Geological suitability of natural sponge body for the construction of sponge city—a case study of Shuanghe Lake district in Zhengzhou airport zone

Natural and geological environmental conditions have an important impact on the planning and construction of sponge cities. This paper analyzes geological factors that influence the usage of natural sponge bodies, taking the Shuanghe lake district of Zhengzhou airport zone as an example. An evaluation system with seven factors has been established and the weights of these factors are determined using the analytic hierarchy process (AHP) method. Overlay analysis is then carried out on all factors using GIS to evaluate the geological suitability of the construction of the sponge city. The results show that geologically suitable area for city construction in Shuanghe lake district accounts for 12.3%, relatively suitable area accounts for 76.1%, and relatively unsuitable area accounts for 11.6%. For suitable and relatively suitable areas, we should make full use of the advantages of surface infiltration, vadose zone transportation and aquifer storage to build a sponge city infrastructure with geological engineering as the main component, supplemented by engineering measures such as surface water storage and drainage, and jointly establish a sustainable urban hydrological cycle. For less suitable areas, artificial rain and flood control works, such as roof garden, should be considered. The findings of this paper can serve as an important reference for sponge city planning and construction not only in the research area but also in other regions with similar geological conditions.