Syllabus: GS1/Urbanisation and related challenges
Context
- Bengaluru rain has led to widespread waterlogging, severe damages and traffic disruptions.
- Environmentalists and water conservationists have flagged the poor status of the city’s current drainage system, which is outdated and ill-equipped to handle the city’s current population and rainfall intensity.
What are Floods?
- Floods are the most frequent type of natural disaster and occur when an overflow of water submerges land that is usually dry.
Types of Floods
- Flash floods are caused by rapid and excessive rainfall that raises water heights quickly, and rivers, streams, channels or roads may be overtaken.
- River floods are caused when consistent rain or snow melt forces a river to exceed capacity.
- Coastal floods are caused by storm surges associated with tropical cyclones and tsunamis.
- Urban flooding occurs as a result of land development. Permeable soil layers are being replaced by impermeable paved surfaces, through which water cannot infiltrate.
- This leads to greater runoff being generated, which can make rivers out of roadways and ponds out of car parks.
Causes of Urban Flooding
- Heavy or intense rainfall in a short period.
- Blocked or undersized drainage systems.
- Encroachment of natural drains, lakes, or wetlands.
- Loss of green cover, leading to reduced water absorption.
- Rapid urbanization without proper planning or zoning regulations.
- Outdated infrastructure that can’t handle current population or rainfall levels.
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.
Government Initiatives
- 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 developing basic urban infrastructure in cities and towns, particularly in the areas of water supply, sewerage and septage management, and stormwater 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.
| Global Models Related to Mitigating Urban Flooding – Singapore, a global leader in managing urban flooding despite its high rainfall and dense urban environment. – China – “Sponge Cities” Initiative 1. Challenge: Urban flooding due to rapid city expansion and impermeable surfaces. 2. Solution: Cities designed to absorb and reuse rainwater like sponges. – United States – New York City (Post-Hurricane Sandy) 1. Challenge: Severe coastal flooding from hurricanes and storm surges. 2. Solution: The “Big U” project in Manhattan. 3. Raised parks, floodwalls, berms, and green infrastructure wrapping around the city. 4. Multi-functional public spaces that act as flood barriers. – Japan – Tokyo’s Underground Floodwater System 1. Challenge: Flooding from typhoons and river overflows in a dense urban area. 2. Solution: Built the world’s largest underground flood diversion system. |
Conclusion
- Combining engineering solutions, smart urban planning, real-time technologies, and community participation is key to building flood-resilient cities and effectively mitigating the challenge of urban flooding in India.
Source: IE
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