ESTIMATIMATION OF SOIL LOSS RATES USING RUSLE MODELFOR EL-BAHAY WATERSHED, WABE SHEBELLE RIVER BASIN, ETHIOPIA

Abstract

The rate of soil erosion is sever in the highlands of Ethiopia. Identification of hot-spot areas of erosion and prioritizing areas of intervention is extremely important for reducing further degradation, reclaiming the degraded areas and improving the land productivity of the watershed. The objective of this study was to estimate soil loss rates inEl-bahay watershed of Wabe shabelle River Basin. The Revised Universal Soil Loss Equation (RUSLE) integrated with satellite remote sensing and geographical Information system (GIS) as a useful tool for conservation planning was used. Mean annual precipitation, soil map, a 30 m digital elevation model, land use land cover and management map, land use types and slope length and slope steepness were used to determine the RUSLE values.From 47,989.80 hectors of the watershed area, a 603,082.83 metric tons per year of soil loss ofwas found which ranged from very high soil loss (45.78 t/ha/yr.) to low soil loss 9.81 t/ha/yr. the average annual soil loss of the watershed is12.66 t/ha/yr.The watershed has a range of the erosion severity classes of sever, very highand high soil categories. These sub watersheds, namely SW11, SW1, SW2, SW4, SW20 and SW7 wereconsidered as more critical than the othersand hence, priority intervention were recommended to adopt the management measures in order to reduce the soil loss, to minimize siting up and to safeguardthe -Earthen Dam which is located at the outlet of the watershed.