Flood risk assessment using analytical hierarchy process: a case study from the Cheliff-Ghrib watershed, Algeria

Flooding is one of the most devastating natural disasters brought on by climate change in North Africa. The occurrence of flood risk is due to a combination of natural and man-made variables, necessitating a better knowledge of its spatial scope. The goal of this study is to locate and map flood-prone regions in the Cheliff-Ghrib watershed. Within the ArcGIS interface, this study is based on the integration of multi-criteria data such as slope, drainage density, type of soil, rainfall, population density, land use and sewer system density. For flood risk assessment and mapping, the Analytic Hierarchy Process (AHP) technique was employed as a multi-criteria analysis, allowing the integration of numerous factors under two criteria namely, hazards and vulnerability. The AHP flood risk map reveals that areas at high and extremely high risk of flooding cover 22.5% of the study area. According to the findings, the Cheliff-Ghrib watershed is extremely vulnerable to flooding. Eight of the Chelliff-Ghrib watershed's 15 municipalities (8/15) are at high risk of flooding, necessitating the development of efficient flood mitigation solutions for future flood events.