Subject: Disaster Management

Urban flooding has emerged as a critical climate-induced disaster, with IPE Global and Esri India forecasting a 43% increase in extreme rainfall events by 2030 in India, necessitating urgent attention and comprehensive management strategies.

Causes of Urban Flooding in India

• Intense, short-burst rainfall driven by a warming atmosphere increases hourly rain rates, overwhelming drains and nullahs.

• Unplanned urbanisation: concretisation, loss of wetlands and lake networks (e.g., Bengaluru has lost ≈80% of its lakes) sharply lowers infiltration and raises runoff.

• Encroachment of natural channels and flood-plains blocks flow paths; illegal structures sit atop storm-water drains in many cities.

• Ageing / undersized drainage—Mumbai’s Victorian system was designed for 25 mm h⁻¹ but now faces >100 mm h⁻¹ events.

• Solid-waste choking; plastics and silt clog inlets, reducing hydraulic capacity.

• Topographic factors: many metros lie in low-lying coastal or river-plain terrain (Mumbai, Kolkata, Chennai), or in saucer-shaped basins (Bengaluru) that naturally pond water.

• Back-water effects from high tides or sudden dam releases compound rainfall runoff (Mumbai, Hyderabad, Surat).

Two Major Urban Floods

Indian Policies & Frameworks

• NDMA Guidelines on Management of Urban Flooding (2010): treat urban flooding as a distinct hazard; mandate city-level flood cells, real-time hydro-meteorological networks, and micro-zonation of drainage basins.

• Standard Operating Procedure for Urban Flooding (2017, MoHUA): lays out pre-monsoon preparedness, early-warning, Emergency Operations Centres and post-flood restoration protocols.

• Model Building Bye-Laws 2016 & URDPFI Guidelines 2014: integrate rain-water harvesting, minimum open-space ratios, and prohibitions on flood-plain construction.

• Storm-Water Drainage Manual 2019 (MoHUA): design standards for Sustainable Urban Drainage Systems (SUDS), permeable pavements and detention basins.

• AMRUT & AMRUT 2.0: finance storm-water projects; 750 works completed eliminating 3,445 water-logging points.

• 15th Finance Commission Urban Flood Mitigation Fund (₹2,500 cr): dedicated support for integrated projects in seven flood-prone metros, starting with Chennai basin (₹500 cr central share).

• Smart Cities & Climate-Resilient Cities missions: promote “sponge city” pilots, lake rejuvenation and early-warning apps.

• National Flood Management Guidelines (2008) complement urban focus with basin-wide measures and reservoir rule-curves.

Together these instruments aim to shift cities from ad-hoc response to risk-informed planning, resilient infrastructure and community preparedness, curbing the growing menace of climate-induced urban floods.