Assessing Impacts of Land Use/Land Cover Change on Different Flood Types Under Multiple SSP Scenarios

Land use/land cover (LULC) exerts a substantial influence on hydrological processes, notably runoff generation, flow routing, and evapotranspiration. To evaluate the impacts of LULC change on different flood types in the Jinhua River Basin, LULC data from four periods (2005, 2015, 2025, and 2035) were incorporated into the Distributed Hydrology–Soil–Vegetation Model (DHSVM). Using a fuzzy decision tree approach, thirty-six flood events were identified and classified as flash floods (FFs), short-rainfall floods (SRFs), and long-rainfall floods (LRFs). Projections of LULC for 2035 under three Shared Socioeconomic Pathways (SSP1-2.6, SSP2-4.5, and SSP5-8.5) were generated by coupling System Dynamics (SD) with the Patch-based Land Use Simulation (PLUS) model. DHSVM was calibrated separately for each flood category, with the 2005 LULC dataset serving as the baseline for parameter estimation. The results revealed a progressive decline in forest land and water from 2005 to 2035, together with an expansion of construction land. By contrast, cultivated land exhibited a fluctuating pattern, expanding initially, then contracting, and recovering thereafter. These land-cover changes increased flood volumes and peak flows across FF, SRF, and LRF alike, largely owing to the growth of construction land and the loss of forest cover and water. Across the three future scenarios, the largest increases were projected under SSP5-8.5, followed by SSP2-4.5 and SSP1-2.6. With respect to flood type, LULC change exerted the most pronounced effects on flood volume and peak flow for LRF, followed by SRF and FF. Under SSP5-8.5, the maximum relative changes in LRF reached 6.74% in flood volume and 8.56% in peak flow. These findings suggest that LRF warrant greater attention in future assessments given their comparatively higher potential risk. Such divergent responses of the three flood types to LULC change can be attributed primarily to intrinsic differences in their flood characteristics.