A GIS-Based Approach to Soil Erosion Risk Assessment Using RUSLE: The Case of the Mai Nefhi Watershed, Barka River Basin, Eritrea
2025
Tsegay Bereket Menghis | Pandi Zdruli | Endre Dobos
Soil erosion is a significant environmental issue that threatens the stability of land and agricultural productivity. In Eritrea, erosion remains understudied, limiting effective land management. This study assesses soil erosion and maps erosion risk in the Mai Nefhi watershed using the Revised Universal Soil Loss Equation (RUSLE), integrated with Geographic Information System (GIS) and remote sensing (RS) data. Key parameters were analyzed, including rainfall erosivity (R), soil erodibility (K), slope length and steepness (LS), cover management (C), and conservation practice (P). A severity classification identified five risk levels: low (0&ndash:7), moderate (7&ndash:22), high (22&ndash:45), very high (45&ndash:90), and severe (90&ndash:250) t ha&minus:1 yr&minus:1 with an area coverage of 61.93%, 22.05%, 5.62%, 6.43%, and 3.94%, respectively. Among all the parameters, the LS factor was identified as the dominant driver of soil loss, with erosion rates increasing sharply on slopes above 30%. There was a weak inverse relationship between soil organic matter and erosion (R2 = 0.279), indicating that only 27.9% of the variability in soil erosion rates can be explained by SOM content alone. This result further suggests other dominant factors like slope and land use. The findings underscore the need for slope-sensitive conservation strategies, including terracing, agroforestry, and restrictions on hillside cultivation.
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