ASSESSMENT OF SOIL EROSION RISK USING RUSLE MODEL AT HARO BAKE WATERSHED OF YABELLO DISTRICT, BORANA ZONE, SOUTHERN ETHIOPIA

Soil erosion has become one of the global environmental hazards that limits the survival of people today and hinders sustainable socio-economic development worldwide. It is most severe in the tropical and subtropical regions of the world, especially in developing countries like Ethiopia. Estimating the extent of soil loss and understanding the spatial distribution of erosion-prone areas are critical for planning and effectively implementing soil conservation measures with limited resources. Accordingly, this study was conducted in Haro Bake watershed, where soil erosion and various other land degrading processes aggravate the sedimentation process. Thus, it is claimed that effective conservation planning and sustainable land management practices at watershed level are critical. Therefore, this study was mainly proposed to determine the soil loss rate, its spatial pattern and identify hotspot areas using Revised Universal Soil Loss Equation (RUSLE) model in Haro Bake watershed. The Revised Universal Soil Loss Equation (RUSLE) model integrated with Geographical information system (GIS) and remote sensing was used. Soil losses were estimated based on principles defined in the RUSLE that relate the soil erosion process to rainfall erosivity, soil erodibility, topographic factors, land cover and conservation practices. Primary and secondary input datasets were collected from different sources to analyze the RUSLE parameters in ArcGIS 10.8 environment. For the overall analysis, input factors were multiplied together in a raster calculator to quantify soil loss throughout the watershed. The result of annual soil loss in Haro Bake watershed ranged from 0 to 146.91 t ha-1 yr-1 with a mean annual value of 3.9 t ha-1 yr-1. Based on the extent of soil erosion, the study area was classified into five priority classes for conservation measures. The result showed that 98.03% of the studied watershed had very slight soil loss rates, which accounted for the largest proportion of total soil loss. The RUSLE model was highly sensitive to the C factor followed by P factor. Based on mean annual soil loss SW-1, SW-3, SW-12, SW-7, SW-9, SW-8, SW-2, SW-11, SW-4, SW-10, SW-6 and SW-5 got 1 to 12 priority levels. Two sub-watersheds (SW-1 and SW-3) with a combined area of 26.69% of the total land and a mean annual soil loss rate that surpassed the maximum tolerable soil rate had been identified as hotspot areas of the watershed. Therefore, these Two sub-watersheds require prior intervention to prevent soil erosion and maintain agricultural production