Background
Kerala receives heavy rainfall from the Southwest Monsoon and has 44 west-flowing rivers originating in the Western Ghats.
Traditionally, wetlands, paddy fields, forests, and floodplains acted as natural sponges, storing excess rainwater and reducing flood peaks.
Over the past few decades, rapid urbanisation, wetland reclamation, river siltation, and infrastructure expansion have significantly altered the state's natural drainage system.
As a result, even moderate to heavy rainfall now leads to severe flooding in many regions.
What is driving the flood intensity?
River siltation: Sediment buildup reduces the carrying capacity of rivers.
Dam storage loss: The extremely heavy rains have increased the water level in all dams, run by both the state electricity board and the irrigation department. A Comptroller and Auditor General (CAG) audit found major storage loss at reservoirs due to sedimentation, including 47% at Kallarkutty.
Wetland shrinkage: Paddy and wetland area fell from 7.93 lakh hectares in 1979 to 1980 to 1.80 lakh in 2023 to 2024.
Concretisation: Hard surfaces from urbanisation alter natural drainage. During heavy rains, these impervious surfaces channel stormwater rapidly into nearby rivers and streams, causing water levels to rise within hours.
Why do these factors worsen floods?
Reduced buffer: Lost wetlands and paddy no longer absorb excess water. Paddy fields, marshlands and wetlands are known for absorbing a huge volume of rainfall.
Faster runoff: Concrete surfaces speed runoff into swollen rivers.
Lower channel capacity: Silted rivers overflow at lower volumes.
State Government's Response
Desilting
Planned desilting of rivers and reservoirs to improve storage and river flow.
Asset Register
Preparation of an asset register for rivers, streams, and lakes.
Land auditing to identify and prevent encroachments.
Wetland and Paddy Restoration
Restoration of paddy fields and wetlands to revive natural flood buffers.
Improved Land-use Planning
Measures to regulate construction in ecologically sensitive and flood-prone areas.
Challenges
Climate Change
Increasing frequency of extreme rainfall events.
Wetland Encroachment
Continued conversion of wetlands for urban and commercial development.
Reservoir Sedimentation
Ongoing sediment accumulation reduces storage capacity.
Unplanned Urbanisation
Expansion of impervious surfaces worsens runoff.
Weak Enforcement
Inadequate implementation of land-use and environmental regulations.
Balancing Development and Conservation
Meeting infrastructure needs while protecting fragile ecosystems.
Way Forward
Restore Natural Ecosystems
Protect and restore wetlands, floodplains, and paddy fields.
Scientific River Management
Undertake periodic desilting based on hydrological assessments.
Sustainable Urban Planning
Promote permeable pavements, green infrastructure, and rainwater harvesting.
Strengthen Land-use Regulations
Prevent encroachment of rivers, wetlands, and floodplains.
Integrated River Basin Management
Coordinate management of rivers, reservoirs, forests, and urban drainage systems.
Climate-Resilient Infrastructure
Improve flood forecasting, drainage networks, and reservoir operations.
Community Participation
Encourage local communities in wetland conservation and disaster preparedness.
Conclusion
Floods that are happening in Kerala are becoming more frequent due to changes in the region’s hydrological cycle, owing to siltation of rivers, wetland degradation, sedimentation of reservoirs, and uncontrolled urbanisation, along with the rains during the monsoon season.
