Soil Loss Estimation for Soil Conservation Planning using Geographic Information System in Guang Watershed, Blue Nile Basin

Abstract

This research was carried out to spatially predict the soil loss rate of Guang watershed with a Geographic Information System (GIS) and Remote Sensing (RS). Revised Universal Soil Loss Equation (RUSLE) adapted to Ethiopian conditions was used to estimate potential soil losses by utilizing information on  rainfall erosivity (R) using interpolation of rainfall data, soil erodibility (K) using soil map, vegetation cover (C) using satellite images, topography (LS) using Digital Elevation Model (DEM) and conservation practices (P ) using satellite images. Based on the analysis, the mean and total annual soil loss potential of the study watershed was 24.95 tons ha^-1 year^-1 and 8,732.5 tons ha^-1 year^-1, respectively. About 147.9 ha (64%) of the watershed was categorized none to slight class which under soil loss tolerance (SLT) values ranging from 5 to 11 tons ha^-1 year^-1 whereas moderate to high soil loss potential covered about 202.1 ha (36%) about several times the maximum tolerable soil loss (11 tons ha^-1 year^-1). The study demonstrates that the RUSLE using GIS and RS provides great advantage to spatially analyze multi-layer of data. The predicted amount of soil loss and its spatial distribution could facilitate sustainable land use and management.

Keywords: soil erosion; RUSLE; GIS; Guang watershed; Ethiopia