Urban waterlogging simulation of derived short-duration double-peak rainstorm pattern

ABSTRACT It is actually difficult to quantify the characteristics of short-duration double-peak rainstorm (SDDPR), so the current study on the urban waterlogging simulation of its rainstorm pattern is rare. In this study, a new derivation methodology of SDDPR considering rainfall statistics correlations is proposed. With the non-source inundation method with the geographic information system (GIS)-based storm water management model (SWMM), urban waterlogging is simulated to present the hydrological and hydrodynamic characteristics. The results show that the proposed new derivation methodology of SDDPR reflects the actual rainstorm well, and the simulated urban waterlogging situation of the derived rainstorm confirms the different characteristics of surface ponding at junctions, flow in conduits, and outflows in outlets: with the increase of conditional probability and recurrence period (RP), the situation with average ponding hour-duration and earlier ponding time has increased, which represents more retention water can be produced quickly. With the change of RP from 1 to 10 years, the rate of overloaded conduit numbers with its full-flow time being beyond 0.5 h to total conduit numbers has added from 48 to 78%, waterlogging area of the study area has increased from 105,400 to 2,080,000 m2, ponding depth attains to 50 cm gradually, and the southeast in the study area is prone to be waterlogged.