Identification of soil erosion hotspot areas for sustainable land management in the Gerado catchment, North-eastern Ethiopia

Abstract

In Highland Ethiopia, soil erosion is one of the main forms of land degradation which has a wide range of undesirable on-site and off-site impacts. It is therefore essential to mitigate soil erosion through site-specific and problem-oriented management practices. The research employed Revised Universal Soil Loss Equation (RUSLE2) model to identify hotspot areas of soil erosion and prioritize land management intervention in the Gerado catchment, North-eastern Ethiopia. The parameters required for the model were acquired from different sources and integrated with ArcGIS tools to estimate soil loss rates of the study catchment. Mean annual soil loss rates were estimated to be between 5 and 100 t ha–1 yr–1 on flatter and steeper slopes respectively. Over 75% of the catchment area had an average soil loss above the estimated tolerance soil loss rate of 18 t ha–1 yr–1 for the country. In order to identify hotspot areas, the catchment was classified into severe, very high, high, medium, low and very low erosion risk categories. Based on the study result, it is recommended that areas with severe, very high and high erosion risk having estimated soil loss of 25 t ha–1 yr–1 or over are prioritized for land management intervention. Areas which require the immediate implementation of soil management approximately accounted for 75% (5025 ha) of the total catchment. The results showed that the severity of erosion was linked to the slope steepness, steep slope cultivation, absence/lack of effective conservation measures and sparse nature of the steep slope vegetation cover.