Impacts of land use/land cover and climate changes on soil erosion in Muga watershed, Upper Blue Nile basin (Abay), Ethiopia

Abstract

Background Soil erosion is one of the major threats in the Ethiopian highlands. In this study, soil erosion in the Muga watershed of the Upper Blue Nile Basin (Abay) under historical and future climate and land use/land cover (LULC) change was assessed. Future LULC was predicted based on LULC map of 1985, 2002, and 2017. LULC maps of the historical periods were delineated from Landsat images, and future LULC was predicted using the CA–Markov chain model. Precipitation for the future period was projected from six regional circulation models. The RUSLE model was used to estimate the current and future soil erosion rate in Muga watershed. Results The average annual rate of soil erosion in the study area was increased from about 15 t ha−1 year−1 in 1985 to 19 t ha−1 year−1 in 2002, and 19.7 t ha−1 year−1 in 2017. Expansion of crop cultivation and loss of vegetation caused an increase in soil erosion. Unless proper measure is taken against the LULC changes, the rate of soil loss is expected to increase and reach about 20.7 t ha−1 year−1 in 2033. In the 2050s, soil loss is projected to increase by 9.6% and 11.3% under RCP4.5 and RCP8.5, respectively, compared with the baseline period. Thus, the soil loss rate is expected to increase under both scenarios due to the higher erosive power of the future intense rainfall. When both LULC and climate changes act together, the mean annual soil loss rate shows a rise of 13.2% and 15.7% in the future under RCP4.5 and RCP8.5, respectively, which is due to synergistic effects. Conclusions The results of this study can be useful for formulating proper land use planning and investments to mitigate the adverse effect of LULC on soil loss. Furthermore, climate change will exacerbate the existing soil erosion problem and would need for vigorous proper conservation policies and investments to mitigate the negative impacts of climate change on soil loss.

Spatial modeling of soil loss as a response to land use-land cover change in Didessa sub-basin, the agricultural watershed of Ethiopia

“…Over the last two-three decades, human activities have often been inclined to intensify soil erosion, thereby creating serious environmental impacts by negatively affecting agricultural productivity, particularly in the last two decades. In recent years, many researchers have highlighted soil erosion due to the effects of human disturbance, which continues to pose severe threats to human sustenance [ [9] , [10] , [11] , [12] , [13] , [14] ]. On a global scale, more than 10 million ha of global cropland are lost annually [ 15 ], though the rate at which it affects soil resources varies with human activities throughout the regions.…”

Mapping of Soil Water Erosion and Prioritization of Conservation Measures in the Noun Watershed (West Cameroon Highlands)

“…First, the tolerable soil loss limit of 11 t/ha/yr for tropical mountain landscapes [6] was adopted to discriminate areas that exceed the tolerable soil loss limit and require special conservation measures. Second, 5 erosion intensity classes were defined based on the classification of [38] and taking into account the tolerable limit of 11 t/ha/year [6]. [38] Four classes of erosion intensity for mountainous and heterogeneous basins based on annual soil loss was distinguished: (a) very severe (>50 t/ha/yr), (b) severe (40-50 t/ha/yr), (c) moderate to severe (20-40 t/ha/yr), (d) low to moderate (<20 t/ha/yr).…”

“…Second, 5 erosion intensity classes were defined based on the classification of [38] and taking into account the tolerable limit of 11 t/ha/year [6]. [38] Four classes of erosion intensity for mountainous and heterogeneous basins based on annual soil loss was distinguished: (a) very severe (>50 t/ha/yr), (b) severe (40-50 t/ha/yr), (c) moderate to severe (20-40 t/ha/yr), (d) low to moderate (<20 t/ha/yr).…”

Statistical and SWAT Model-Based Performance Evaluation of RCMs in Modeling Streamflow and Sediment Yield at Upper Awash Sub-Basin, Ethiopia

“…is study assesses and prioritizes the performance of regional climate models, namely RACMO22T, CCLM4-8-17, HIRHAM5, and RCA4 in simulating climate variables to develop streamflow and sediment yield models. e minor changes in climatic variables can lead to significant changes in the water cycle, which subsequently cause big changes to streamflow and sediment yield [29,30]. e main innovative part of this study was the incorporation of both statistical tools and the SWATmodel to assess the performance of RCMs in the simulation of climate variables, streamflow, and sediment yield variation in a wide watershed concerning the observed inputs [31].…”