Assessment of Erosion Vulnerability for Ala River Watershed in Akure South, Akure North, Idanre and Owo Local Government Areas of Ondo State, Nigeria

Understanding and reducing erosion vulnerability in the Ala River watershed is paramount for sustainable land use management and environmental conservation. Hence, the objective of this research is to develop erosion vulnerability map for Ala River watershed in Akure South, Akure North, Idanre and Owo Local Government Areas of Ondo State using the Revised Universal Soil Loss Equation (RUSLE) and Geographic Information System (GIS). Data obtained show that Rainfall and Runoff Factor values range from 827 to 897 mm/year. The watershed has a uniform erodibility factor of 0.05. The slope gradient (%) map of Ala River watershed indicates that most of the watershed is covered with a slope gradient (%) value of (0 - 2.31). The entire watershed has slope length factor (L) value of (0 - 18.3). Results indicate that areas with scarce vegetation, steep slopes, and high rainfall intensity exhibit higher erosion risks, while regions with dense vegetation and flat slopes are less vulnerable. Erosion rates were extremely high in the upper parts of the watershed with the built-up areas in Akure Metropolis, and in the lower tip of the watershed with high areas of bare land and water bodies. The mid areas of the watershed with mostly dense vegetation had low erosion rates. These finding indicate the need for improved land management and conservation practices in high-risk areas to mitigate soil loss and environmental degradation.