The concept of "sponge cities" has gained prominence since it was introduced by Chinese landscape architect Kongjian Yu, founder of Turenscape, and was officially adopted as a national policy in China in 2013 to combat urban flooding. This approach prioritizes nature-based infrastructure such as wetlands, rain gardens, and permeable pavements, creating landscapes with porous soil where native plants can thrive with minimal maintenance. When it rains, these systems absorb and slow down water flow, reducing flood risks. In contrast, traditional concrete- and pipe-based drainage solutions, though widely used, are costly, rigid, and require frequent maintenance, sometimes even making cities more vulnerable to flooding due to blockages and overflows.
Additionally, sponge city strategies have proven to be more cost-effective. For example, the program in Wuhan saved over 4 billion yuan ($550 million) compared to conventional concrete-based alternatives, according to a policy brief by the University of Leeds. By integrating ecological systems into urban landscapes, sponge cities offer an adaptable and economically viable approach to water management. This round up organizes sponge city projects based on their primary hydrological function, recognizing that different strategies play complementary roles in mitigating urban flooding and enhancing water resilience. While many projects incorporate multiple functions, this article highlights their dominant contributions to water-sensitive urban design.
