6. Application of MCDA-GIS Methods for Soil Erosion Susceptibility Mapping in the Upper Blue Nile River Basin, Ethiopia

Soil erosion is a critical environmental issue in the Upper Blue Nile River Basin, Ethiopia, contributing to significant land degradation, loss of agricultural productivity, and sedimentation in water bodies. Evaluating susceptibility and mapping soil erosion is essential for sustainable soil resource management. Multi-criteria decision analysis (MCDA) and Geographic Information System (GIS) were used to assess soil erosion risk in the Beshlo watershed, Upper Blue Nile River Basin, Ethiopia. The current study analysed drainage density, slope, elevation, precipitation, soil, lineament density, and land use/cover for erosion. The resulting soil erosion zone has three categories: Low-Susceptibility Zones (0.07–0.14). These are largely in the basin’s centre and southwest. Erosion is reduced by gentle slopes, lower rainfall, more stable soils, or more vegetation. 0.15–0.18 Medium Susceptibility Zones Medium susceptibility zones are scattered around the basin but cluster in greenery. These areas may have moderate slopes, intermediate rainfall, and erodable soil types but are more resistant than high-susceptibility zones—high susceptibility (0.19–0.25). For soil erosion susceptibility map accuracy testing, 70 locations were chosen from the research region. In these points, Google Earth images were used to compare the results of this study. The Receiver Operating Characteristic (ROC) curve validated the model with an area under curve (AUC) of 0.832. This high AUC value shows the model’s substantial predictive accuracy in distinguishing erosion risk locations. This study focused on GIS-based MCDA’s relevance and practicability for decision-makers and land managers. This work helps create soil erosion susceptibility maps and identify high-priority conservation sites.