Regional-scale assessment of climate change impacts on land use–specific hydrological processes in the Geum River Basin, South Korea

Study region Geum River Basin, South Korea, East Asia Study focus Climate change is expected to substantially modify hydrological processes: however, the mechanisms underlying these changes remain highly dependent on regional characteristics and land use patterns. In this study, we provide a regional-scale assessment of the effects of climate change on land use specifics hydrological processes in the Geum River Basin, South Korea, which is a key water-supply region characterized by rapid urbanization and a mixture of agricultural– and forested landscapes. New hydrological insights for the region Climate change is intensifying hydrological variability across the Geum River Basin, with fast-response components such as surface runoff generally increasing. However, slow-response components, particularly groundwater recharge and baseflow, are projected to decline. Runoff sensitivities to precipitation and temperature exhibit three distinct response patterns corresponding to urban land, agricultural land, and forestland–grassland, demonstrating that climate drivers propagate through hydrological processes in land use–specific ways. Although projected increases in precipitation enhance meteorological resilience, they do not necessarily translate into improved hydrological water availability, especially in highly urbanized sub-basins. These findings highlight the importance of regionally tailored adaptation strategies. For the Geum River Basin, expanding storage capacity, conserving permeable and vegetated surfaces, and improving seasonal water allocation are identified as priority measures for sustaining water and ecosystem resilience under future climate conditions.