Bengaluru Urban Flooding
Kartavya Desk Staff
Syllabus: Disaster Management
Source: TOI
Context: Bengaluru witnessed over 130 mm rainfall in just 12 hours, leading to severe urban flooding that left 3 dead, 500 homes inundated, and major roads, underpasses, and lakes overwhelmed.
About Bengaluru Urban Flooding:
What is Urban Flooding?
• Urban flooding refers to the overflow of water in densely built environments due to poor drainage and excessive rainfall.
• Unlike rural floods, it occurs rapidly and overwhelms infrastructure—seen in cities like Mumbai (2005), Chennai (2015), and Hyderabad (2020).
Causes of Urban Flooding in Bengaluru:
• Natural Causes:
• Heavy Monsoon Rains: South-west monsoon causes intense rainfall; July averages often exceed 100 mm in a day. Topography: The city sits on an undulating terrain with natural low-lying basins like Hebbal, Koramangala-Challaghatta valleys.
• Heavy Monsoon Rains: South-west monsoon causes intense rainfall; July averages often exceed 100 mm in a day.
• Topography: The city sits on an undulating terrain with natural low-lying basins like Hebbal, Koramangala-Challaghatta valleys.
• Man-made Causes:
• Encroachment of Lakes & Wetlands: Bengaluru has lost 79% of its water bodies in the last 40 years (IISc data). Poor Drainage Maintenance: Rajakaluves (storm drains) are choked, buried, or encroached, reducing water-carrying capacity. Outdated City Plans: CDP and zoning regulations have not evolved with urban density and climate risks. Unregulated Construction: Tech parks and apartments are often built over floodplains, violating environmental norms. Lack of Coordination: Civic bodies function in silos, delaying response and long-term planning.
• Encroachment of Lakes & Wetlands: Bengaluru has lost 79% of its water bodies in the last 40 years (IISc data).
• Poor Drainage Maintenance: Rajakaluves (storm drains) are choked, buried, or encroached, reducing water-carrying capacity.
• Outdated City Plans: CDP and zoning regulations have not evolved with urban density and climate risks.
• Unregulated Construction: Tech parks and apartments are often built over floodplains, violating environmental norms.
• Lack of Coordination: Civic bodies function in silos, delaying response and long-term planning.
Impacts of Urban Flooding:
• Loss of Life & Property: Monsoon 2025 led to 3 deaths and submerged areas like Koramangala, Bellandur, and ORR.
• Economic Disruptions: IT corridor shutdowns cost crores; flooding impacts India’s $194B tech exports sector.
• Public Health Crisis: Waterlogging spreads vector-borne diseases and contamination-related infections.
• Transport & Power Outages: Prolonged disruption of metro, roads, and electrical systems during peak rains.
Global Best Practices:
• Singapore’s SWAN System: Smart sensors detect water level rise and activate flood alerts in real-time.
• Netherlands’ “Room for the River”: Managed retreat and river expansion reduce flood pressure in cities.
• China’s “Sponge Cities“: Permeable pavements, green roofs, and wetlands absorb excess water sustainably.
• FLOAT House (New Orleans): Floating homes adapt to changing water levels, minimizing displacement.
Way Forward:
• Restore Natural Drainage: Reconnect lakes, wetlands, and rajakaluves following IISc & NDMA recommendations.
• Regular Desilting: Institutionalize desilting of secondary/tertiary drains before monsoons, with third-party audits.
• Urban Planning Reform: Revise Bengaluru’s CDP to include flood zoning and green infrastructure mandates.
• Smart Flood Management: Use IoT-based water monitoring systems and integrate early warning dashboards.
• Clear Political Accountability: Strengthen BBMP’s autonomy and conduct regular audits to fix administrative gaps.
Conclusion:
Bengaluru’s repeated flooding is no longer a seasonal mishap but a governance failure. Restoring ecological wisdom and enforcing climate-resilient urban planning is not optional—it is a necessity. A city of lakes must not become a city under water.
• The frequency of urban floods due to high intensity rainfall is increasing over the years. Discussing the reasons for urban floods, highlight the mechanisms for preparedness to reduce the risk during such events. (UPSC-2016)