GIS-based multicriteria approach for flood risk assessment in Sigus city, east Algeria

Among all natural disasters, floods in urban zones are the most harmful to humans and the economy. To engineers and city managers, making decisions and managing such risk is a tough task. To provide a reliable tool for the urban planner, mainly, to avoid construction in flood-prone areas, this paper presents a useful multicriteria decision analysis (MCDA) methodology for mapping vulnerability to flood risk in urban areas. The approach is applied to Sigus city, east of Algeria, which is considerably damaged by a flood in 1995. The proposed methodology is based on the combination of geographical information systems (GIS) and the analytical hierarchy process (AHP). To fulfill this approach, large data for Sigus city were collected. We considered four criteria that are the most influencing: distance from the main stream “C 1,” site elevation “C 2,” slope “C 3,” and land use “C 4. “Then we made the pairwise comparison between them to get the weight of each criterion. Using ArcGIS software, the criteria weights were transformed into maps and overlaid to produce a final map which is scaled by 05 levels of flood vulnerability. The results show that the criterion “C 1” is the most important. The spatial distribution of flood risk vulnerability is much more important when we approach the main stream. © 2021, Saudi Society for Geosciences.