Spatial occurrence and hazard of flood in the urban city of Ibadan, Southwest, Nigeria

This study assessed spatial flood hazard in the Apete/Ologuneru and Bodija/Agbowo areas of Ibadan, Nigeria, addressing the critical need for localized flood risk information in a region frequently affected by flooding. Using flood occurrence data, a Digital Elevation Model (DEM), and Shuttle Radar Topography Mission (SRTM) data, we applied a robust Multi-Criteria Decision Analysis (MCDA) framework based on the Analytical Hierarchy Process (AHP). Key environmental parameters including elevation, slope, distance to drainage, drainage density, and flow accumulation were integrated to produce flood hazard maps that classified the landscape into less, moderately, and highly vulnerable zones.Results show that Bodija/Agbowo, with a lower elevation range (199–305 m), is more inherently flood-prone than Apete/Ologuneru (222–276 m). Areas with lower slopes across both zones were identified as more vulnerable due to reduced runoff efficiency. Apete/Ologuneru’s higher drainage density and flow accumulation further suggested increased risk from surface water concentration. The spatial analysis revealed that 27.4% of the total study area was classified as highly vulnerable, 41.8% as moderately vulnerable, and 30.8% as less vulnerable. Notably, a significant number of residential structures were located within the moderate to high-risk zones, indicating the potential for substantial socio-economic disruption. To improve resilience and disaster preparedness, the study recommends targeted structural and non-structural interventions, including improved household-level adaptation strategies, community-based flood awareness programs, and the development of GIS-based early warning systems for real-time response and planning in Ibadan.