The frequency of urban floods due to high-intensity rainfall is increasing over the years. Discuss the reasons for urban floods, highlighting the mechanisms for preparedness to reduce the risk during such events.

Introduction: Urban flooding is the inundation of built-up land when high-intensity rain outpaces the drainage capacity of a developed catchment. Concrete surfaces make runoff peak fast and high, so cities flood within hours — a pattern the NDMA's 2010 urban-flooding guidelines were written to address. You can read more in our note on urban flooding in India.

Reasons for urban floods:

• Climatic: the urban heat-island effect and a changing climate concentrate rain into short, very intense bursts, including cloudburst-like spells.
• Hydrological: encroachment on lakes, wetlands and natural drains, and the loss of permeable soil to concrete, sharply shrinks infiltration and storage.
• Governance: stormwater drains designed for only 12–20 mm/hour rainfall, poor pre-monsoon desilting, unplanned outward growth and fragmented, overlapping civic agencies.

Preparedness mechanisms:

• Watershed- and ward-level stormwater drainage inventories, with the catchment as the basis for design.
• Pre-monsoon desilting of all major drains completed by 31 March each year.
• Real-time hydro-meteorological early warning through the Central Water Commission network, Doppler radar nowcasting, and a dedicated Urban Flooding cell in city plans.
• Mandatory rooftop rainwater harvesting, rain gardens in public parks, and active protection of urban water bodies.

Conclusion: A sponge-city approach — sustainable urban drainage, restored wetlands and lakes, and building codes that make every plot absorb rather than shed water — is the durable way to cut urban-flood risk and protect lives and assets.