Abstract
Information on soil loss and sediment export is essential to identify hotspots of soil erosion to inform conservation interventions in a given watershed. This study investigates the dynamics of soil loss and sediment export associated with land-use/land cover changes and identifying soil loss hotspot areas in the Winike watershed of the Omo-Gibe Basin of Ethiopia. Spatial data collected from satellite images, topographic maps, meteorological and soil data were analyzed. The land-use types in the study area were categorized into six: cultivated land, woodland, forest, grazing, shrubland, and bare land. The Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) of the sediment delivery ratio (SDR) model was used based on the analysis of land use/land cover and RUSLE factors. The results show that total soil loss increased from 774.86 thousand tons in 1988 to 951.21 thousand tons in 2018 while the corresponding sediment export increased by 3.85 thousand tons for the same period. These were subsequently investigated in each land-use type. Cultivated fields generated the highest soil erosion rate, increasing from 10.02 t/ha/year in 1988 to 43.48 t/ha/year in 2018 when compared with the grazing, shrub, forest, wood land and bare land-use types. This corresponds with the expansion of the cultivated area. This is logical as the correlation between soil loss and sediment delivery and expansion of cultivated area is highly significant (p < 0.001). Sub-watershed six (SW-6) showed the highest soil loss (23.17 t/ha/year) while sub-watershed two (SW- 2) has the lowest soil loss (5.54 t/ha/year). This is because SW-2 is situated in the lower reaches of the watershed under dense vegetation cover experiencing less erosion. The findings on the erosion hotspots presented in this study allow prioritizing the segments of the watershed that need immediate application of improved management interventions and informed decision-making processes.
Highlights
Information on soil loss and sediment export is essential to identify hotspots of soil erosion for conservation interventions in a given watershed
Many research reports show that land use/land cover change result in soil erosion and sedimentation processes that disrupt the hydrological balance of a watershed, e.g, Chaleleka wetland, Central Rift Valley of Ethiopia (Wolka et al, 2015) and the level of Hawassa lake has increased due to erosion and the sedimentation processes in the surrounding river watersheds (Ayenew et al, 2007; Kebede et al, 2014)
The IntegratedValuation of Ecosystem Services and Tradeoffs (InVEST) model analysis indicated that a historical fluctuation of soil loss and sediment export due to the considerable conversion of land use/land cover changes
Summary
Information on soil loss and sediment export is essential to identify hotspots of soil erosion for conservation interventions in a given watershed. Speedy land-use alteration because of exhaustive agronomic practices, population pressure, poverty, the absence of comprehensive land-use policies and land tenure systems upshots intensifying rates of soil erosion (Abebe and Sewnet, 2014; Aster, 2004; Tefera et al, 2002). This soil loss is activated by an amalgamation of topographic factors such as slope length and steepness, and climate change along with land cover patterns and the intrinsic properties of soil (Gelagay and Minale, 2016). Many research reports show that land use/land cover change result in soil erosion and sedimentation processes that disrupt the hydrological balance of a watershed, e.g, Chaleleka wetland, Central Rift Valley of Ethiopia (Wolka et al, 2015) and the level of Hawassa lake has increased due to erosion and the sedimentation processes in the surrounding river watersheds (Ayenew et al, 2007; Kebede et al, 2014)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
