GEOSPATIAL MAPPING OF GULLY EROSION SUSCEPTIBILITY

ABSTRACT

Gully erosion is one of the major challenges faced in the southern part of Nigeria. Thisproject aims to mapping of gully erosion invested areas within Etsako West Local Government Area of Edo State, Nigeria and further produce the susceptibility map. The methodology entails the acquisition of Geo-environmental datasets involvingcloudfree high-resolution satellite images, SRTM DEM data, FAO soil which aid ingullyerosion analysis such as slope aspect, slope degree, slope-length (LS), topographical wetness index (TWI), plan curvature, profile curvature, soil texture, streampower index(SPI), Altitude were selected to produce maps of gully erosion susceptibility. Multi-criteria decision-making and statistical method, such as frequency ratio (FR) wereutilized during data analysis to investigate the spatial auto correlation betweengullyerosion and each factor. The results obtained showed that soil texture and the slope of the area were themost important gully susceptibility factors, then the gully susceptibility map was createdinGeographic Information Systems using the same scale of 1: 160,000. The computationofthe Area Under Curve (AUC) resulted in an acceptable level of 76.47%furtherconfirmed the model's validity. Overall, the project contributed to a better understandingof gully erosion susceptibility and provided valuable tools for land management andconservation strategies.