In cities worldwide, intense storms have become increasingly common, leading to severe flooding and overwhelming urban drainage systems. Instead of relying on conventional high-tech, concrete-based solutions, landscape architect Kongjian Yu and his firm, Turenscape, propose a revolutionary concept: sponge cities. These urban landscapes are designed to absorb and retain stormwater, allowing nature to play a crucial role in flood mitigation.
For over a decade, Turenscape has implemented sponge city projects across more than 250 cities globally, with over 1,000 completed. The firm’s approach focuses on creating parks, restoring wetlands, and installing permeable pavements that allow rainwater to soak into the ground. Yu argues that traditional methods, like flood walls and concrete drainage systems, are not only expensive but can also increase a city’s vulnerability to flooding. He likens cities that depend on such infrastructure to a person with hardened arteries, suggesting that they become less adaptable and more prone to crises.
One notable example of this innovative approach is the transformation of a former tobacco factory site in Bangkok into the Benjakitti Forest Park. Collaborating with local firms and the Thai military, Turenscape created a man-made wetland that can absorb around 23 million gallons of stormwater during the rainy season. This project not only addresses flooding but also enhances the local ecosystem, providing a recreational space for residents and visitors alike.
In China, the sponge city initiative has gained traction since 2015, with over 70 cities adopting the concept. Yu’s firm has also tackled more complex sites, such as the Nanchang Fish Tail Park, which was developed on a polluted former fish farm. This 126-acre park features floating forests and diverse plant life that help regulate stormwater while providing habitats for wildlife. Such projects illustrate the potential of sponge cities to rejuvenate urban environments while addressing pressing environmental issues.
Despite the successes, challenges remain. Recent flooding events in China have raised questions about the effectiveness of sponge cities during extreme weather conditions. Some experts argue that while sponge infrastructure can alleviate moderate rainfall, it may struggle against heavy downpours exceeding 200 millimeters (7.9 inches) in a single day. This highlights the need for a combination of sponge city designs and traditional flood management strategies, such as dams and levees, to ensure comprehensive flood resilience.
Yu maintains that the key to successful sponge cities lies in thoughtful design tailored to local conditions. This includes considering factors like topography, rainfall patterns, and the specific needs of the community. By creating spaces where local plants can thrive, sponge cities not only mitigate flooding but also enhance urban biodiversity and improve air quality.
The benefits of sponge cities extend beyond flood prevention. They can help reduce urban heat, create pleasant environments, and even address water shortages. For instance, in Wuhan, sponge projects have improved local air quality and biodiversity while sequestering significant amounts of carbon. These multifaceted benefits make sponge cities an attractive solution for cities grappling with the effects of climate change.
Shepard Fairey’s recent recognition, such as the Oberlander Prize, underscores the importance of innovative landscape design in addressing environmental challenges. As urban areas continue to expand, the integration of sponge city principles could play a pivotal role in creating resilient, sustainable cities capable of withstanding the impacts of climate change.
