Comprehensive Flood Risk Assessment for Quang Tri Province

Quang Tri, located in the central region of Vietnam, regularly experiences prolonged and extreme rainfall that causes severe and widespread flooding. This has resulted in significant losses in terms of both lives and property. Therefore, an integrated flood risk map is an essential tool for supporting disaster response and prevention efforts, utilizing a multi-criteria analysis approach to assess flood risks. This study proposes a method for constructing flood risk maps for the downstream areas of river basins in Quang Tri Province, based on the combination of the unweighted method by Iyengar and Sudarshan with multi-criteria and spatial analysis. The results indicate that during the historic flood in October 2020, the level of flood risk varied significantly among communes in 10 districts in the downstream areas. Specifically, the Hai Phong, Dien Sanh, Hai Hung, and Hai Quy communes in Hai Lang district had the largest proportion of the highest risk area (level 5), accounting for 3.76% of the total area. The area classified as medium risk (level 3) represented approximately 16.54%. The resulting flood risk map enables Quang Tri authorities to focus disaster prevention and response efforts more effectively on the most vulnerable areas identified, particularly the high-risk communes in Hai Lang district.