Integrated flood risk analysis during different SST conditions in a changing climate: A case study of the Korean Han River basin

Abstract:

In this study, an integrated flood risk index (IFRI) was developed using information on hydrological, socio-economic, and ecological components to assess watershed-based flood hazards and vulnerability in the Korean Han River basin, which is a region where flood disasters frequently occur. In total, this study used 15 indicators to create an IFRI map for the region, and 5 categories of flood risk were distinguished: “very high,” “high,” “medium,” “low,” and “very low.” The results, which were presented in ternary diagrams to illustrate the relative importance of the three different components, show that urban areas in the Korean Han River basin have experienced a decrease of 1.0% in terms of the hydrologic component. However, the socio-economic and ecological components have increased by 3.2% and 4.4%, respectively. In rural areas, an increase of 4.8% was found in the hydrologic component alongside decreases in the socio-economic (1.6%) and ecological (2.2%) factors. In addition, the IFRI map shows that 20.02% of the total area of the Han River Basin was classified as having “very high” or “high” flood risk; the size of this high-risk zone has increased significantly by since 1990. This study also evaluated flood risks according to the different phases of conditions, and the results from the analysis indicate that flood risks were worse during strong cold-tongue (CT) and warm-pool (WP) El Niño years. Further analyses of possible factors that affect the vulnerability and resilience of communities to flood hazards in the Han River basin should be conducted on the basis of this research. Accordingly, the results from this study may provide useful data for reducing flood risks in developing areas that are experiencing.