Combined effects of future urban development and rainfall patterns on flood characteristics in the Qinhuai River basin

The spatial patterns of urban development and storm characteristics significantly influence flood forecasting and early warning systems in watersheds. This study simulated the spatial distribution pattern of urban land cover under different future scenarios by coupling multi-objective programming (MOP) with the Path-Generating Land Use Simulation (PLUS) models. Then, the HEC-HMS model was used to analyze the response between urban spatial and storm patterns. Results indicated that natural environmental factors contributed significantly to cropland, forest, and grassland, while socioeconomic factors primarily influenced other land types. 6-h and daily rainfall data analysis consistently recognized common storm types—early, late, and mid-peak (Types I, II, and III). With increasing rainfall intensity , the peak flow of Type I occurs earlier. For all scenarios (Natural, Rapid urban, Ecological conservation, Coordinated development), Type II exhibited the highest peak flows, averaging 31.1 % and 8.5 % higher than Types I and III. Under the rapid urban development scenario, peak flow and volumes for all storm types were the highest. Urban development patterns significantly affected flood processes at the subbasin scale, while variations in rainfall patterns impacted the basin scale more significantly. Future urban planning should balance economic growth with ecological sustainability and guard against Type II rainfall patterns during flood prevention. • LULC spatial distributions under four future urban scenarios are simulated. • Quantifying the impact of human activities on urban flooding. • Comparative analysis of rainfall classification based on different time resolutions. • Flood characteristics for various rainfall types across LULC scenarios are derived.