Comprehensive Performance Assessment for Sponge City Construction: A Case Study

Abstract

Sponge City Construction (SCC) can effectively solve urban areas’ water problems. Green infrastructure (GI), the core of SCC, exhibits a multifaceted capacity to deliver many co-benefits, while grey infrastructure primarily serves the single function of controlling rainfall runoff. However, existing assessment indicator systems fail to either consider or evaluate comprehensive impacts. In this work, a comprehensive indicator system has been established to assess the co-benefits of five different GI measures. The system includes twelve indicators from four aspects, i.e., disaster reduction, economic, environmental, and social benefits. This newly established assessment system is applied to Jinan as a case study. Six out of twelve indicators are evaluated using the self-developed Flood Risk Analysis Software and empirical equations. The results show that the inundation reduction ratios are 11.02%, 9.32%, and 8.02% under the 24-h design rainfall with a 5-year, 10-year, and 20-year return period, respectively. In addition, the corresponding direct flood loss reduction rates are 13.86%, 4.28%, and 4.09%. That is, as the rainfall return periods increase, the disaster reduction benefits become less pronounced. On the contrary, other benefits, e.g., groundwater recharge volumes, are more obvious. The corresponding groundwater recharge volumes are 2.23 million m3, 2.86 million m3, and 2.87 million m3, respectively. The proposed indicator system can be adopted to assess the performances of the different GI combinations, which provides effective support and reference to decision-makers in SCC at the planning and design stages.