Mapping Soil Erosion Hotspot Areas in the Bwabwata Watershed North Central Highlands of Ethiopia

Soil erosion produces major environmental problems in Ethiopian highlands while continuing to affect the Bwabwata watershed as an ecological issue. Effective control of soil erosion in watersheds necessitates the identification of erosion hotspots. The identification of such hotspots has been missing from past research investigations within this area. A GIS-based RUSLE model implementation helps estimate soil loss and determine the order of priority for sub-watersheds in terms of soil and water conservation planning. Mean annual precipitation, together with digital soil data and digital elevation models combined with slope steepness measurements, allowed the computation of RUSLE output values. The RUSLE model incorporated into a GIS platform evaluated soil erosion effects resulting from land use and land cover changes in three specific periods. The quantitative evaluation shows both cropland and settlement areas extended from 2004 to 2024, but forest and shrubland decreased because of their conversion to different land uses. The watershed experienced a significant elevation of mean annual soil erosion rate from 28.63 t/ha/yr in 2004 to 32.99 t/ha/yr in 2014, with a subsequent minor erosion reduction to 30.93 t/ha/yr in 2024. Currently, the total soil loss in the study area amounts to 117,545.25 tons from 3,800 hectares. The soil loss tolerance threshold exceeds in 42% of the study area, which spreads across 1,595.76 hectares, resulting in high erosion risk areas. A successful approach to safeguarding watershed resources requires specific allocation of SWC efforts toward high-risk sub-watersheds, along with planned LULC management.