Resilient Economies Strategies for Sinking Cities and Flood Risks 2025

–Control zones and construction materials: The regulation implemented a zoning- based risk classification system, requiring geotechnical assessments, continuous monitoring and tailored foundation methods for new developments. High-risk areas were required to use lightweight, high-strength materials and deep-pile foundations, directly linking construction practices to subsidence management. –Monitoring and collaboration: Land subsidence and groundwater detection networks were established, providing critical data to understand, evaluate and supervise groundwater extraction and construction activities. Additionally, formalized cross-department collaboration ensures coordinated action, for instance, related to planning, water management and construction. –Nature-based infrastructure: Since 2016, Shanghai has participated in China’s “sponge city” programme, integrating green infrastructure, water conservancy and technological upgrades to restore natural water cycles. Solutions, such as green roofs, permeable pavements, rain gardens and constructed wetlands, collectively absorb and reuse stormwater, reduce flood risks and support groundwater recharge.115 Sixteen districts have renovated spaces into sponge parks. Notable examples include the 54-hectare Starry Sky Park in Lingang, which filters and redirects stormwater into natural channels, a rainwater garden in Nanhui New City, and conservation green spaces with water permeable bricks in Rainbow Bay Park, Hongkou District.116Takeaways According to the International Journal of Environmental Research and Public Health, Shanghai’s average annual subsidence rate has dropped to 5mm. While localized uneven sinking persists, the city’s overall approach offers learning opportunities and a model for urban leaders seeking to build resilience against land subsidence and related risks. –Decisive prioritization: Shanghai’s progress reflects the importance of recognizing land subsidence as a significant threat and acting proactively to address it before further or catastrophic damage occurs. –Integrated planning: The city’s progress was not achieved through isolated measures but through the convergence of regulation, infrastructure investment and active monitoring, demonstrating the value of multistakeholder action. –Systems approach: Shanghai stands out as a city that has recognized the impacts of urbanization on land and water. The city’s journey highlights that addressing subsidence requires broader consideration of urban development, local soil conditions and climate pressures. Such an approach can enable the movement towards systems thinking for building resilience. Shanghai’s journey highlights that addressing subsidence requires broader consideration of urban development, local soil conditions and climate pressures. Resilient Economies: Strategies for Sinking Cities and Flood Risks 22