"Kerala floods expose how sedimentation and wetland loss amplify disaster risk"
Carrying capacity of rivers
a river's ability to convey water without overflowing, reduced by sedimentation
Sedimentation
accumulation of silt/sand in riverbeds and reservoirs, reducing water-holding capacity
India's flood disasters are rarely the product of rainfall alone. They are co-produced by ecological degradation, altered land use, and governance failures that systematically erode natural buffers. The Disaster Management Act, 2005 established a three-tier institutional structure — the National Disaster Management Authority (NDMA) at the apex, State Disaster Management Authorities (SDMAs), and District Disaster Management Authorities (DDMAs) — with a mandate that explicitly includes risk reduction, not merely post-event relief. India is also a signatory to the Sendai Framework for Disaster Risk Reduction 2015–2030, whose four priority areas include understanding disaster risk, strengthening governance, investing in resilience, and enhancing preparedness for effective response.
Kerala sits at the intersection of two of India's most ecologically sensitive zones: the Western Ghats and a dense coastal-riverine network. The Western Ghats Ecology Expert Panel (WGEEP), popularly known as the Gadgil Committee, recommended that large portions of the Western Ghats be designated Ecologically Sensitive Areas (ESAs) with strict curbs on quarrying, mining, and construction. These recommendations have faced sustained political resistance from the states concerned — a tension that lies at the heart of recurring disaster vulnerability in the region. The catastrophic floods of 2018 served as a warning that was not fully heeded: they deposited enormous sediment loads into rivers and reservoirs, setting the stage for compounding vulnerability in subsequent years.
The concept of carrying capacity of rivers is central to understanding Kerala's flood crisis. A river's carrying capacity — its ability to convey a given volume of water without overflowing — is determined not just by channel width but by channel depth, which is progressively reduced by sedimentation. Silt and sand accumulate naturally, but the rate is dramatically accelerated by upstream deforestation, landslides in hilly terrain, and the legacy of past flood events. The 2018 Kerala floods deposited massive sediment loads across the river network; without systematic desilting, this legacy directly reduces the headroom available during subsequent high-rainfall events.
Reservoirs face the same problem. A CAG report found significant storage-capacity losses in Kerala's dams due to sedimentation — the Kallarkutty dam had lost 47% of gross storage capacity over 45 years, while the Anayirankal dam had lost 30.92% in 33 years. …
Which of the following Protected Areas are located in Cauvery basin?
1.Nagarhole National Park
2.Papikonda National Park
3.Sathyamangalam Tiger Reserve
4.Wayanad Wildlife Sanctuary
Select the correct answer using the code given below:
With reference to Kerala's flood vulnerability, consider the following statements:
1.The Kallarkutty dam lost nearly half its gross storage capacity over four decades due to sedimentation.
2.Kerala's paddy cultivation area has declined by more than 70% since the late 1970s.
3.The Disaster Management Act, 2005 mandates only post-disaster relief and does not cover pre-disaster risk reduction.
Which of the statements given above is/are correct?
Which of the following best explains why impervious surfaces such as tarred roads and concrete pavements worsen flash flooding in Kerala?
The Western Ghats Ecology Expert Panel (WGEEP), also known as the Gadgil Committee, primarily recommended which of the following?
Assertion (A): A single extreme rainfall event can cause more severe flooding in a river system that experienced major floods a few years earlier than in one that did not.
Reason (R): Previous flood events deposit large volumes of sediment in riverbeds and reservoirs, reducing their water-carrying and storage capacity for subsequent events.
Want the full note, Prelims Facts & MCQ answers?
Create a free account — takes less than a minute.
Create free account