Effect of sponge city construction on urban waterlogging reduction in semi-humid areas of China

Abstract Urban waterlogging frequently occurs in semi-humid areas due to the short duration of heavy rainfall summer and high rates subsurface hardening caused by high-intensity urban development. To solve problem waterlogging, China has launched construction ‘sponge cities’ made some progress, but there is still a lack comprehensive consideration functional types spatial layout low impact development (LID) facilities. Qian'an, city Hebei Province, one first sponge pilot cities China. This paper focuses on Yanshan South Road its surrounding areas, historical section Qian'an city. Four common LID measures (sunken green space (SG), bioretention ponds (BP), infiltration (IP), reservoirs (RE)) two function are selected combined through centralized (CE) decentralized (DE) different layouts, total 80 design scenarios proposed. Then, using storm water management model (SWMM) calculate effect each scheme peak flow reduction under return periods. The results showed that all can effectively alleviate problem, among which schemes DE-SG-BP (1:1), DE-IP-SG DE-SG-IP (3:1), (1:3), (3:1) had highest rate, up 95.46%. CE-RE-IP CE-IP-RE better hydrological performance occupying less surface space, with rate 8.68% per square meter. Therefore, distributed facilities storage be used built-up limited land use conditions, more obvious reducing waterlogging.