scholarly journals Impact of climate change on the hydrology of Blue Nile basin, Ethiopia: a review

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.

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.


Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1762 ◽  
Author(s):  
Nathan Rickards ◽  
Thomas Thomas ◽  
Alexandra Kaelin ◽  
Helen Houghton-Carr ◽  
Sharad K. Jain ◽  
...  

The Narmada river basin is a highly regulated catchment in central India, supporting a population of over 16 million people. In such extensively modified hydrological systems, the influence of anthropogenic alterations is often underrepresented or excluded entirely by large-scale hydrological models. The Global Water Availability Assessment (GWAVA) model is applied to the Upper Narmada, with all major dams, water abstractions and irrigation command areas included, which allows for the development of a holistic methodology for the assessment of water resources in the basin. The model is driven with 17 Global Circulation Models (GCMs) from the Coupled Model Intercomparison Project Phase 5 (CMIP5) ensemble to assess the impact of climate change on water resources in the basin for the period 2031–2060. The study finds that the hydrological regime within the basin is likely to intensify over the next half-century as a result of future climate change, causing long-term increases in monsoon season flow across the Upper Narmada. Climate is expected to have little impact on dry season flows, in comparison to water demand intensification over the same period, which may lead to increased water stress in parts of the basin.


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