Estimating Soil Loss Rates For Soil Conservation Planning in Borena Woreda Of South Wollo Highlands of Ethiopia: The Case from the Legemara Watershed

Abstract

The rate of soil erosion is pervasive in the highlands of Ethiopia. Soil conservation is thus crucial in these areas to tackle the prevailing soil erosion. This area is mainly in the steeper slope banks of tributaries where steep lands are cultivated or overgrazed. The objective of this study is to estimate the rate of soil loss in Legemara watershed in Borena Woreda of South Wollo Administrative Zone in the Amhara Regional State. The study also recommends possible ways of curbing the problem.The study uses the Revised Universal Soil Loss Equation (RUSLE), integrated with satellite remote sensing and the Geographical Information System (GIS) as useful tools for conservation planning. Monthly precipitation, a soil map, a 30m-digital-elevation model, a land-cover map, land-use types and slope-length steepness were used to determine the RUSLE values. Based on the level of soil erosion rates, the study area was divided into five priority categories for conservation interventions. The results show that, 2,344.57 ha (42.97 %) of the total area and 130,102.35 tons ha^-1yr^-1 (77.19 %) of the total soil loss have ranges of the erosion severity classes of very severe and severe, in which case, conservation priorities of first and second order are suggested. Moreover, the total soil loss in the study area was168, 521 metric tons per year from 5456.5 ha, and the average annual soil loss for the entire watershed was estimated at 30.88 metric tons ha^-1yr^-1.

Keywords: Soil Erosion; RUSLE; GIS; Conservation; Watershed; Ethiopia