Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Planning and Operation of Hydropower Reservoir in Tekeze Basin Considering Hydrological Variability and Climate Change

Auteur : Fikru, Fentaw

Université de soutenance : Addis Ababa University

Grade : DOCTOR OF PHILOSOPHY In CIVIL ENGINEERING 2018

Résumé partiel
Reservoirs are built to manage surface water resources used to balance between water resources and demands. Water in the arid, semi-arid and other climate regions like Ethiopia has available finite, but the demand increases. Hence reservoirs should be optimally operated in this semi-arid area to use water most efficiently. This study was conducted to assess hydrological variability and climate change impacts on the operation of Tekeze hydropower reservoir in Tekeze River basin. In this basin annual and inter-annual climate variability of precipitation and climate change uncertainties are present challenges for water resources planning and management. This study contributed to provide a scientific basis for the changing characteristics of precipitation and streamflow of Tekeze basin. The research is carried out using Mann-Kendall (MK) test and Indicators of Hydrologic Alteration (IHA) to determine the potential trends and variability of rainfall and streamflow. The trend in mean monthly precipitation data shows increasing trends in the South-eastern part of the Tekeze basin whereas decreasing trend in the North-western part of the basin. The streamflow trend analysis also showed a significant increasing trend during wet seasons, in contrast dry season showed a significant decreasing trend. Indicators of Hydrologic Alteration (IHA) used to evaluate hydrologic variables and trends generated from daily streamflow data at Embamadre due to Tekeze hydropower reservoir operation. The significant results in the streams downstream of Tekeze hydropower reservoir had increased minimum flow, decreased maximum flows, decreased rise and fall rates, reduced wet season monthly flow. All these hydro-climatological variability influence Tekeze hydropower reservoirs planning and operation. This would be valuable for the water managers and decision makers to make better decision on integrated water resources management and ecological environment assessment in the future.Assessment of Tekeze River basin water resources undertaken through the application of bias-corrected ensemble COordinated Regional climate Downscaling Experiment in African domain (CORDEX-Africa) Regional Climate Models (RCMs) under Representative Concentration Pathway RCP4.5 and RCP8.5 climate scenarios in the 2020s, 2050s and 2080s used as an input to Soil and Water Assessment Tool (SWAT).This study compares the performance of different bias correction methods successfully, in particular, the result of both precipitation and temperature were greatly improved by the distribution mapping (DM) bias correction.

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