Shanghai‘s Lingang District has installed major green spaces in an effort to improve the city’s drainage and environment. As China has rapidly urbanized, impervious, ubiquitous concrete has blocked the natural flow of water, causing cities to be increasingly vulnerable to flooding. Known as “sponge cities,” the green space development projects in Lingang have incorporated wetlands, gardens, and rooftop plants to more effectively channel excess rainfall. In addition to these green spaces, the streets in Lingang are paved with a permeable pavement, which enables the soil below to absorb water.
Lingang’s experiment in green flood prevention may serve as a model for other urban areas dealing with the impact of extreme weather and rapid development. “In the natural environment, most precipitation infiltrates the ground or is received by surface water, but this is disrupted when there are large-scale hard pavements,” said Wen Mei Dubbelaar, director of water management China at Arcadis, according to the Guardian. “Now, only about 20-30 percent of rainwater infiltrates the ground in urban areas, so it breaks the natural water circulation and causes waterlogging and surface water pollution.”
Lingang, also known as Nanhui New City, is fortunate in that it still maintains significant open space of land and water with which to implement these innovative ideas. Older areas of Shanghai have proven more challenging to retrofit. Green roofs seem to be the most effective solution for Shanghai’s more fully developed districts, though even older spaces like the former industrial West Bund Riverside have been transformed to capture excess water. By 2030, 80 percent of the surface area of each sponge city district will be required to incorporate some form of green flooding prevention. Due to challenges, including currently inadequate funding from the central government, it seems unlikely that these sponge cities will be able to meet that goal.
Nevertheless, Lingang’s solution to a global problem comprises an inspiring step towards a better urban environment. “Sponge city infrastructure is beneficial because it is also changing the living environment, helping with pollution and creating a better quality of life in these areas,” said Dubbelaar. “The initial driver for sponge cities was the extreme flooding of urban areas, but the change in mindset, that development should have a more holistic, sustainable approach, is an extra benefit that is evolving during this project.”
Via the Guardian