by+Li+Zhuoxi

“Sponge city” is a storm water management concept in city planning that attaches great significance to the design and construction of underground pipe networks. The architecture， roads， watercourses and green spaces designed according to this concept can hold， absorb， and drain water using ecological methods， so that rainwater can be collected and recycled for multiple uses.

In the government work report that he delivered to Chinas top legislative body on March 5 during its annual session， Premier Li Keqiang called for coordinating urban development above and below the ground by building at least another 2，000 kilometers of underground utility tunnels to promote the construction of sponge cities and solve urban flooding.

At present， most Chinese cities use a model in which water is discharged quickly as rainwater falls to the ground. Yet large areas of hardened concrete prevent water from seeping into the ground， blocking the natural water circulation system. To solve problems plaguing the development of traditional cities， sponge cities will adopt engineering measures to control city rainwater runoff and minimize environmental destruction caused by city development and construction.

China has already formulated a clear timetable for the construction of sponge cities， which are considered important symbols of urban development and the transformation of construction modes. The country has listed more than 130 cities in the sponge city construction program. The Guiding Opinions of the General Office of the State Council on Advancing the Construction of Sponge Cities stated that the construction of sponge cities will minimize the impact of city development and construction on the ecological environment. China also set an ambitious goal of making 20 percent of its urban areas meet the standards of “sponge cities” by 2020 and 80 percent by 2030.