Effect of infiltration rate changes in urban soils on stormwater runoff process

Rainstorms and floods in cities has increased largely in recent years because of both extreme climate events and city imperviousness increasing. It's generally acknowledged that water infiltration change of soils in urban green space area has an impact on urban waterlogging problems, but the degree of the impact as well as how it affects is still not fully clear. In response, this paper theoretically explored the mechanism and extent of the effect of infiltration change on urban stormwater runoff. On the base of the storm water management model (SWMM) and the Horton model, the effect of changes in initial infiltration rates and stable infiltration rates of urban soils are discussed at different levels under three cases. The results show that the change impact is closely related to rainfall intensity and urban imperviousness. Compared to changing the initial infiltration rates of soil, changing the stable infiltration rates or the overall infiltration can mitigate urban flooding more effectively. Under low rainfall intensity and urban impermeability, there exists a critical value of the stable infiltration rate. The critical value is not a constant, but increases with rainfall intensity and urban impermeability increasing. The rainfall intensity and urban impermeability play an important role in the soil infiltration change affecting urban runoff process. Overall, this paper presents new insight to understand the effect of water infiltration change on urban flooding and waterlogging problems.