Evaluation of the Impacts of Climate Change on Sediment Yield from the Logiya Watershed, Lower Awash Basin, Ethiopia

Abstract

It is anticipated that climate change will impact sediment yield in watersheds. The purpose of this study was to investigate the impacts of climate change on sediment yield from the Logiya watershed in the lower Awash Basin, Ethiopia. Here, we used the coordinated regional climate downscaling experiment (CORDEX)-Africa data outputs of Hadley Global Environment Model 2-Earth System (HadGEM2-ES) under representative concentration pathway (RCP) scenarios (RCP4.5 and RCP8.5). Future scenarios of climate change were analyzed in two-time frames: 2020–2049 (2030s) and 2050–2079 (2060s). Both time frames were analyzed using both RCP scenarios from the baseline period (1971–2000). A Soil and Water Assessment Tool (SWAT) model was constructed to simulate the hydrological and the sedimentological responses to climate change. The model performance was calibrated and validated using the coefficient of determination (R2), Nash–Sutcliffe efficiency (NSE), and percent bias (PBIAS). The results of the calibration and the validation of the sediment yield R2, NSE, and PBIAS were 0.83, 0.79, and −23.4 and 0.85, 0.76, and −25.0, respectively. The results of downscaled precipitation, temperature, and estimated evapotranspiration increased in both emission scenarios. These climate variable increments were expected to result in intensifications in the mean annual sediment yield of 4.42% and 8.08% for RCP4.5 and 7.19% and 10.79% for RCP8.5 by the 2030s and the 2060s, respectively.

Land cover change and its implication to hydrological regimes and soil erosion in Awash River basin, Ethiopia: a systematic review

“…Awash Basin Authority 2017 reports and strategic plan and five articles (Abebe & Gebremariam, 2019;Jilo et al, 2019;Naqvi et al, 2019;Tibebe & Bewket, 2011;Zeberie, 2020) were chosen to assess land cover impacts on sediment loss. The literature employed various techniques to detect land cover and its relation with hydrological regimes (Fig.…”

“…The upstream changes on the lower basin impacting water resource availability for agriculture production, frequent flood, drought, and sedimentation are apparent. Besides anthropogenic activities, sediment loss under climate change scenario impact is demonstrated in the Lower basin (Jilo et al, 2019). From the highland toward the lower of the Adama watershed (part of the Upper ARB), it mainly consists of the bush, scrub, and grassland potentially susceptible to high soil erosion loss (Naqvi et al, 2019).…”

SWAT model-based quantification of the impact of land use change on sediment yield in the Fincha watershed, Ethiopia

“…Due to the lack of continuous sediment data, these were derived by applying an empirical sediment rating curve to the simulated daily stream flow. Such an approach is generally used when there are few long-term and trustworthy records of sediment concentrations (Jilo et al, 2019).…”

“…The NSE values can reach a maximum of 1 (perfect fit), while a negative NSE value indicates that the model's performance is inferior to that obtained using the observations' mean as a predictor (Jilo et al, 2019). The simulation efficiency is classified as unsatisfactory, satisfactory, good, or very good if NSE<0.50, 0.5<NSE<0.65, 0.65<NSE<0.75, 0.75<NSE<1, respectively .…”

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

“…us, it is very important to evaluate climate variability's impact on water and sedimentation using various RCMs to map and prepare adaptation options [13,14]. Especially, incorporating a climate model by considering its performance in precipitation and temperature simulations is very important to pave the way for further study and understanding of climate change's impacts on surface runoff, sediment yield, and groundwater [15,16]. e development of a new RCM leads to another opportunity for scientists to analyze the effects of climate change in a discrete manner that relies on a regional rather than global context [17,18].…”