Currently the rate of soil erosion is severe in the low lands 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 RUSLE model with GIS environment helps watershed management in assessing and identifying erosion hotspot areas for undertaking required conservation measures. Erer watershed is found in Ethiopian Wabishebele basin. The objective of this study was to Characterize soil erosion and prioritize sub watersheds in Erer watershed in eastern Hararghe. The Revised Universal Soil Loss Equation (RUSLE) integrated with satellite remote sensing and geographical information systems (GIS) as a useful tool for conservation planning was used. Mean annual precipitation, soil map, a 30m digital elevation model, land-cover and management map, land use types and slope length and slope steepness were used to determine the RUSLE values. Homogeneity and consistency test were undertake before each analysis. Homogeneity test for the collected data was homogeneous that the observation was from the same population and the consistency of the rainfall was linear. Mainly the practice of removing plant residues, poor physical soil conservation measures, lack of conservation practice and ploughing the land several times may be the reasons for the high soil loss in the study area. Moreover, the total soil loss in the study area was 7,895,824.22 metric tons per year from 216,762.2ha of land with mean soil loss of 24.61 t/ha/yr. The very high soil loss was observed in steep dissected to mountainous terrain of the upstream of watershed. Out of the 11 SWs, six sub watersheds SW6, SW8, SW9, SW11, SW7 and SW4 were existed under very high erosion rate with mean soil loss ranges from 32.33 to 38.92 t/ha/yr which cover 24 percent of the total land and high soil loss rate was estimated. Soil loss ranges from 21.58 to 27.1 and covers 50 percent of the total land. The watershed has a range of the erosion severity classes of extremely severe, very sever and sever. The steep slope of upstream watershed have contribute high soil loss are more critical and should be given first priority during intervention measures. The poor vegetation cover management and the lack of conservation practice of the area should be improved to reduce the high soil loss throughout of the watershed.
Frezer Yemane (Sat,) studied this question.