Bengaluru's stormwater drain mapping: citizens, data, and research unite for resilient city
Bengaluru's stormwater drain network, spanning 840 kilometres, is the focus of a year-long citizen-led initiative aimed at making the city's infrastructure more transparent and accountable. The 'Building Resilient Bangalore' campaign, led by MOD Foundation in collaboration with Oorvani Foundation and OpenCity, has released a report documenting its first year of work, which combines community participation with data-driven research.
Among the key findings from the campaign's 'Stormwater Drain Data Jam' is that the Vrishabhavathi Valley has a higher number of unauthorised drain inlets compared to other valley systems in the city. In Shivajinagar, 88% of surface area near drains is impermeable, despite an annual expenditure of ₹15-20 crore on drain maintenance. The data also highlighted a clear divide in thermal comfort: areas with lakes, open drains, and green cover acted as heat sinks, while dense built-up areas with closed drains and dry drain beds contributed to urban heat islands.
The project's primary goal is not merely to document drains but to build an open knowledge ecosystem. According to the report, this ecosystem enables citizens, researchers, designers, practitioners, and government agencies to collectively understand and act on the city's stormwater systems. The initiative aims to make this infrastructure more observable, understandable, and actionable.
Over the past year, the campaign has launched several public engagement tools. These include a research framework for studying Bengaluru's stormwater system, a citizen science audit toolkit, an interactive ecology map, and an audit dashboard. Public programmes such as data jams, masterclasses, guided citizen audits, and typology workshops have also been conducted. An open-access repository now compiles spatial information and on-ground observations from these efforts.
Citizen participation has been significant. So far, 235 auditors have taken part in 17 guided audits, covering 40.8 kilometres of stormwater drains. Their observations documented considerable variation in the physical condition of drains, visible signs of poor water quality, solid waste accumulation, and overlapping infrastructure such as electricity poles, pipelines, and manholes located within or immediately adjacent to stormwater corridors.
Naresh Narasimhan, cofounder of MOD Foundation, stressed the need for a fundamental shift in urban water management. "Severe climatic events are increasing in frequency, particularly rain. Eventually, Bengaluru has to come up with blue-green infrastructure where we move away from our disposal mentality to a reuse and recycle mentality, including water. We have too much water; we just have poor management and optimisation," he said.
The campaign is designed as a long-term journey rather than a one-off project. Its first-year report serves as a starting point, aiming to inform future planning and foster a shared sense of responsibility among all stakeholders for the city's stormwater network.
