Soil Erosion Estimation and Watershed Prioritization in Kulfo Watershed, Ethiopia

doi:10.7176/jnsr/10-1-01

Abstract

Soil loss by runoff is a severe and continuous environmental and infrastructural problem in Kulfo watershed. Deforestation and improper cultivation have resulted in accelerated soil erosion. Information on soil loss is essential to support agricultural productivity and watershed management. Thus, study was aimed to estimate and map the soil loss by using GIS and RUSLE techniques raster format in GIS environment. Topographic map of 1:250,000 scale. Aster Digital Elevation Model (DEM) of 30 m spatial resolution. Digital soil map of 1:250.000 scales, fifteen years rainfall records of six stations nearby watershed and land sat imagery (ETM+) with spatial resolution of 30m were used to derive RUSLE's soil loss parameter. The RUSLE parameters were analyzed and superimposed using raster calculator in the geo-processing tools in ArcGIS10.2 environment to estimate and map the annual soil loss of the study area. The result showed that the mean annual soil loss of the watershed range from none significant (0 tons ha -1 y -1 ) to highly sever (253.38 ton ha -1 y -1 ). The mean annual soil loss of the whole watershed was 88.57 tons ha -1 y -1 . The total annual soil loss in the watershed was 3,862,077 ton per year from 39900 ha of land. The soil erosion affected is spatially situated in the upper steepest slope part and middle part of the watershed. This area where acrisols with high soil Erodibility character are dominant Hence, Slope gradient and length followed by soil Erodibility factors were found to be the main factors of soil erosion .The morphological character also the determinant factor for soil and water conservation practice. Thus, sustainable soil and water conservation practices should be adopted in the most sever area of the watershed. Keyword s : Geographical Information System, Erosion, RUSLE, watershed prioritization DOI : 10.7176/JNSR/10-1-01 Publication date: January 31 st 2020

Highlights

Soil is the top layer of the earth’s crust that is capable of sustaining life
In this study, Revised Universal Soil Loss Equation ( RUSLE) was used to estimate the average annual soil loss which is expressed as mass per unit are a per year.The RUSLE was applied in ArcGIS
Parameter values of RUSLE soil erosion factors were generated in ArcGIS 10.2

Summary

Introduction

Soil is the top layer of the earth’s crust that is capable of sustaining life. It is very important to farmers, who depend on it to provide abundant and healthy crops each year. One major problem in agriculture is soil erosion. Water, ice, animals and the use of tools by manure usually the main agents of soil erosion. It is a natural process which usually does not cause any major problems unless accelerated by human activities. The use of inappropriate farming methods can lead to erosion and limit the productive capacity of the soil (Lal, 2001). Inappropriate crop farming and animal husbandry practice in Kulfo watershed has led excessive soil erosion in some parts and pollution of Chamo Lake at downstream of the watershed. The study of soil erosion in Kulfo watershed is required for planning sustainable management of land resource and water resource development. Based on the (FAO-UNESCO) global digital soil map (FAO, 1985), the global data set of soil properties has been made available by the Data and Information System (DIS) frame work activity of the International Geosphere-Biosphere Programmer (IGBP) (Scholes et al.,1995)

Methods

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Discussion

Conclusion