Modeling of Soil Loss and Identification of Erosion Hot Spot Areas Using RUSLE Integrated with GIS for Appropriate Conservation Practices in Muga Watershed, Highlands of Ethiopia

Girum Getachew Demeke

doi:10.7176/jees/9-10-03

Abstract

Over cultivation, deforestation and free grazing are major factors facilitating soil erosion. Nowadays; in lower parts of Muga watershed soil erosion become as a continuous environmental problem. In this study an attempt has been made to modeling soil loss and identify the most erosion sensitive areas by using Revised Universal Soil Loss Equation integrated with GIS and remote sensing techniques for planning appropriate conservation measures in Muga watershed. The annual soil loss amount was estimated by using the Revised Universal Soil Loss Equation (RUSLE). Digital Elevation Model, digital soil map, thirty years rainfall records of six stations, and land cover data (Landsat images) were used to develop RUSLE soil loss variables. The annual soil loss rate from the catchment were estimated by integrating RUSLE parameters using raster calculator tool. The annual soil loss rate varies between 0.02 ton/ha/yr and 41.789 ton/ha/yr. The total annual soil loss in the watershed was 59751.41 tones, of these, 12806.15 tons were lost from 371.19 km 2 , 26562.44 tons from 214.30 km 2 , 15300.94 tons from 50.52 km 2 , 4059.05 tons from 4.61 km 2 , and 1022.83 tons from 0.37 km 2 of land per year. The rate of soil eroion was high in the lower part of the watershed. Slope gradient and length factor was the main factor for soil erosion increment followed by Support Practice (P) factor. As result of soil erosion cross tabulation; steep slopes, Rendzic leptosols and dominantly cultivated areas were detected as very severe erosivity. Therefore, the lower parts of the study needs to undertake effective soil and water conservation practices. Keywords: Soil loss, RUSLE, GIS, Remote sensing, Moga Watershed, Erosion hot spot areas DOI : 10.7176/JEES/9-10-03 Publication date :October 31 st 2019

Highlights

Soil erosion by runoff is the process of detaching and transporting of soil particles by flowing water to downstream areas (Kunta, 2009)
Soil erosion has an adverse effect for developing countries like Ethiopa, since agriculture is the main source of income and food, which is dependent on the soil fertility (Hurni, 1993)
Revised Universal Soil Loss Equation (RUSLE) equation was integrated with Arc GIS 10.1 technique to conduct cell by cell calculation of mean annual soil loss rate and to identify high erosion hot spot areas in Muga Watershed

Summary

Introduction

Soil erosion by runoff is the process of detaching and transporting of soil particles by flowing water to downstream areas (Kunta, 2009). Soil erosion has an adverse effect for developing countries like Ethiopa, since agriculture is the main source of income and food, which is dependent on the soil fertility (Hurni, 1993). Soil erosion has been considered as the most serious land problem, due to it’s on-site and off-site effects on the food security and the economy of the country (Hurni, 1993; Sutcliff, 1993; Lulseged and Vlek, 2005). As compared to flat areas, soil erosion at the steep areas has high adverse effects (Taye et al, (2013) and Descheemaeker et al, (2006). In Ethiopian highlands 23400 million metric tons soil is lost per year (FAO, 1984; Hurni, 1993)

Methods

Findings

Discussion

Conclusion