Inside China's leading 'sponge city': Wuhan's war with water
By Li Jing in Wuhan
The year before the  floods, Wuhan had been declared one of the country’s first 16 “sponge cities” – areas piloting ecologically friendly alternatives to traditional flood defences and drainage systems. The pace of that project has been accelerated, with a total of 228 projects in the two pilot districts of Qingshan and Sixin to retrofit public spaces, schools and residential areas with sponge features. More than 38.5 sq km of the city has been retrofitted so far, at a cost of 11bn yuan.
Under the sponge city scheme, Wuhan and the other participating areas must ensure that 20% of their urban land includes sponge features by 2020, with a target of being able to retain 70% of storm water. For Wuhan that equates to just over 170 sq km of a total urban area of 860 sq km, and last year the sponge projects were rolled out to a further nine districts.
Retrofitting old residential communities is a particular challenge because there is little space left for construction and existing drainage systems are often outdated and worn out. Such projects can be eye-wateringly expensive. Transforming the 3.8 sq km Nanganqu site involved a total investment of 1.26bn yuan, through a public-private partnership where 20% of the funds came from city government and the rest from the private sector – in this case the iron and steel company that built the affected residential areas for workers in the 1970s and 80s.
Central government subsidies for the sponge cities projects are only set to last until 2020, so scaling up the scheme to cover 80% of the city by 2030 will be a “huge burden” unless the local government finds ways to involve more private investors, says Dr Faith Chan, assistant professor in geographical sciences at the University of Nottingham Ningbo China. “One possible way is to involve real estate developers, because such sponge sites do help increase the value of the land.”