Student: Emanuel Hempel Study:
The sponge city : An analysis of the positive externalities resulting from such city projects Keywords:
city-scale, water Due to impressive annual economic growth, transforming china in the last 3 decades, the government has been able to put increased focus on transforming cities, or even building new ones that focus on the future and make up for mistakes made in the past. A prime example of such urban development is the city of Wuhan, which due to urbanization has lost 97 of its lakes since the 1980s. The city is built around the merging rivers of Yangtze and Han, which had made it prone to floods, that are especially apparent in during the monsoon season. A pivotal point of this city’s future came, when in 2016, after a week of heavy rainfall metro stations and roads where completely flooded. The economic damages of 263 million dollars also came with a humanitarian disaster costing 14 lives. Belonging to one of Chinas 16 sponge cities, efforts to deal with the reoccurring issue with accelerated after the flooding of 2016. A total of 228 pilot projects in the districts of Qingshan and Sixin alone, saw changes being made to public spaces, schools and residential areas in the shape and form of sponge features. Roughly 38.5 km2 have been subject to landscaping costing 1.5 billion dollars. A prime example of such a project is the Nanganqu
page 27
park, which in 2018, was transformed into a sponge site. New additions include rain gardens, permeable pavements, grass swales, artificial ponds and wetlands. These features absorb excessive amounts of water through the process of soil infiltration, retaining in in under ground storage tanks and tunnels, until it can be discharged into the river. Wen Mei Dubbelaar, director of a water management firm, summarizes this concept beautifully stating that the aim is to ““give space back to the river ... [instead of] fighting the water“. Aside from minimizing damages caused by excessive flooding, sponge cities and sites have a variety of additional benefits. First of all the successfully combat the urban heat island effect, reducing temperatures in Wuhan by 2-3 degrees in such areas as the Nanganqu park. Additionally they create better air quality, mimic natural water cycles, sediment control, reduced water treatment and equipment maintenance costs and water purification. On the other hand these projects require extensive urban remodeling, are very expensive and don’t generate immediate economic benefit making them hard for undeveloped communities to implement.
