Rapid Simulation of Urban Rainstorm Flood Based on WCA2D and SWMM Model

For two-dimensional (2D) urban flooding simulation, the traditional 2D hydrodynamic models perform well in characterizing physical mechanism and implementing high-accuracy simulations, but the computational efficiency is relatively inefficient. Trying to combine a kind of cellular automata inundation model (WCA2D, with high computational efficiency) with SWMM model (SWMM/WCA2D) and carry out rapid flooding simulations in Changban catchment (a typical catchment with complex urbanization conditions in Guangzhou), compared to the results of measured inundation data and SWMM/LISFLOOD-FP model, obtained the following conclusions: Validated by the measured inundation data of the "20180607" rainstorm, SWMM/WCA2D model showed good accuracy; According to the evaluation results based on multi-index, the scenario with considering the blockage of main pipe and buildings presented optimal accuracy, and can best characterize the actual conditions of study area; Based on the simulation results of SWMM, the simulation results of WCA2D and LISFLOOD-FP showed little difference and strong correlation, but the computational efficiency of WCA2D was about 3-5 times higher than that of LISFLOOD-FP, indicating that WCA2D has reliable accuracy and higher computational efficiency, providing a new technology for the rapid urban flooding simulation in complex urbanized areas.

Key words: 2D simulation; urban stormwater; WCA2D; model comparison; Guangzhou