2016年-世界发展银行全球_The_Role_of_Green_Infrastructure_Solutions_in_Urban_Flood_Risk_Management_18页_1mb

Summary of Urban Floods Community of Practice Knowledge Note

Core Content

This knowledge note explores the role of Green Infrastructure (GI) in urban flood risk management. It emphasizes the growing risks of urban flooding due to rapid urbanization, climate change, and environmental degradation. These factors contribute to increased vulnerability, especially among the urban poor who often reside in informal settlements in flood-prone areas.

The note outlines how traditional gray infrastructure (e.g., dams, levees) is being supplemented or replaced by GI solutions. GI includes natural elements such as wetlands, mangroves, green roofs, bioswales, and porous pavements, which use natural processes to manage stormwater runoff, reduce flood risk, and enhance environmental, social, and economic benefits.

Main Points

• Urbanization and Climate Change: These factors are increasing the risk of urban flooding and natural disasters, especially in low-income regions.
• Impact on the Urban Poor: The urban poor are disproportionately affected by floods due to their location in informal settlements.
• Traditional Infrastructure Limitations: Gray infrastructure is not a complete solution, as it can increase flood risk, be costly, and inflexible in the face of climate uncertainties.
• GI as a Complementary Approach: GI works in conjunction with gray infrastructure to provide cost-effective, environmentally friendly, and sustainable flood management.
• Benefits of GI:
  • Economic: GI can be 30% cheaper to build and 25% less costly to maintain than gray infrastructure.
  • Environmental: GI improves water quality, air quality, and groundwater recharge.
  • Social: GI provides recreational spaces, reduces heat island effects, and supports mental well-being.

Key Information

• Global Trends:
  • 90% of new urban residents are in Africa and Asia.
  • By 2050, two-thirds of the world's population will live in urban areas.
  • 70 million people move to urban slums each year, increasing the risk of natural disasters.
• GI Examples:
  • Bioswales: Vegetated channels that slow water flow and filter pollutants.
  • Green Roofs: Vegetated roofs that reduce heat island effects and stormwater runoff.
  • Rain Gardens: Shallow vegetated basins that absorb and filter runoff.
  • Permeable Pavements: Allow infiltration of rainwater into the ground.
  • Mangroves: Provide natural flood barriers and coastal protection.
  • Wetlands: Help absorb excess water and reduce flood risk.
• Case Studies:
  • Vietnam integrates green and gray infrastructure for flexible flood risk management.
  • Singapore has implemented the ABC Waters program, focusing on sustainable stormwater management.
  • United Kingdom has passed the Flood and Water Management Act (2010) to promote GI in urban development.
• Challenges and Recommendations:
  • Impediments to GI implementation include lack of awareness, policy support, and technical know-how.
  • Recommendations include raising awareness, integrating GI with other disciplines, and combining international lessons with local knowledge.
  • International institutions like the World Bank can play a key role in supporting GI adoption and filling knowledge gaps.

Conclusion

GI solutions offer a holistic, sustainable, and cost-effective alternative to traditional flood management approaches. They are especially beneficial for urban poor communities, who face greater risks from natural disasters. By integrating GI into urban planning, cities can enhance resilience, reduce flood damage, and improve quality of life. However, successful implementation requires policy support, community involvement, and technical expertise.