Sponge City Concept

Published on 07 Apr 2025

The "sponge city" is a style of urban development that makes use of "nature-based solutions" to enhance drainage, storage, and water distribution. These remedies included rebuilding wetlands, building new canals and ponds, and using permeable asphalt, all of which would lessen waterlogging and enhance the urban environment.

Significance of Sponge cities

• Flood Mitigation: By absorbing, storing, and slowing down stormwater runoff, green infrastructure—such as permeable pavements, green roofs, rain gardens, and wetlands—helps lower the risk of urban floods during periods of high precipitation.

• Example: The Thames Barrier, located in London, UK, is a flood control structure that keeps storm surges out of the river Thames, protecting the metropolis.

• Climate Resilience: Sponge cities are more robust to higher rainfall brought on by climate change because they are built to respond to shifting weather patterns.

• Example: Green roofs and permeable surfaces are part of Copenhagen, Denmark's sponge city strategy to combat high rainfall and sea level rise.

• Improved water table: By using permeable materials such as permeable pavement and porous concrete, precipitation can seep into the ground rather than accumulating on surfaces.

• Example: Permeable pavement is used in parking lots as part of Melbourne, Australia's Water Sensitive Urban Design concept, which lowers surface runoff.

• Water Quality Improvement: Enhancing the quality of water in urban water bodies and downstream ecosystems is possible with biofiltration systems, retention ponds, and natural or artificial wetlands to filter pollutants, silt, etc.

• Improved Drainage Systems: Improved drainage systems, which more effectively control water flow and avert localized flooding, are frequently found in sponge cities.

• Example: In Wuhan, China, the Sponge City Initiative entails modernizing drainage systems and utilizing sensors to track water levels in real time.

• Urban Greening: The integration of green spaces, vegetated corridors, and natural habitats into urban areas has been shown to improve air quality, regulate temperature, boost biodiversity, and improve ecosystem services.

Challenges of Sponge cities

• High Initial Expenses: Urban areas may need to be developed and retrofitted to become sponge cities, which may include large investments in green spaces, technology, and infrastructure.

• Resistance to Change: Overcoming opposition from stakeholders used to existing systems and traditional urban planning techniques is a challenge.

• Technical Complexity: Due to the complexity in engineering, hydrology, landscape architecture, and urban planning is a challenge for this programme.

• Land Use Constraints: Limited site availability, conflicting land uses, and land ownership difficulties may impede green infrastructure project implementation and limit the scale of Sponge City interventions in densely populated urban areas.

• Maintenance and Operations: Lack of regular maintenance, monitoring, and management are challenges for this programme.

Way Forward

• Integrated Planning and Design: To mainstream Sponge city concepts into city development plans, incorporate water-sensitive design principles into infrastructure projects, urban planning procedures, and development restrictions.

• Innovative Financing Mechanisms: Consider innovative funding options for Sponge City initiatives, such as grants, loans, green bonds, impact investments, and user fees, as well as public-private collaborations.

• Policy Support and Incentives: Implement regulations, tax incentives, development bonuses, and green building standards to encourage the use of Sponge City techniques.

• Knowledge Sharing and Learning: Encourage knowledge sharing, peer-to-peer learning, and best practice exchange amongst cities, regions, and nations to communicate success stories, and new solutions for implementing Sponge City programs.

Tags:
Environment

Keywords:
Sponge city Water conservation Drainage Floods

Syllabus:
General Studies Paper 3

Topics:
Environment and Climate Change