7. Identifying Soil Erosion Hotspot Areas Using GIS and MCDA Techniques: Case Study of the Dengora and Meno Watersheds in Belesa Woredas, Amhara Region

In Ethiopia, accelerated soil erosion and land degradation have become key issues because of the country’s rugged terrain and steep slope topography. The main objective of this study was to identify soil erosion hotspot areas in the Dengora and Meno watersheds using the Revised Universal Soil Loss Equation (RUSLE) and multicriteria decision analysis (MCDA) techniques. To achieve this objective, the RUSLE model was used to estimate potential soil losses by utilizing information on soil, land use/cover, topography, and climate data. The MCDA technique considered land use, soil type, topographic wetness index, stream power index, and potential location of gullies. The factors were weighted using a pairwise comparison matrix, and weights were combined using weighted overlay. Based on the RUSLE model, the average annual soil loss of the Dengora and Meno watersheds reached 223.97 and 256.09 tons ha⁻¹ yr⁻¹, respectively. In the Dengora watershed, 70.4%, 18.7%, 10.74%, and 0.14% of the total watershed area were slightly, moderately, highly, and very highly sensitive to soil erosion, respectively, while in the Meno watershed, 76%, 16.54%, 7.3%, and 0.14% were the corresponding values. The GIS-based MCDA technique revealed that in the Dengora watershed, 9.7%, 64.5%, 18%, and 7.8% of the total watershed area were highly, moderately, slightly, and currently not sensitive to soil erosion, respectively. The corresponding values for the Meno watershed were 6.1%, 71.3%, 23.23%, and 0.375%, respectively. Based on validation and field-level observations, the MCDA model prediction was more accurate than that of the RUSLE model. Both watersheds were at moderate risk. The bottomlands of the watersheds were highly sensitive to erosion. Therefore, immediate attention should be given to soil and water conservation practices.