Abstract
To better solve the problems of water environment degradation and water shortage caused by urbanization, sponge cities have become a hot research topic. How to evaluate the effect of sponge facilities on runoff and pollution control and conduct benefit analysis is an urgent problem. In this paper, we simulate the runoff control, SS and COD control effects of low impact development (LID) facilities for 0.5a, 1a, 2a, 5a, 10a and 20a rainfall return periods before and after the construction of a sponge city in the southern part of Licang District, Qingdao, China. The results show that the model Nash efficiency coefficient is more than 0.8, which is in line with the reality, and the LID facility can play the role of runoff and pollutants control. 68.2% of the runoff volume is reduced and 70.4% of SS is removed at the return period of P=0.5a, which is the best effect. As the return period increases, the control rates of runoff and pollutants gradually become lower. It can provide a basis for future sponge city effect evaluation.