Assessment of Gully Erosion Using GIS in Anambra State, South East Nigeria

Gully erosion constitutes one of the most severe environmental challenges confronting communities in Anambra State, South East Nigeria. This study assesses the spatial distribution and severity of gully erosion using Geographic Information Systems tools and high-resolution satellite imagery. Secondary topographic data sourced from the Shuttle Radar Topography Mission, combined with field-verified erosion inventory data, are integrated within a GIS environment to delineate erosion-prone zones. Slope, drainage density, soil erodibility, and land use are computed as conditioning factors. The study employs the Revised Universal Soil Loss Equation to estimate annual soil loss across selected communities in Awka South and Orumba North local government areas. Results indicate that steep slopes, sandy loam soils, and degraded vegetation cover contribute significantly to erosion susceptibility in the study area. Communities along the Mamu River Basin exhibit the highest rates of active gully formation. The research recommends targeted afforestation, contour bunding, and institutional enforcement of land use regulations as mitigation measures. Outputs generated in this study, including susceptibility maps, are intended to support the Anambra State Environmental Protection Agency in prioritising remediation programmes. Keywords: gully erosion, GIS, soil loss, Anambra, erosion susceptibility