Do Storm Characteristics Affect Urban Flood and Its Control? Assessment of Urban Drainage System Considering Rainfall Spatial Variability

The interaction between rainfall spatial–temporal variability and watershed response has been extensively studied in recent decades. Due to the influence of spatiotemporal non‐uniformity and variability in urban rainfall processes, the urban drainage system can exhibit different capabilities of handling flood risk. In this study, we evaluate the urban drainage system performance responsive to rainfall spatial variability by constructing nonuniformly structured rainfall events with varying intensities, employing several systematic performance indices, and accounting for the cumulative transmission effects of different stormwater management strategies. Our results show that when storm centers are located in the central part of the basin, the spatial variation extent of rainfall—quantified by the standard deviation ( σ ) of a Gaussian distribution—has minimal influence on flood severity. Comparative analysis of flood spatial patterns under varying storm centers allows for the identification of critical rainfall zones, and heavy rainfall concentrated in these zones significantly amplifies system‐wide flood risk. While rainfall intensity affects system performance, uncertainty in storm positioning leads to substantial variability in hydrological response, leading to a wider range of flooding node ratios, especially under return periods of 20‐year or 30‐year. The performance of stormwater management infrastructure is also modulated by hydrological forcing variables, notably rainfall intensity and storm center location. The findings provide us with insight into the impact that rainfall structure can pose on the urban drainage system performance and stormwater management efficiency.