Journal of Geography  & Natural Disasters
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Watershed Prioritization to Flood Susceptibility Using Geospatial Techniques in a Southwestern Nigeria Basin

Adesola Elizabeth Akindejoye1*, O Alabi2 , T B Adedoja2

Drainage morphometric is an essential aspect required for effective control of flooding. Ureje Ogbese River Basin (UORB) has experienced flooding repeatedly for years which has led to the destruction of lives and valuable properties. Thus, it is pivotal to examine the morphometry of UORB and access sub-watersheds susceptibility to flooding. In this work, the 30 m-Digital Elevation Model (DEM) from the Shuttle Radar Topographic Mission SRTM was employed to calculate the morphometrics of the drainage basin. To determine the susceptibility to flooding within the study area, the total ranking technique was adopted to prioritize the sub-watersheds. The results from the morphometric analysis reveal that the UORB watershed is characterized by a dendritic drainage pattern with a total of 5985 streams segment and a drainage area coverage of 2642 km². The drainage basin has a sixth-order stream that is controlled by the lithology and structure. Prioritization results reveal that 37.5% (sub-watershed III and V) of the study area is at a very high priority to flooding susceptibility while 47.7% of the basin (sub-watersheds II, VI, and VII) is at high priority to flood susceptibility. Hence it is recommended that anthropogenic activities along identified sensitive slopes should be controlled and sensitization in high-risk communities is necessary so that adequate preparations will be made to mitigate future occurrences of floods.