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Bengaluru, the capital of Karnataka, is still struggling to find its way out of the ‘Day Zero’-like situation it was facing just three months ago, when the city’s groundwater had plunged to the rocks and municipal supply has slowed down to a trickle.
An analysis by Down To Earth earlier found that cities like Bengaluru are neglecting their local resources and not harvesting the rain, which is behind their water troubles. The Silicon Valley of India was once known for its water wealth in the form of its lakes and waterbodies. Unfortunately, the city has lost more than 60 per cent of its green cover and waterbodies to maddening urbanisation, according to analyses by scientists of Indian Institute of Sciences.
Out of the immediate crisis mode, Bangalore Water Supply and Sewerage Board (BWSSB) — the agency responsible for supplying water and sanitation facilities — has finally made rainwater harvesting mandatory in the city. The Board mandated in 2009 that new residences with 30x40-foot sites either recharge the groundwater table by harvesting rainwater or store it in a sump or tank; the Bengaluru Water Supply and Sewerage (Amendment) Act, 2021 extended this requirement to older constructions on 60x40-foot or larger sites. In 2011, BWSSB even discussed penalising citizens who failed to harvest rainwater in their buildings. The penalty mentioned disconnection of the water supply.
Understanding the relationship between restoration and groundwater recharge is the best approach the city could take — and it is doing so. BWSSB is planning a comprehensive community rainwater harvesting programme to address the city’s ongoing water scarcity and promote sustainable water management practices.
This initiative is intended to collect and store rainwater at the community level, reducing reliance on traditional water sources and mitigating the effects of water shortages during dry periods, as well as the extra water diverted to nearby lakes, which will help the lake maintain its water level and recharge the groundwater.
Sanath Kumar V, additional chief engineer for BWSSB, explained the initiative was not new for Bengaluru as many of the apartments are already harvesting rain to store in the sump as well as recharge the groundwater. “The summers of 2024 were difficult for us, so BWSSB plans to expand the initiative. The board also advises citizens on the design of community-scale rainwater harvesting systems and has a maintenance wing that oversees both community and individual systems. It also has a theme park that displays different models of rainwater harvesting.
In the initial phase of the initiative, BWSSB identified 17 such apartments near the lakes. This initiative will benefit a few lakes, including Saul Kere lake in Bellandur, Hoodi lake and Sheelavantha Kere lake in Whitefield. The maintenance wing of BWSSB selected the apartments, which are 200-500 metres away from the lake and have rainwater harvesting systems installed on their premises as per norms.
The Board prioritised apartments that are within a radius of 100-200 metres of the lakes to ensure effective flow of rainwater into the nearby lakes. This strategy maximises rainwater use and cuts down on the costs of installing long pipelines.
The more rainwater collected, the better it is for the city, according to Vishwanath S, founder and director of Bangalore-based design firm Biome Environmental Solutions that focuses on ecology, architecture and water.
“Connecting lakes with the rainwater from the nearby apartments will help the lake maintain its water level and also dilute the contaminants, thereby improving the water quality of the lakes,” said Vishwanath. However, he cautioned that the maintenance of the pipelines connecting the apartments with the nearby lakes is extremely important for the success of this project.
Ram Prasad, co-founder of the proactive citizens group Friends of Lake, supports the initiative but believes that rainwater from the apartments should first be used for groundwater recharge. Only then should excess water be diverted to the lakes.
“It must be ensured that the apartments divert uncontaminated water. A dedicated pipeline should be built for this purpose. The BWSSB should develop a standard operating procedure for the initiative that includes water quality monitoring, regular operation and maintenance, pollution control, and biodiversity conservation. Only then will these kinds of initiatives be successful,” Prasad said.
