China plans an ambitious alternative to grey urban expanses. This City Lab article explains:
"... News reports of fatal floods come as regularly to city dwellers as the annual monsoon season... water has become the nemesis of China’s 680 million urbanites, whose concrete landscape was not built adequately to withstand the forces of nature... Since 2008, the number of Chinese cities affected by floods has more than doubled. Severe and extreme droughts, too, have become more serious since the late 1990s. Chronic water shortages in northern China have led to the construction of a $81 billion canal to transfer water south to north...
In September, the government rubber-stamped the development of 16 model “sponge cities”—an ecologically friendly alternative to the gray urban expanses of modern China. These will require infrastructure retrofits of existing cities all over China, ranging from Xixian New Area in the north, with about 500,000 people, to Chongqing in the south, with a population of 10 million... Each city will receive 400 million RMB ($63 million) per year for three years to implement projects...
China began experimenting with sponge-related urban design ideas more than a decade ago. In 2000, one of the first large studies involving low-impact development (LID)—a method of natural stormwater management—was used in the design of a housing block called Tianxu Garden in Beijing. During the flood of 2012, the apartments easily survived the disaster...
As Bill Gates (now famously) tweeted, between 2011 and 2013, China used more cement than the United States did over the entire 20th century. And concrete is not permeable...
Sponge-city design could also run up against China’s centralized planning system...“Some aspects of sponge city will not work in northwest China, but will work in southeast China, depending on the localized climate,” says Buck. (For instance, Wuhan deals with regular flooding, while in Xixian, the problem is drought.) “But China’s not used to doing that. Beijing chooses one model and stamps it out to every part of the country.”
Finally, there is the delicate question of financing. While the government has promised to fund 16 sponge cities in the short term, it is looking for public-private partnerships to make a long-term social investment. Still, it’s not clear how sponge cities will make money for investors..."