Modelling flood-prone area and vulnerability using integration of multi-criteria analysis and HAND model in the Ogun River Basin, Nigeria

In this study, a GIS-based integration of multi-criteria analysis and the Height Above Nearest Drainage (HAND) terrain model was adopted to delineate potential flood hazard zones and vulnerability of the Ogun River Basin, Nigeria. Flood causative factors were used as input for multi-criteria analysis using an analytical hierarchy process (AHP) and weighted overlay in ArcGIS 10.5 to generate potential flood hazard zones. The flood hazard map was overlaid with demographic population data to identify areas where vulnerable people and assets are located. The results show the varying degree of people's susceptibility to flood hazards. Flood hazard zones were classified into Very High, High, Moderate, Low and Very Low, with area coverage of 1269.40, 14139.50, 7188.40, 17.41 and 0.85 km(2), respectively (occupied by 466 290, 355 542, 69 554, 231 and 54 people, respectively). This study serves as a preliminary guide for early warning and policy decision-making for flood disaster risk reduction.