China’s ‘sponge cities’ is an innovative urban planning concept that has been gaining traction in recent years. The idea was proposed by Chinese officials around 2015 and is primarily aimed at resolving the chronic urban flooding problem in Chinese cities. These cities are designed to hold, clean, and then release water to sustain life and development. However, despite the grandeur of this vision, recent flood events raise the question as to why they aren’t stemming the tide of disastrous floods in China.A sponge city absorbs and reuses water much like its biological counterpart. Rather than allowing rainwater to inundate city streets and run off into drains, the sponge city concept focuses on infiltrating, capturing, and utilizing the water. The strategy involves building permeable roads, rooftop gardens, rainwater harvesting systems, and wetlands within the cityscape, which can soak up excess water during rains and store it for future use.However, the drastic and tragic flooding in the summer of 2021 in China, such as what occurred in the city of Zhengzhou, reveals that the sponge city initiative is falling short in the face of extreme weather events. One of the main reasons is that sponge cities are not designed to absorb water from extreme rain events. They can deal only with water from small and medium rain events due to their limited capacity.Furthermore, the problem lies not only in the scale of the rainfall but also in the inadequate implementation of the sponge city concept. While a few cities have enacted initiative measures, some have just made token efforts. As well, obstacles such as poor public participation, lack of technical expertise, and financial constraints also undermine the successful implementation and effectiveness of sponge cities.In conclusion, while the sponge cities concept is an innovative step towards urban resilience and sustainability, it is not a panacea for severe flood issues. It is a longer-term solution and will require continuous investment, public participation, and additional scientific and technical input. As climate change increases the severity and frequency of extreme weather events, China must supplement the sponge cities initiative with other robust and comprehensive flood mitigation measures.
