What could we learn from developed countries in combating urban pluvial flooding
In July 2012, a downpour in Beijing made pluvial flooding in cities a heated topic for the whole country. Statistics show that, between 2010 and 2016, 180 Chinese cities were flooded each year on average because of excessive rainfall. In December 2013, the Central Government Working Conference on Urbanisation held in Beijing proposed a solution to the ‘sea views*‘ of cities — the Sponge City programme, which aims to give cities the capability of ‘naturally accumulate, filter and purify rainwater’. However, since the programme is still in a very early stage, and its theoretical conceptualisation, technical roadmaps and metrics system are still to be matured, some projects rely overwhelmingly on, or even indiscriminately imitate, experiences elsewhere, and therefore fail to adapt to local conditions. On the other hand, many Chinese cities have been developed with inadequate drainage system. These aspects, together with the complexity of Chinese cities, have contributed to the under-achievements of the Sponge City programme.
Given the shortcomings, Wang et al (2021) analysed metric systems of similar programmes in developed countries, and compared those with current schemes of Sponge City programmes in China. Major differences were found in metrics for controlling, project design, and implementation. The authors recommended that (1) the metrics system should take into consideration not only rain water infiltration and flood control, but also wellbeing and ecology; (2) programmes need to be designed to adapt to local conditions in view of geological and climatic diversity in China, and active dialogues need to maintained between stakeholders of urban management; and (3) attention needs to be paid to both ex-ante and ex-post analysis of the development, so as to ensure the deliverables from Sponge City programmes.
* Chinese media often mocks the flooded scene in cities as ‘sea views’.
- Wang L., Z. Yun, Q Hu, L. Li, Y. Wang, W. Xiong. Comparison and enlightenment of urban stormwater management index system at home and abroad. Water Resources Protection: 1-9[2021-08-04].http://kns.cnki.net/kcms/detail/32.1356.TV.20210112.1655.008.html. (in Chinese)