Forward-looking flood defense based on high-resolution risk assessment: Lessons from the Nakdong River Basin.

Abstract

Climate change is anticipated to amplify the intensity and frequency of riverine floods, posing significant challenges to existing flood defense systems. This study assesses future flood risks in the Nakdong River Basin, South Korea's largest and most flood-prone basin, by integrating long-term climate, demographic, and economic projections with high spatial resolution. Using GIS-based damage assessment approaches with extensive spatial datasets, we quantify flood risks at the granular level of individual buildings and farmlands across different SSP-RCP scenarios. Results indicate that intensified extreme rainfall events combined with socioeconomic transformations will likely cause a substantial increase in expected annual damage, potentially tripling by 2100 under the SSP5-8.5 scenario. Moreover, the analysis reveals significant heterogeneity in vulnerability, with certain regions and asset categories disproportionately exposed. These findings highlight the critical need for forward-looking, region-specific flood defense strategies that address both spatial and temporal variability.