Delineation of Erosion-Prone Areas in Cross River State Using GIS and Multi-Criteria Analysis

Soil erosion is a persistent land degradation problem across southern Nigeria, with severe consequences for agricultural productivity, infrastructure integrity, and community displacement. This study delineates erosion-prone areas in three Local Government Areas of Cross River State, namely Abi, Yakurr, and Ikom, using Geographic Information Systems and multi-criteria analysis. Spatial data layers including slope gradient derived from SRTM DEMs, soil erodibility from the FAO Harmonised World Soil Database, rainfall erosivity from the Nigerian Meteorological Agency archive, vegetation cover from NDVI computations, and land use from Sentinel-2 classification are integrated within the GIS framework. The Revised Universal Soil Loss Equation is parameterised and applied spatially to estimate annual soil loss rates per pixel. Resultant erosion risk is classified into five categories from negligible to extreme, and validation is performed against field-observed gully locations and published Cross River State environmental degradation reports. Findings indicate that the steeper terrain of Abi LGA coincides with the highest erosion risk, exacerbated by deforestation associated with smallholder farming expansion. An estimated 15,000 hectares of the study area fall within the extreme risk class, warranting immediate intervention. The study provides actionable spatial intelligence for the Cross River State Forestry Commission and the Ecological Fund Office of the Federal Government. Keywords: soil erosion, GIS, multi-criteria analysis, Cross River State, RUSLE.