New Water Policy and Practice Issue 4, Number 1, Fall 2017 | Page 61

Reviews of Sponge City in China
In China, some researchers have developed the case study of perfor-
mance of LID or GI in water quantity and quality. Research studies related to
sponge city progress in big cities such as Beijing, Shenzhen, and Chongqing,
which include field experiments of GI for identifying their hydrological per-
formance, retrofitting scenarios simulation through models on small scales,
and comparison of different infrastructures.
Field experiments in Chongqing showed that the annual retention
volume by green roof could be 758.7 mm with a retention rate of 68% (Zhang
et al. 2015). Liu et al. (2014, 2015) conducted research to evaluate the effec-
tiveness of GI on reducing the volume and peak flow at community scale and
compared the reduction effectiveness under various setting sizes of GI. Qin
et al. (2013, 2016) developed several research studies to examine the effect
of LID on a site scale, the mitigation of urban flooding provided by swale,
permeable pavement, and green roof in different rainfall characteristics and
to model green roof ’s hydrological performance with different irrigation
schemes for maintenance. Although there is progress in sponge city related
research, few of them succeed to establish an integrated model, except the
optimization analysis for BMP design aiming at achieving either maximum
runoff control or total minimum system cost in the newly constructed Bei-
jing Olympic Village conducted by Jia et al. (2012).
Figure 2: Stormwater and flooding in underpasses
Upgrading of the rainwater facilities around underpasses is one of
the most concerned issues of stormwater management in Beijing (Figure
2), where the flooding causes a lot of pressure to governments from public
opinion, and to some extent arouses their concern of the sponge city con-
struction. Yin et al. (2015) simulated the flooding and the effect of enlarged
pipeline on flooding in underpasses of a severe rainstorm that took place
on July 21, 2012. Other researchers developed new inundation simulation
algorithm and validated by campus flooding event (Zhang et al. 2016). How-
59