Global Journal of Earth and Environmental Science

Over the past 30 years, cities in Nigeria have experienced many physical developments, in terms of building, manufacturing industries and others without appreciable infrastructures such as drainages, roads and canals to support them. These developments have made floods a critical challenge for many Nigerian cities. Hence, this research aimed to assess the causes and effects of flood from Eleyele Dam to the nearby settlements in Ido Local Government Areas in Oyo State Nigeria and proffer possible solutions to avert the feature occurrences of flood in the urban area. This research adopted Geographical Information System and Remote Sensing techniques to generate the flood vulnerability map. The study used Shuttle Radar Topographical Mission (SRTM) derived Digital Elevation Model (DEM) (30 m resolution and Quickbird and Sentinel 2 Landsat satellite images (0.25 and 0.75 resolution), topographic maps, soil maps and meteorological data. Seven contributing factors were examined namely; stream power index, distance from the river, Land Use and Land Cover (LULC), drainage, elevation, slope, and flow accumulation. Data was processed using ArcGIS 10.8 and Arcscene 10.8. Multi-criteria analysis through the analytical hierarchical process (AHP) was used to determine the weight of the contributing factors. The results revealed very low (8.3%), low (32.04%), moderate (32.3%), high (21.85%), and very high (5.51%) vulnerable area(s). Generally, the result of flood vulnerable map of the study area revealed the factors responsible for the flooding with proximity to the river (21%), slope (21%), drainage (17%), and Land Use and Land Cover (14%) being the major contributing factors in the study area. Building close to the river bank should be stopped to reduce the vulnerability to flooding. This research therefore recommended regulation of physical development along the river bank to minimize the potential risks and damage associated with flooding in the study area.