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.
Approach · directive: “discussing / highlight”
What it asks · Explain why cities are flooding more often after intense rain, then set out the preparedness measures that reduce loss of life and property.
The question has 2 parts — answer each
- Discuss: the reasons for the increasing frequency of urban floods
- Highlight: the preparedness mechanisms to reduce risk during such events
Open with · Cities such as Mumbai in 2005 and Chennai in 2015 showed that heavy rain turns into a disaster when drains, lakes and floodplains are lost to construction.
Cover
- Natural causes: more intense short-duration rain linked to climate change, the urban heat island effect, cyclones and storm surge in coastal cities, and high tides blocking outfalls.
- Land use: encroachment on lakes, wetlands, floodplains and drains, and paved surfaces that cut infiltration and speed up run-off.
- Infrastructure: drains designed for low rainfall, silted, clogged with waste or missing, weak maintenance, and sudden dam or reservoir releases upstream.
- Governance: multiple agencies working separately, weak enforcement of building norms and master plans, and no local flood-risk mapping.
- Preparedness, forecasting: flood-risk mapping and zoning, Doppler radar and rain-gauge networks, IMD nowcasts and warnings, and a coordination protocol with dam operators.
- Preparedness, systems: drainage master plans, drain desilting before monsoon, restoration of lakes and wetlands, and green measures such as rain gardens, permeable pavements and harvesting.
- Preparedness, response: early warning to citizens, control rooms, SOPs with trained response forces, shelters, evacuation routes, insurance and public education, as NDMA's 2010 urban flooding guidelines urge.
Close with · Making room for water through restored wetlands, better drains and land-use control, backed by early warning, is the surest way to cut urban flood risk.
Question: UPSC's CS (Main) 2016, GS Paper III — paper ↗. Approach: Minimalist IAS, checked 30 Sept 2026 (how we verify) — UPSC publishes no model answers. ·
Model answer · 303 words (UPSC limit 200) · Minimalist IAS
Mumbai in 2005 and Chennai in 2015 showed that heavy rain becomes a disaster when a city builds over its drains, lakes and floodplains; NDMA's 2010 guidelines treat urban flooding as a distinct hazard.
Reasons for urban floods
- Climate: more intense short-duration rainfall, convective downpours over the urban heat island, and in coastal cities storm surge and high tides that block outfalls.
- Land use: encroachment on lakes, wetlands, floodplains and natural drains, and paved surfaces that stop infiltration and speed run-off.
- Drainage: storm drains built for low rainfall, silted, clogged with waste, mixed with sewage and rarely maintained.
- Upstream releases: sudden discharge from reservoirs without warning downstream, as in Chennai in 2015.
- Governance: many agencies with no single flood authority, weak enforcement of master plans and building norms, and no local flood-risk maps.
Preparedness mechanisms
- Know the risk: ward-level flood hazard mapping and zoning, Doppler weather radars and dense automatic rain gauges, and IMD nowcasts turned into city-specific warnings.
- Protocols: reservoir operation rules with advance warning before releases, a single nodal authority for urban floods, and an incident response system fixing who does what.
- Drains and water bodies: drainage master plans using updated rainfall data, pre-monsoon desilting, separation of sewage from storm water, and restoration of lakes and wetlands.
- Sponge measures: rain gardens, permeable pavements, rainwater harvesting and protected green spaces that make room for water.
- Response readiness: early warning by SMS and media, control rooms, standard operating procedures, trained municipal and SDRF/NDRF teams, pumps, identified shelters and evacuation routes, and protection of hospitals and power supply.
- Community and finance: ward volunteers, mock drills, public education and flood insurance, with enforcement action after every event.
Making room for water through restored wetlands, better drains and land-use control, backed by early warning and trained responders, is the surest way to cut urban flood risk.
Written by Minimalist IAS from facts checked at source (how we verify) — a little fuller than exam length, so every part of the question is covered; in the hall, keep the structure and trim the detail. UPSC publishes no model answers: compare your structure and coverage with this, then write your own.