The floods resulting in torrential rain that started on the night of Sunday 19th May 2025 in Bengaluru shows how decades of mismanagement of lakes and waterbodies is creating both urban floods and shortage of drinking water in the city. What can city administrations in India learn from this.

Shri D K Shivakumar, the Deputy Chief Minister of Karnataka expressed his solidarity with the affected people and pointed to the roots of the problem when he tweeted on Monday morning: “Let us be clear: the issues we face today are not new. They have been ignored for years, across governments and administrations.”

When we look back we are struck by the irony that Bengaluru, once celebrated as the “City of Lakes,” is now battling two interconnected but seemingly contradictory crises: acute drinking water shortages and recurrent urban flooding. These dual challenges expose a deep failure in urban water management, particularly the neglect of rainwater harvesting and the mismanagement of the city’s historic lake systems. Rather than leveraging these natural assets to secure water and prevent floods, unchecked urbanization, poor governance, and ecological disregard have turned Bengaluru into a cautionary tale of missed opportunities.

The city relies heavily on the Cauvery River—accounting for over 70% of its water supply—and on groundwater, both of which are severely overexploited. Bengaluru faces a daily water deficit of over 500 million litres, giving rise to tanker mafias and unaffordable water prices. Groundwater levels are depleting rapidly—dropping by 10 to 12 feet annually—while erratic rainfall further deepens the crisis.

Ironically, despite water scarcity, heavy rains often inundate roads and homes, as seen during the floods of 2022 and 2023. This is largely due to the loss of lakes and wetlands, widespread concretization and encroachment, and inadequate urban drainage planning. The paradox of flooding in a water-starved city underscores a fundamental failure in sustainable water governance.

While the Karnataka government passed the Bengaluru Water Supply and Sewerage (Amendment) Act in 2021 mandating rainwater harvesting for buildings, implementation remains weak. Compliance hovers around 30–40%, hindered by poor enforcement, limited monitoring, and a lack of incentives. Bengaluru receives approximately 970 mm of annual rainfall—enough to meet around 40% of its water needs if properly harvested. Decentralized rainwater harvesting, which links rooftop capture to recharge wells, could both reduce flooding by diverting stormwater from drains and help replenish groundwater, easing pressure on the Cauvery and borewells.

Historically, Bengaluru’s lakes formed an interconnected network that functioned as natural rainwater storage and recharge systems. These lakes absorbed excess rainfall, prevented flooding, and replenished underground aquifers. Today, however, over 90% of them have been encroached upon. Around 70% are polluted with sewage and industrial effluents, rendering them unfit for recharge. As these lakes are no longer hydrologically linked, natural drainage has been disrupted, exacerbating flood risks.

For over two decades, the Indian Institute of Science (IISc), in collaboration with the Bruhat Bengaluru Mahanagara Palike (BBMP) and the Ashoka Trust for Research in Ecology and the Environment (ATREE), has advocated for the revival of Bengaluru’s historic “valley system.” This 16th-century design used the region’s undulating terrain to direct rainwater through a cascading series of interconnected lakes, helping to manage floods and recharge groundwater. While the system was scientifically reinforced in the 19th century, it was all but destroyed by the explosive urban growth following the IT boom of the 1990s.

Despite repeated BBMP announcements of ambitious plans to revive the city’s dying lakes, progress has been limited, hampered by top-down decision-making and ecological missteps. Community exclusion remains a core issue, as local stakeholders—such as fisherfolk, urban farmers, and resident groups—are often left out. In many instances, lake rejuvenation is mistakenly treated as an urban beautification exercise involving dredging, concretization, and tree-felling, resulting in what environmentalists term “soup bowl lakes”.

These misguided approaches were widely adopted in CSR-funded projects until legal interventions by the National Green Tribunal in 2018 and the Karnataka High Court in 2019 imposed strict conditions on lake restoration. Today, all such projects must comply with the Karnataka Tank Conservation and Development Authority’s Lake Conservation Guidelines (2020), which mandate environmental clearances, public consultations, and prohibit alterations to lake topography or access restrictions.

As opposed to the sterile containers of dead water that “soup bowl lakes” are, ecologically rich waterbodies should have shallow, wide, and irregular margins to allow wetland formation and groundwater recharge. Linkages to watersheds via natural drains and groundwater systems. Seasonal water level fluctuations to support aquatic life and recharge. Native aquatic plants (e.g., reeds, lilies) to oxygenate water and filter pollutants. Provide diverse habitats for fish, birds, and amphibians. Have wetlands and riparian to have natural aeration and process wastewater, which must be treated before being allowed entry into the waterbody. Fishing, farming, and cultural access preserved for livelihoods, for communities that depend on these spaces. It is only these kind of waterbodies that can absorb floodwaters and recharge groundwater.

Jakkur Lake in north Bengaluru offers a hopeful model for what can be restored. A 4-million-litre-per-day sewage treatment plant processes wastewater before it enters the lake. The treated water is then filtered through a constructed wetland planted with native species such as reeds and cattails, which remove excess nutrients. The lake now functions as a rainwater harvesting structure, replenishing local aquifers and supporting nearby borewells. It also mitigates flooding by absorbing excess runoff during monsoons and sustains a rich ecosystem, hosting over 130 bird species, including migratory birds. The lake’s revival is a result of collaborative efforts between the BBMP, local residents, and IISc researchers.

ActionAid Association engagements on this issue has been at multiple levels. During urban floods we strive to provide humanitarian relief to affected households, as has started on Monday 20th May 2025. As an immediate response we have provided cooked food. As a continued response we have in the past also supported in re-building affected housing destroyed by floods. For decades we have worked with community-based organisations of informal workers who live in informal settlements that are most vulnerable to both urban floods and shortage of drinking water. We stand in them in their efforts to secure rights and entitlements including housing and access to public services.

At another level ActionAid Association has been actively engaged in efforts to restore Bengaluru’s lakes and their ecosystems, seeing them as vital components of the city’s urban ecological commons. In partnership with government agencies and through public awareness campaigns in the press and on social media, we have closely tracked negative developments affecting six lakes in South Bengaluru. We have conducted lake water quality studies across Karnataka, monitored pollution sources, and supported civic efforts to press the Karnataka State Pollution Control Board (KSPCB) to publish comprehensive 32-parameter water quality data—publicly available since July 2023. In collaboration with CSR partners, we have implemented and documented lake rejuvenation projects and promoted public understanding of their importance. Our biodiversity reports for Doddakallasandra Lake and Dorekere Lake detail local plant species, bird populations, and butterfly diversity.

The extremely heavy rain on Sunday night in Bengaluru will have broken some records, and news reports quote Shri Maheshwar Rao, the Chief Commissioner, BBMP as saying that “the infrastructure isn’t designed for this [kind of rain]”. With climate change manifesting itself most dramatically in the increased frequency and higher intensity of extreme weather events, city administrators will have to prepare better. One way of doing this is to critically examine how past infrastructure worked, how communities can be involved and nature-based solutions explored.

Rain is a gift, and in India, we have traditionally welcomed it. Yet in Bengaluru, and in many other cities, flawed urban planning has turned this blessing into a curse – a cause for crises. Modern India still depends on ancient climatic rhythms—but we must build urban systems that transform rainfall into resilience. This begins by safeguarding our urban ecological commons and recognizing the crucial role of local communities—fisherfolk, farmers, and pastoralists—as stewards of these spaces. Only then can our lakes, forests, and grasslands serve as the lungs, kidneys, and shock absorbers of climate-vulnerable cities. Otherwise we will only witness further instances of nature’s blessings turn into curses.