ASSESSMENT OF WATER RESOURCE AND FORECASTING WATER DEMAND USING WEAP MODEL IN BELES RIVER, ABAY RIVER BASIN, ETHIOPIA

As water is vital for life, analysis of water supply and demand in the basin is necessary.
This will enable to formulate water allocation strategies and allocation principles for
present and future planning. In this paper assessment of water supply and demands was
modeled using the Water Evaluation and Planning model. The parameter Estimation Tool
was used to calibrate and validate the model. Future water demand was estimated using
four different scenarios namely Scenario-I: high population growth, Scenario-II: Dangur
hydropower, Scenario-III: Expansion of irrigation activities and Industries in Beles
basin, and Scenario-IV: combination of scenario-I, scenario-II and scenario-III
Simultaneously. According to the result obtained from the model, the total estimated
mean annual surface runoff that leaves the basin is 5858.6 MCM, the estimated mean
annual actual evapotranspiration is 10017.13 MCM, the estimated mean annual
precipitation is 17525.33 MCM, mean annual interflow is 962.37 MCM, mean annual
Base flow is 480.82 MCM, and mean annual flow to groundwater is 206.40 MCM. Total
available annual streamflow including the Tana-Beles hydropower scheme is 10.03
BCM.