This tool coupled a hydrologic model with the Water Evaluation and Planning water-allocation model. It was calibrated and validated by reproducing observed river flows and water stored in the hydropower reservoirs, respectively. It considered the impact of possible future glob+AM235al changes (potentially critical) and the development of upstream small reservoirs (leading to upstream-downstream trade-offs) on the Akosombo hydropower scheme. This tool may foster transboundary dialogue for the integrated management of the basin"s water resources.