INTEGRATED GEOSPATIAL AND MULTI-CRITERION ANALYSIS OF FLOOD PHYSICAL VULNERABILITY IN MOKWA LGA, NIGER STATE, NIGERIA

Abstract

Flooding remains a persistent threat in Mokwa Local Government Area, Niger State, due to a combination of natural topographic conditions and human-induced land changes. The study used geospatial analysis and multi-criteria decision-making to assess flood vulnerability by integrating eleven key physical and environmental factors. Data were obtained from NiMet, SRTM, Landsat-9 imagery, and the HWSD. The Analytical Hierarchy Process (AHP) was used to assign factor weights, and the final vulnerability map was developed using weighted and fuzzy overlay techniques in ArcGIS. The resulting flood vulnerability map classified the area into five categories: Very Low (223 km²), Low (303 km²), Medium (1,473 km²), High (1,624 km²), and Very High (516 km²), out of a total of 4,139 km². This means that over 87% of the land area falls under Medium to Very High vulnerability classes. Land Use/Land Cover (0.198), Elevation (0.168), and Rainfall (0.148) were identified as the most influential factors. The study recommends restricting development in High and Very High zones, enhancing drainage in built-up areas, promoting vegetation and soil conservation in clay-rich zones, and integrating flood risk maps into local planning. The approach illustrates how spatial analysis combined with the Analytic Hierarchy Process (AHP) can support evidence-based flood mitigation and informed land use planning in flood-prone areas.