With the rapid expansion of urbanization, the area of water-proofing surface keeps increasing while the area of natural ecologies such as primordial rivers and vegetation is decreasing dramatically. Improper urban planning and construction destroyed the primordial hydrological cycle of an area, further weakening abilities of a city to withstand, purify and reserve rainstorm. As a consequence, not only does the waterlogging phenomenon become severe but also lead to the frequent occurrence of problems such as water pollution and water shortage.
Considering serious urban water conditions, Chinese government put forward a mission to establish “sponge cities”, which urges a effective combination of biological environment and treatments of rainwater so that local natural spaces including body of water as well as green space system can be exploited to foster the permeation, regulation and storage and purification of rainwater. Therefore, waterlogging, pollution and shortage issues within a city can be neutralized without damaging primordial biological hydrological characteristics, contributing to an optimized water eco-environment.
From such a standpoint, this research provides planning strategies responding to the call of sponge cities and further conducts empirical investigation and analysis taking Nanchong city as an example. The results indicate that it is fundamental and imperative to organize urban green space system under sponge cities social setting. Research details include:
(1) Summarize the conception of Chinese sponge cities through reviewing the progress and implementation of both domestic and international research and comparing international advanced stormwater management idea, techniques and regulations. Explore fundamental principles, methods and technical classification of establishing sponge cities.
(2) Based on social setting to build up sponge cities and existing integrated planning of Nanchong city, we propose analysis and strategies for Nanchong city of water drain-off, pollution, waterlogging, green space and urban landscape pattern in order to respond to current issues and weaknesses of Nanchong city.