Soil erosion risk assessment using geospatial technologies and RUSLE model in Bore Guda Watershed, Southwestern Ethiopia

Abstract

ABSTRACT Soil loss is one of the critical environmental problems caused by poor land use system, especially in developing countries. The loss of top soil through erosion in developing countries leads to loss of fertile soil which in turn increases the problem of food security. This study used the integration of the revised universal soil loss equation (RUSLE) model and geospatial techniques to assess the annual soil loss at Bore Guda watershed of Gibe River basin in southwestern parts of Ethiopia. To calculate the annual soil loss five factors, namely, rainfall erosivity, soil erodibility, topographic, cover management, and conservation practices were considered. The final soil loss severity classes were categorized into low, moderate, high, very high, and severe. The findings of the study revealed that the annual soil loss in the study area ranges from 0 to 775.784 ton/ha/year with average annual soil loss of 54.68 ton/ha/year. The results clearly showed that about 199.05 km2 (9.2%) and 872.63 km2 (41.29%) of the study area were identified as very high and severe soil loss, respectively. The results clearly showed that substantial areas categorized under severe erosion severity classes. Agricultural intensification caused by rapid population growth and high demand for more food is aggravating the problem of soil erosion. The increasing conversion due to agricultural intensification played a significant role in soil loss. The results of the study support decision makers, land administration, environmentalists, and others about the urgency of the situation and how to manage landscapes to minimize the severity of soil loss.