Flood susceptibility mapping using analytic hierarchy process and ranking method with remote sensing and geographic information system for river basin - Case study in the Ca river basin, Vietnam

Floods are among the most severe natural hazards, causing significant loss of life, property damage, and environmental destruction. Therefore, it is essential to develop a flood susceptibility map as a foundation for proposing solutions to mitigate the impact of floods. The Ca river basin serves as the typical study area. This research utilises data from various remote sensing satellite images, including the shuttle radar topography mission (SRTM) digital elevation model (DEM), Sentinel-1,2, and flood thematic classes such as topography, geomorphology, and hydrometeorological conditions. These were prepared and combined using a geographic information system (GIS) - based analytic hierarchy process (AHP) and ranking method (RM) to delineate flood susceptibility areas within the basin. The two final flash flood hazard maps were validated against the October 2020 flood map using the sentinel application platform (SNAP). The results produced a spatial distribution of flood susceptibility with four levels: low, moderate, high, and very high. In the lower part of the Ca river basin, including districts such as Can Loc, Duc Tho, Loc Ha, Huong Khe, Do Luong, and Nam Dan, the areas highly susceptible to floods range from 16.81 to 18.81%. The research results demonstrated the appropriateness of the methods and the integration of remote sensing and GIS techniques, highlighting significant flood susceptibility areas in the Ca river basin.