03. Study on flash flood risk zoning in Quang Binh district, Ha Giang province using remotedly sensed images, GIS and FFPI index

Abstract

This study aims to use remote sensing, GIS and the Flash Flood Potential Index (FFPI) to carry out flash flood risk zoning in Quang Binh, a mountainous district in the southwest of Ha Giang province. The approach consists of three important components: (i) identification of factors affecting flash floods and building thematic map of each factor; (ii) mapping flash flood warnings for the influence of each component factor based on the FFPI index; (iii) overlaying flash flood warning layers to create a final flash flood risk warning map, then conducting flash flood risk assessment in order to identify flash flood risk areas. Based on the characteristics of the study area, selected factors include slopes, soil types, land use types, vegetation cover density and rainfall. A total of 5 risk levels were classified, including very low, low, moderate, high and very high. Studied results showed that the area with high and very high risk of flash floods accounted for 12.43% of the Quang Binh’s area, mainly at Tien Nguyen, Tan Nam, Xuan Minh, Tan Bac, Tan Trinh and Ban Ria communes. Identifying areas with high risk levels of flash floods for monitoring and early warning in this study is vital for disaster prevention, environmental resources management, and reducing damages which may cause by flash floods.