REAL TIME OPERATION OF MULTI-PURPOSE RESERVOIR (THE CASE OF GENALE DAWA DAM-3)

Abstract

Reservoir operation has become a major focus of water resources planning and management. Traditionally, reservoir operation is based on heuristic procedures, embracing rule curves and, to a certain extent, subjective judgements by the operator. Water use involves a large number of stakeholders with different objectives, and real time operation is expected to provide balanced solutions between often conflicting objectives. The study area is the Genale Dawa dam3 catchment situated at the Genale Dawa River Basin in Ethiopia. The objective of this study is to develop real time operation of multi-purpose reservoirs and to evaluate suitability of GD-3 sub-basin for surface irrigation development. In this study, CMORPH satellite rainfall product was used for streamflow forecasting using Artificial Neural Network (ANN) model. Real-time operation was performed taking real- time and forecast information about reservoir levels, reservoir inflows and water demands into account using MODSIM model. The result shows that the average energy generated by GD-3 plant is 1,962.24GWh/yr, which is greater than the average energy in the feasibility study for GD-3 hydropower plant, 1640.0 GWh/yr by an amount of 322.24GWh/yr and annual volume of water about 3648.7 Mm3 will be released for downstream water requirement through the controlled outlets. This volume of water has the capacity to use for irrigation since the suitability model revealed that about 55.83% (136138.2ha) of lands in the sub basin were in the range of highly suitable to marginally suitable for surface irrigation development.