NbS-29

Sponge City Park & Urban Oxbow

Sponge city parks and urban oxbows integrate green infrastructure to address urban flooding, water quality, and climate resilience.

Technically, they allow absorption and storing of rainwater through permeable surfaces, vegetation, and bioswales, reducing runoff and replenishing groundwater, while urban oxbows (natural or restored meandering river sections) act as water retention and filtration systems addressing riverine flood risks.

These solutions are particularly effective in cities facing rapid urbanization, such as Ho Chi Minh City or Jakarta, where traditional drainage systems are overwhelmed by heavy rains.

Landscape-wise, these NbS create green corridors that enhance urban biodiversity, provide recreational spaces, and improve air quality. They offer community benefits such as flood protection, improved public health through green spaces, and educational opportunities on sustainable urban water management.

Sponge city parks and urban oxbows represent holistic, multifunctional approaches to enhancing the resilience of cities in the face of climate change while improving the quality of life for residents.

LANDSCAPES SUPPORTED

Climate-smart and Resilient City

EbA (ECOSYSTEM-BASED APPROACHES)

  • Water quality improvement
  • Soil erosion control
  • Flood risk mitigation
  • Biodiversity conservation
  • Groundwater recharge
  • Climate regulation

MAIN PROBLEMS ADDRESSED

Biodiversity Loss Biodiversity Loss
Flood Control Flood Control
Disaster Risk Reduction Disaster Risk Reduction
Urban Heat Island Urban Heat Island

EbA (ECOSYSTEM-BASED APPROACHES)

SUPPORTING

  • Biodiversity Habitat: Provide habitats for wildlife, fostering urban biodiversity in both plant and animal species.

REGULATING

  • Flood Regulation: Absorb and store rainwater, reducing surface runoff and mitigating urban flooding.

PROVISIONING

  • Water Quality Enhancement: Filter pollutants and sediments from stormwater, improving water quality for downstream ecosystems.

SOCIAL BENEFITS

  • Recreation and Well-being: Offer green spaces for leisure, physical activity, and social interaction, enhancing public health and community well-being.
NbS29_Dry Season_Recreational Park mitigating Urban Heat Stress
NbS29_Heavy Rain_Park with High capacity of water retention

PROJECT’S CHALLENGES & RISKS

Limited Space in Dense Urban Areas: Finding available land for sponge city parks can be challenging due to high competition for space.

Maintenance Complexity: These projects require ongoing maintenance of green infrastructure and water management systems, which can be difficult to sustain.

Funding Constraints: Securing sufficient funding for the initial setup and long-term upkeep of these infrastructure projects can be a barrier, especially in developing urban areas with competing priorities.

NbS co-BENEFITS AND THEIR INDICATORS

Flood Mitigation

Reduction in peak flood discharge and stormwater runoff volumes during cloudbursts.

Water Quality Improvement

Decrease in concentrations of pollutants in river water after passing through the park.

Biodiversity Enhancement

Increase in the number of aquatic and terrestrial species observed in and around the park area.

Urban Heat Island Mitigation

Measurable reduction in ambient temperature in areas within and around the sponge city park.

Carbon Sequestration

Amount of CO2 captured and stored in the soil, measured through biomass growth and soil carbon content.

Recreational and Aesthetic Value

Increased number of visitors and positive community feedback on the use of the park for leisure.

COST ANALYSIS

Direct costs

Initial construction costs : $200k to $500k/ha, covering land preparation, vegetation, water management systems, and infrastructure.

Indirect costs

Time Horizons and Discount Rate

Average lifespan of 20–30 years, with a discount rate of 3–7%.

Direct Benefits

Annual savings of $30k to $70k per ha in avoided damages and treatment costs.

Indirect Benefits

Urban cooling and biodiversity enhancement can provide $10k to $20k/ha/year.

Risk Assessment

Risk factors such as flooding or ecosystem degradation could incur $10k to $30k per ha for repairs and adaptive measures.

REFERENCES

Singapore, Bishan-Ang Mo Kio Park.

Malaysia,Kuala Lumpur, River of Life Project.

Vietnam, Hanoi’s Red River Parks.

China, Suzhou Creek Sponge City Project.

 

IMPLEMENTATION OPPORTUNITIES

Indonesia, Jakarta’s riverbanks of Ciliwung River.

Vietnam, HCMC’s riverside parks along Saigon River.

Philippines, Manila, Pasig River agglomeration.

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