scholarly journals Effects of climate change on water resources in the upper Blue Nile Basin of Ethiopia

Heliyon ◽  
2018 ◽  
Vol 4 (9) ◽  
pp. e00771 ◽  
Author(s):  
Vincent Roth ◽  
Tatenda Lemann ◽  
Gete Zeleke ◽  
Alemtsehay Teklay Subhatu ◽  
Tibebu Kassawmar Nigussie ◽  
...  
Author(s):  
Gebiyaw Sitotaw Takele ◽  
Geremew Sahilu Gebre ◽  
Azage Gebreyohannes Gebremariam ◽  
Agizew Nigussie Engida

Abstract This study aims to assess the impact of climate change on the water resources of the Upper Blue Nile basin using an integrated climate and hydrological model. The impact of climate change on water resources is being assessed using the regional climate model (RCM) under the representative concentration pathway (RCP4.5 and RCP8.5) scenarios and the Soil and Water Assessment Tool (SWAT) hydrological model. Future climate scenarios have been developed for the 2030s (2021–2040) and the 2050s (2041–2060). The study found that the projected rainfall shows a decreasing trend and is not statistically significant, while the temperature shows an increasing trend and is statistically significant. Due to the sharp rise in temperature, the annual evapotranspiration increased by about 10.4%. This and the declining trend of rainfall will reduce streamflow up to 54%, surface runoff up to 31%, and water yield up to 31%. Climate change causes seasonal and annual fluctuations in the water balance components. However, the projected seasonal changes are much greater than the annual changes. Therefore, the results of this study will be useful to basin planners, policymakers, and water resources managers in developing adaptation strategies to offset the adverse effects of climate change in the Upper Blue Nile basin.


2016 ◽  
Vol 139 (2) ◽  
pp. 229-243 ◽  
Author(s):  
Moges B. Wagena ◽  
Andrew Sommerlot ◽  
Anteneh Z. Abiy ◽  
Amy S. Collick ◽  
Simon Langan ◽  
...  

Precipitation over the Upper Blue Nile Basin in Ethiopia contributes with 85% of the Nile river which provides 93% of Egypt’s conventional water resources. This study aims at assessing the meteorological drought in different locations in the Upper Blue Nile Basin and their relationship with the hydrological drought of Nile river in Egypt. The metrological drought was calculated by the Standard Precipitation Index (SPI) at five stations inside and close to the Upper Blue Nile Basin in Ethiopia, whereas the hydrological drought was calculated by the Streamflow Drought Index (SDI) at Dongola station at Nasser lake entrance. Both indices were calculated using the Drought Indices Calculator (DrinC) software. The selected study period was from 1973 to 2017 based on the availability of recorded data for meteorological stations in Ethiopia, and the streamflow for Dongola station. The data was categorized for each station by considering time periods of 1, 3, 6, 9, and 12 months based on their homogeneity. The correlation between SPI and SDI was evaluated using the Pearson correlation coefficient. The results showed a correlation between SPI for the five stations in the Upper Blue Nile Basin and SDI for Dongola station, where Gore station represented the highest frequency of significance at different time scales especially at the 3-months’ scale. The results confirm the relationship between SPI at Gore Station and SDI at Dongola Station, which means that the hydrological drought in Egypt is highly affected by the meteorological drought in the area surrounding Gore station. The paper recommends improving techniques for monitoring and overseeing drought hazards and assessing more meteorological stations to accurately predict climate change variations in Upper Blue Nile Basin and its effect on Egypt’s water resources.


2013 ◽  
Vol 10 (6) ◽  
pp. 7857-7896 ◽  
Author(s):  
M. T. Taye ◽  
P. Willems

Abstract. Methods from two statistical downscaling categories were used to investigate the impact of climate change on high rainfall and flow extremes of the upper Blue Nile basin. The main downscaling differences considered were on the rainfall variable while a generally similar method was applied for temperature. The applied downscaling methods are a stochastic weather generator, LARS-WG, and an advanced change factor method, the Quantile Perturbation Method (QPM). These were applied on 10 GCM runs and two emission scenarios (A1B and B1). The downscaled rainfall and evapotranspiration were input into a calibrated and validated lumped conceptual model. The future simulations were conducted for 2050s and 2090s horizon and were compared with 1980–2000 control period. From the results all downscaling methods agree in projecting increase in temperature for both periods. Nevertheless, the change signal on the rainfall was dependent on the climate model and the downscaling method applied. LARS weather generator was good for monthly statistics although caution has to be taken when it is applied for impact analysis dealing with extremes, as it showed a deviation from the extreme value distribution's tail shape. Contrary, the QPM method was good for extreme cases but only for good quality daily climate model data. The study showed the choice of downscaling method is an important factor to be considered and results based on one downscaling method may not give the full picture. Regardless, the projections on the extreme high flows and the mean main rainy season flow mostly showed a decreasing change signal for both periods. This is either by decreasing rainfall or increasing evapotranspiration depending on the downscaling method.


2018 ◽  
Vol 560 ◽  
pp. 407-423 ◽  
Author(s):  
Yihun Taddele Dile ◽  
Sirak Tekleab ◽  
Essayas K. Ayana ◽  
Solomon G. Gebrehiwot ◽  
Abeyou W. Worqlul ◽  
...  

2019 ◽  
Vol 11 (4) ◽  
pp. 1539-1550 ◽  
Author(s):  
Gebre Gelete ◽  
Huseyin Gokcekus ◽  
Tagesse Gichamo

Abstract Climate change alters the spacial and temporal availability of water resources by affecting the hydrologic cycle. The main objective of this paper is to review the climate change effect on the water resources of the Blue Nile River, Ethiopia. The impact of climate change on water resources is highly significant as all natural ecosystems and humans are heavily dependent on water. It alters precipitation, temperature, and streamflow of the Blue Nile river basin which is threatening the lives and livelihoods of people and life-supporting systems. Rainfall within the Blue Nile river basin is highly erratic and seasonal due to it being located in the inter-tropical convergent zone. The temperature and sediment load are shown to increase in the future while the rainfall and streamflow are decreasing. The Blue Nile basin is characterized by highly erosive rainfall, erodible soil, and shrinking forest cover. Therefore, mitigation and adaptation measures should be applied by considering these characteristics of the basin. Watershed management methods like afforestation and water conservation are recommended to reduce the impact on the Blue Nile basin.


2014 ◽  
Vol 18 (12) ◽  
pp. 5149-5167 ◽  
Author(s):  
M. Dessie ◽  
N. E. C. Verhoest ◽  
V. R. N. Pauwels ◽  
T. Admasu ◽  
J. Poesen ◽  
...  

Abstract. Understanding runoff processes in a basin is of paramount importance for the effective planning and management of water resources, in particular in data-scarce regions such as the Upper Blue Nile. Hydrological models representing the underlying hydrological processes can predict river discharges from ungauged catchments and allow for an understanding of the rainfall–runoff processes in those catchments. In this paper, such a conceptual process-based hydrological model is developed and applied to the upper Gumara and Gilgel Abay catchments (both located within the Upper Blue Nile Basin, the Lake Tana sub-basin) to study the runoff mechanisms and rainfall–runoff processes in the basin. Topography is considered as a proxy for the variability of most of the catchment characteristics. We divided the catchments into different runoff production areas using topographic criteria. Impermeable surfaces (rock outcrops and hard soil pans, common in the Upper Blue Nile Basin) were considered separately in the conceptual model. Based on model results, it can be inferred that about 65% of the runoff appears in the form of interflow in the Gumara study catchment, and baseflow constitutes the larger proportion of runoff (44–48%) in the Gilgel Abay catchment. Direct runoff represents a smaller fraction of the runoff in both catchments (18–19% for the Gumara, and 20% for the Gilgel Abay) and most of this direct runoff is generated through infiltration excess runoff mechanism from the impermeable rocks or hard soil pans. The study reveals that the hillslopes are recharge areas (sources of interflow and deep percolation) and direct runoff as saturated excess flow prevails from the flat slope areas. Overall, the model study suggests that identifying the catchments into different runoff production areas based on topography and including the impermeable rocky areas separately in the modeling process mimics the rainfall–runoff process in the Upper Blue Nile Basin well and yields a useful result for operational management of water resources in this data-scarce region.


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