roads does not become next to impossible in the rainy season.”
The civic body currently incurs 1 percent of the total expenditure in the budget towards maintenance of the stormwater infrastructure of the city, which is Rs. 70.2 crore. The Knight Frank report said that in order to expand the city’s drainage network to the ideal 1500 km, the BBMP needs to spend around Rs. 2,800 crore.
The report also suggested the adoption of nature-based solutions such as building sponge city to address urban flooding. A sponge city is urban area that uses natural areas and permeable surfaces to absorb rainwater and prevent flooding. Sponge cities also improve biodiversity and ecology, and address water shortages.
KK Murari, assistant professor at the Centre for Climate Change and Sustainability Studies, Tata Institute of Social Science, Mumbai, said that a number of anthropogenic causes such as encroachment on drainage areas preventing the free flow of water, poor waste management which leads to the clogging up of the drains and lack of green cover can lead to urban flooding. She further said that the concept of sponge city should be adopted by a city like Bangalore which continues to witness unchecked urban sprawl and construction. “Sponge city is basically increasing the capacity of a city to absorb water by replenishing its green cover. It is an effective means to mitigate floods and recharge the city’s groundwater, apart from improving the air and water quality,” she explained.
