Key Takeaways

• Since 2013, sponge city construction is promoted as a national climate adaptation strategy in China. Implementation started with the designation of 30 national-level pilot cities in 2015 and 2016. It was then expanded to cities and urban areas across the country and at the provincial level.
• The sponge city is not a single storm water management instrument. Rather, it is intended to draw from a portfolio of measures and strategies that are often characterised as environment-oriented, multi-functional and low-tech. This shall reduce costs as compared to former approaches merely relying on grey infrastructure.
• The sponge city combines individual adaptation measures and technologies developed and promoted internationally under designations such as low-impact development (United States), sustainable urban drainage systems (United Kingdom), blue-green infrastructure (other European countries) and water sensitive urban design (Australia).
• While sponge city measures such as the construction of wetland parks greatly increase liveability in densely populated urban areas, such interventions may raise real estate prices in surrounding residential districts and spur gentrification.
• The main challenges in implementation are administrative and political, e.g. lack of consultation and cooperation across departmental and (sometimes) municipal boundaries.
• In cities with completed sponge city facilities where flooding occurred nonetheless, problems were often traced back to deficiencies in construction and spot-level rather than comprehensive development.