Q. Flooding in urban areas is an emerging climate-induced disaster. Discuss the causes of this disaster. Mention the features of two such major floods in the last two decades in India. Describe the policies and frameworks in India that aim at tackling such floods.

Model Answer:

Urban flooding is a severe, recurring disaster where high-intensity rainfall overwhelms city drainage systems, exacerbated by unplanned urbanization and changing climate extremes.

1. Causes of Urban Flooding

• Climate-Induced Extremes: Increased frequency of high-intensity, short-duration micro-climatic rainfall and coastal sea-level rise (IPCC AR6).
• Ecological Encroachment: Construction over natural wetlands, floodplains, and lakes, destroying natural water sinks (Pallikaranai marsh, Chennai).
• Impervious Surfaces: Widespread concreting and asphalt reduce groundwater percolation, rapidly increasing surface run-off.
• Obsolete Drainage Infrastructure: Antiquated storm-water drains designed for lower rainfall intensities.
• Solid Waste Mismanagement: Unsegregated garbage and plastic waste choking urban drainage channels (Mithi River, Mumbai).

2. Features of Two Major Floods (Last Two Decades)

1. Mumbai Floods (2005):
   • Trigger: Extreme climatic event (944 mm rainfall in 24 hours).
   • Aggravators: Severe encroachment of the Mithi River; choked centuries-old storm-water drains.
   • Impact: Total collapse of the financial capital’s transport, power, and communication infrastructure.
2. Chennai Floods (2015):
   • Trigger: Unprecedented North-East monsoon downpours combined with sudden discharge from the Chembarambakkam reservoir.
   • Aggravators: Haphazard IT corridor development over natural floodplains and rapid decimation of interconnected temple tanks.
   • Impact: Massive human displacement, submerged airport, and industrial supply-chain paralysis.

3. Tackling Policies and Frameworks in India

• NDMA Guidelines on Urban Flooding (2010): Delinks urban flooding from riverine flooding, mandating specialized Early Warning Systems (e.g., I-FLOWS in Mumbai, C-FLOWS in Chennai).
• Disaster Management Act 2005: Empowers State and District Disaster Management Authorities (SDMA/DDMA) to enforce localized monsoon-preparedness and response plans.
• MoHUA Frameworks: The Standard Operating Procedures (SOP) and Manual on Storm Water Drainage Systems mandate pre-monsoon desilting and municipal accountability.
• Urban Infrastructure Missions: AMRUT and the Smart Cities Mission prioritize funding for upgrading drainage networks, water body rejuvenation, and integrating “Sponge City” concepts (permeable pavements, rainwater harvesting).

Building climate-resilient cities requires shifting from reactive disaster response to proactive risk reduction through eco-sensitive urban planning, strict anti-encroachment laws, and localized watershed management.