Reimagining Urban Infrastructure for Flood Resilience

Syllabus: GS2/Governance, GS3/Environment, GS3/Disaster Management

Context

• The heavy rainfall in Mumbai has once again exposed the vulnerability of Indian cities to urban flooding, highlighting the need to redesign urban infrastructure to absorb rainwater in a climate-resilient manner.

What is Urban Flooding?

• Urban flooding is defined as a frequent phenomenon in urban areas where water runoff from impermeable surfaces, such as concrete structures, leads to flooding, particularly during prolonged rainfall. 
• This type of flooding is exacerbated by rapid urban development, poor flood management, and encroachment onto flood-prone areas.

Why Are Indian Cities Vulnerable to Urban Flooding?

• Disrupted Hydrological Systems: The urban expansion has disrupted natural hydrological networks like rivers, creeks, wetlands, lakes, salt pans, and floodplains that traditionally absorbed rainwater.
• Loss of Permeable Surfaces: The replacement of open spaces and soil with concrete roads, pavements, and buildings has reduced groundwater recharge and increased surface runoff.
• Drainage Systems: Many Indian cities are dependent on conventional storm-water drainage systems that are inadequate to handle short-duration but high-intensity rainfall events associated with climate change.
  • In Mumbai, the drainage network largely relies on gravity to discharge water into the sea. 
• Climate Change: Rising global temperatures have increased the frequency and intensity of extreme rainfall events, making urban flooding more frequent even in cities with improved drainage infrastructure.

Solutions to Mitigate Urban Flooding

• Upgrading and maintaining stormwater drainage infrastructure.
• Protecting and restoring wetlands, lakes, and natural waterways.
• Promoting green infrastructure: rain gardens, green roofs, permeable pavements.
• Implementing urban planning policies to prevent construction on flood-prone areas.
• Rainwater harvesting and better solid waste management.

Steps taken by India

• Swachh Bharat Mission (Urban): While primarily focused on sanitation, this mission also emphasizes solid waste management and pollution control, which contribute to preventing waterlogging and flooding.
• National Smart Cities Mission: It promotes the measures to manage urban flooding through rainwater harvesting, green spaces and proper drainage system.
• Atal Mission for Rejuvenation and Urban Transformation (AMRUT):The Mission focuses on development of basic infrastructure, in the cities and towns, in the sectors of water supply; sewerage and septage management; storm water drainage.
• Guidelines and Regulations: The government has issued guidelines for sustainable urban development, encouraging the incorporation of features like permeable pavements, green roofs, and retention ponds to enhance water absorption.
• The Ministry of Housing & Urban Affairs (MoHUA) has formulated Model Building Bye Laws (MBBL), 2016 for the States/UTs.
  • As per MBBL, all buildings having a plot size of 100 sq.m. or more shall mandatorily include the complete proposal of rainwater harvesting.
• The National Water Policy (2012) advocates that the conservation of rivers, river corridors, water bodies and infrastructure should be undertaken in a scientifically planned manner through community participation.
• Jal Shakti Abhiyan: It aims to harvest the monsoon rainfall through creation of artificial recharge structures, watershed management, recharge and reuse structures, intensive afforestation and awareness generation.
• MoHUA has issued Standard Operating Procedures (SoPs) on Urban Flooding in 2017 and published manual on Storm Water Drainage Systems, 2019 to assist the States/ Union Territories (UTs), Urban Local Bodies (ULBs) and other stakeholders

Global Best Practices Related to Mitigating Urban Flooding

• China’s Sponge City Policy: Following the devastating Beijing floods of 2012, China adopted the Sponge City approach to improve the water retention capacity of urban areas.
• The Netherlands’ Blue-Green Infrastructure: It is an integrated network of natural and engineered systems that manage rainwater while improving urban resilience and environmental quality.
• Singapore, a global leader in managing urban flooding despite its high rainfall and dense urban environment.

Challenges Before Indian Cities

• Continued encroachment upon wetlands, lakes, and floodplains.
• Unplanned urbanisation and extensive concretisation.
• Limited adoption of nature-based solutions in urban planning.
• Fragmented institutional responsibilities for water and land management.

Way Ahead

• Integrating natural ecosystems with urban planning is necessary for a sustainable and climate-resilient approach to flood management.
• Combine engineering solutions, smart planning, real-time tech, and community involvement to build flood-resilient cities will mitigate the concern of Urban Flooding in India.

Source: IE