Estimation of average annual soil loss rates and its prioritization at sub-watershed level using RUSLE: A case of Finca’aa, Oromiya, Western Ethiopia

Abstract

Background: Because of natural and anthropogenic phenomena, most mountain areas experience significant soil loss. It is critical for watershed management to identify high soil loss rates and prone areas. Therefore, the present research aimed to estimate spatial annual soil loss rates and prioritize soil erosion prone areas of the Finca’aa watershed at sub-watershed level. Methods: The revised universal soil loss equation (RUSLE) model, the extension of geographic information system based on five parameters: rainfall erosivity (R), soil erodibility (K), slope length and slope steepness (LS), vegetation cover (C), and conservation techniques (P), was applied. This study also used weather data, a soil type map, a digital elevation model (DEM), and land use land cover, which were all analyzed using ArcGIS 10.4. Results: Annual soil loss rates ranged from negligible to 234 t ha-1 yr-1. The average rates of soil loss was 33.3 t ha-1 yr-1. Approximately 63.36% of the catchment was within and 36.64% of the catchment was above the maximum permissible level, respectively. Approximately 1.96% were in critical condition. Agricultural practices were the primary cause in the watershed’s mountain and hilly areas. Conclusion: The outcome is critical for planners and resource managers interested in long-term watershed management. Also, it is very important for sustainable growth development of 2030 agendas.

Keywords

• geographic information system
• prone area
• soil erosion
• water movement