WATER SUPPLY DEMAND ANALYSIS USING WEAP MODEL IN UPPER BILATE WATERSHED, RIFT-VALLEY LAKES BASIN, ETHIOPIA

Abstract

Global water demand will primarily grow due to population and economic growth, rapid urbanization and increasing demand for food and energy. The main objective of this thesis is to model the water resources of the upper Bilate River Basin for supply demand analysis under climate change and future development scenarios using WEAP Model. The annual activity level, annual water use rate, and supply and demand data are used to analysis the current and future water demands and supply. WEAP model was used to model the current condition of water supply and demands and also to create scenarios for future water demands and supply. Water balance study of Upper Bilate River Basin in the current account year was managed by using the technique of water supply, demand and unmet demand. Accordingly, total unmet demand of Upper Bilate River basin in the current account year (2020) is. 12.72Mm³/sec. The results of this analysis shown the study found no quantity of unmet demand in the reference scenario (1990 - 2020) for all demands. Although for the Climate change scenario II for total cumulative water demand of 553.62Mm3/year in both Short term and Long term period 40.87% and 16.81% of the total demand is Unmet in the analysis respectively. Future development scenario is more affect demand site in the upper Bilate catchment than climate change scenario. In general, this study conclude that future water demands, supply and unmet water demands shows an increment in future development and climate change Scenarios due to shortage of crop water requirement, increment of irrigation command area, and increment of consumption rate as well as ever increasing of population growth rate in the Upper Bilate catchment. Alternatives, such as increasing irrigation water use efficiency, building water harvesting dams and developing ground water availability in the watershed were recommended to reduce unmet demands.