Watershed-based soil erosion and sediment yield modeling in the Rib watershed of the Upper Blue Nile Basin, Ethiopia

Abstract

Soil erosion is a major environmental problem that degrades topsoil and agricultural land productivity in mountainous areas such as Ethiopia. Soil erosion estimation is critical for the planning of erosion control plans in an agriculture-dependent economy. The current study used the Revised Universal Soil Loss Equation (RUSLE) model to evaluate the spatial distribution of annual soil loss and sediment yield in the Rib watershed. The main factors affecting soil erosion and sediment yield include vegetation cover, topography, soil, and climate. Soil erosion and sediment yield maps should be produced with these elements in account to describe locations with high soil erosion and sediment yield risks and to ensure improved erosion mitigation strategies in watersheds. The five input parameters were rainfall erosivity (R), soil erodibility (K), slope length-steepness (LS), cover-management factor (C), and support practice (P). The RUSLE model, when combined with remote sensing technology, has the ability to provide accurate and low-cost erosion and sediment yield risk maps in the Rib watershed. The estimated average annual soil loss was 25.53 t ha−1 yr−1. The soil loss rate was higher in the steeper and topographically dissected part of the watershed. Sediment delivery ratio ranges between 0 and 0.82. The outcome undoubtedly aids in the identification of priority locations for the adoption of sustainable land management and soil erosion mitigation conservation strategies.