Navigating floods in Bengaluru: a natural way forward

The flood area of ​​Sai Layout in Bengaluru on May 19 after rain on May 19. Photo Credit: Sudhakar Jain

Urban floods in Indian cities have become a frequent and growing challenge, in which Bengaluru is experiencing rapid and disruptive flood incidents. In 2024, Bengaluru suffered severe floods with over 2,000 houses. Bruhat Bengaluru Mahanagara Palik (BBMP) said that within six hours the Yalehanka region recorded 157 mm of rainfall, resulting in over 1,030 houses flooding. Heavy rains widely promoted waterfalls and traffic congestion, which severely affected daily mobility and resulting in a temporary road closure across the city. While climate change and irregular monsoon factors are contributing to the underlying issues plan, land usage, and the management of infrastructure, it has long been stems from systemic intervals.

Traffic was diverted due to waterlogging near silk board junction after heavy rains. , Photo courtesy: K Bhagya Prakash

Nature-based solution

Historically, urban planning in Bengaluru and other cities across India has emphasized the removal of storm water from the city border. Since the sources of drinking water in cities are outside the metropolitan area, urban development strategies preferred efficient storm drainage rather than local water retention or recharge. This led to widely worked of storm water drains and a planning paradigm, which was seen as a problem of expels rather than a resource to manage rain water. Over time, unplanned urban expansion and weak enforcement mechanisms were allowed by private and government actors for encroachment of water bodies and stormy water channels. Additionally, the disposal of liquid and solid waste has greatly reduced the natural water-holding capacity of the water drains and water bodies, which increases the vulnerability of the flood.

Flood area in Sai layout after overnight rain on 19 May. Photo Credit: Sudhakar Jain

In this context, nature-based solutions (NBS) provide a promising and scientifically grounded approach to urban flood mitigation. Green infrastructure interventions such as rain gardens, wetlands, bioses, green roofs, and permeable pavement can slow, stores and filters rain water, providing ecological and social co-profit. Globally, many cities have adopted such strategies under the structure of “sponge cities”. A remarkable example is Gwanging district in Shenzhen where NBS intervention has resulted in a decrease of 72% annual runoff control rate and 62% in varied pollution. These results were obtained through a combination of decentralized green infrastructure, improving water and waste water systems and combining active community engagement.

After heavy rains on May 19, HRBR layout flooded photo credit: Sudhakar Jain

Posted well for redisine

Bengaluru is well deployed to test and score nature-based solutions. Known as “Garden City”, it has more than 1,100 parks and more than 250 playgrounds, distributed in eight municipal areas. There are also green places in many apartment complexes and educational/private institutions that can be rebuilt or extended for storm water retention. These existing assets provide a strong foundation to absorb the city and manage runoff.

Further in a practical way selective wards will involve piloting NBS, with a combination of experimental and control wards to allow comparative evaluation. These interventions can be supported by hydrological modeling by hydrological modeling and can be supported by hydrological modeling to determine the types of NB, scales and locations required to simulate various rainfall landscapes and to reduce floods and depth of water. The modeling process can guide strategic integration of green and blue infrastructure within the existing urban area, adapting flood flexibility without the need for mass redevelopment.

A flooded area in HRBR layout. , Photo Credit: Sudhakar Jain

Many benefits

The benefits of this approach are beyond reducing the risk of floods. Nature-based solutions can support biodiversity, increase groundwater recharge, reduce urban heat, and create opportunities for local employment and community leadership. These co-benefit align closely with the continuous development target 11, which promotes inclusive, safe, flexible and durable cities. However, despite their ability, such intervention is often limited in the scale. Major obstacles include the absence of standardized design framework, limited documentation of long -term impacts and pilot initiatives and a disconnect between the citywide plan or investment decisions.

Waterlogging at the basement trapped the residents in their homes after rain in the silk board quarters in Bangalore. , Photo courtesy: K Bhagya Prakash

A structured and evidence-based implementation strategy is required to address these intervals. Combining with rigid pilots studies, monitoring and evaluation, can generate the display data required to inform the design standards and create confidence among stakeholders. Integrating these findings into the municipal planning structure that are supported by cross-departal coordination and targeted funding, it would be important to move beyond performance projects towards systemic change. Ultimately, the objective is to transition from an older model that tries to quickly dispose of rain water that gives importance to its retention and recession. This change will help the city manage storm water more frequent, while water security and climate will also contribute to flexibility. Knowledge and equipment already exist. The next step is to implement them intentionally and through a collaborative process that brings science, policy and practice together.

Traffic disrupted photo courtesy due to rain on Hosur Road on May 20: K Bhagya Prakash

The city of Bengaluru with careful planning and commitment can lead it to examp how the city can suit its changing water realities. Instead of combating the effects of heavy rainfall only, the city has the opportunity to resume your relationship with water by changing a challenge in a platform for innovation, equity and long -term stability.

Priyanka Jamwal is a senior companion in the program lead (Water and Society Program) and ATRE.

Hymavathi P. Senior Research Associate and Project Manager, Water and Society Program, Atree is the Center for Environment and Development