Cities across the world are grappling with the escalating challenges of urban flooding and climate resilience. Traditional grey infrastructure such as concrete flood channels, drainage pipes, and embankments often proves insufficient in the face of extreme weather events.
Enter the Sponge City Concept, a nature-based approach that prioritises water absorption and ecological restoration to mitigate flooding and enhance urban resilience. Developed by renowned landscape architect Kongjian Yu, the Sponge City model is now influencing urban planning strategies worldwide.
How the Sponge City Concept Works
The fundamental idea behind a Sponge City is simple: work with nature, not against it. Instead of channelling rainwater away as quickly as possible, this approach focuses on capturing, slowing, and utilising water through ecological design. The Sponge City concept is built on three core principles. First, retaining water at its source by incorporating features such as green roofs, permeable pavements, and rain gardens. These measures allow water to seep into the ground rather than overwhelming drainage systems. Second, slowing down water flow through the use of constructed wetlands, bioswales, and naturalised riverbanks, which help control water movement and reduce the risk of sudden, destructive floods. Finally, embracing water in low-lying areas by transforming flood-prone spaces into parks, lakes, and urban wetlands, turning a vulnerability into an asset.
This approach not only alleviates flood risks but also improves biodiversity, air quality, and urban aesthetics. Moreover, by replenishing groundwater and reducing heat island effects, Sponge Cities contribute to broader climate adaptation efforts.
Where the Sponge City Concept is Being Applied
Kongjian Yu’s vision has gained significant traction, particularly in China, where the government formally adopted the Sponge City Programme in 2013. Several cities have since implemented large-scale projects demonstrating the effectiveness of the model.
One notable example is Qunli Stormwater Park in Harbin, China. This project transformed a flood-prone area into an ecological park that absorbs and filters rainwater naturally. By incorporating wetlands and native vegetation, the park prevents urban flooding while providing a green space for residents. In Sanya City, Hainan, a tropical coastal region, Yu’s team developed rain gardens, bio-retention basins, and urban wetlands to handle monsoon rainfall sustainably. Another significant project is Lingang Bird Airport in Shanghai, where an artificial wetland system was designed to manage stormwater while providing a sanctuary for migratory birds, showcasing the intersection of urban resilience and biodiversity conservation.
Beyond China, the Sponge City concept is being explored in cities worldwide. Rotterdam in the Netherlands, with its long history of managing water, has integrated similar principles into its urban planning. Initiatives such as water plazas—public squares that double as rainwater storage areas—demonstrate how cities can turn flooding risks into multifunctional urban spaces. In the United States, New York City has begun implementing green infrastructure projects, such as permeable pavements and green roofs, to reduce stormwater runoff and combat flooding. In the UK, London is incorporating sustainable drainage systems (SuDS) inspired by the Sponge City concept into urban developments to improve flood resilience while enhancing biodiversity.
Kongjian Yu: The Man Behind the Vision
Born in 1963 in Dongyu Village, Zhejiang Province, China, Kongjian Yu grew up in a rural farming community, where his connection to nature shaped his future work. A defining moment in his childhood came when the local use of DDT pesticides in 1972 led to the death of fish in a nearby creek. Witnessing this environmental disaster firsthand sparked his awareness of human impact on ecosystems.
Yu initially studied ornamental gardening at Beijing Forestry University, but his academic path took a transformative turn when he pursued a master’s and doctorate at Harvard University. There, he focused on landscape ecological planning, refining his ideas on how urban spaces could coexist harmoniously with natural water systems.
Following his education, Yu returned to China and founded Turenscape, a landscape architecture firm that has pioneered ecological urbanism projects globally. His advocacy efforts have been instrumental in shaping China’s national policy on Sponge Cities, and his influence extends far beyond his home country.
In recognition of his contributions, Yu was awarded the Cornelia Hahn Oberlander International Landscape Architecture Prize in 2023. This prestigious accolade highlights his role as a global leader in sustainable urban design.
A Blueprint for the Future
As climate change intensifies extreme weather patterns, urban resilience strategies like the Sponge City concept are becoming increasingly critical. Kongjian Yu’s approach challenges traditional infrastructure mindsets, advocating instead for solutions that work with nature rather than against it.
Cities worldwide are taking note, and as more urban areas integrate these principles, the Sponge City model could become a cornerstone of sustainable urban planning in the 21st century. With rapid urbanisation and climate threats looming, Yu’s vision offers not just a theoretical framework, but a proven, scalable solution to the pressing challenges of urban water management.
