Assessing Rate Of Soil Loss And Sediment Yeild From Tullu Gana Watershed In Horo Guduru Wollega Zone, Ethiopia

Abstract

Currently, soil erosion and sedimentation are the major watershed problems in Ethiopian highland. This study was aimed to assess rate of soil loss and sediment yields for past three decades (1990-2021) from Tullu Gana Watershed in Horo Guduru Wollega Zone, Ethiopia. Rainfall, soil, Digital Elevation Model, Land use and Land cover (LU/LC) data were used as input data sets to generate RUSLE factor values. In this study, integration of RUSLE with GIS environment was used. Spatial data layers of the five factors of RUSLE values were computed using ArcGIS 10.4 software. The Sediment Delivery ratio was determined from drainage area. to estimate sediment yield . The study result showed that, total annual soil loss within the last three decades was 135,882.255 ton yr−1 , whereas total annual sediment yield estimated to be 26089.392 ton yr-1 from 15451.21 hectares. Furthermore, six land use land cover class were recognized and their extents were varies from earliest to recent of study periods. Also, the study area were identified into six critical sub watershed and prioritized based on mean soil loss rate for future conservation planning .From six critical sub watershed, Sw2, Sw4 categorized in very high severity class, Sw3, Sw5, Sw6 categorized in high severity class whereas Sw1 categorized in low severity class. Overall, understanding amount of soil loss and sediment yield and mapping its distribution is an important and effective for identifying erosion prone areas as well as for sustainable land management.Therefore,Tullu Gana Watershed needs immediate intervention for better conservation planning by considering identified priority classes and hotspot areas.