The construction of the Grand Ethiopian Renaissance Dam (GERD) is transforming water infrastructure in the Nile Basin. While the dam offers potential electricity improvements for Ethiopia and its neighbors, operational consensus among Ethiopia, Sudan, and Egypt remains elusive. This paper introduces a coevolutionary modeling framework simulating the Nile River system and Egypt's macroeconomy, highlighting dynamic feedbacks between them. The framework demonstrates that a coordinated operating strategy for the GERD can meet water demands in Egypt during scarcity, while boosting hydropower generation and storage in Ethiopia during high flows. This coordinated strategy is compared to a strategy resembling a recent draft proposal, revealing the hydrological and macroeconomic advantages of collaboration.

Mohammed Basheer, Victor Nechifor, Alvaro Calzadilla, Khalid Siddig, Mikiyas Etichia, Dale Whittington, David Hulme, Julien J. Harou