Grand Ethiopian Renaissance Dam can generate sustainable hydropower while minimizing downstream water deficit during prolonged droughts

Optimizing hydropower generation from the Nile upstream mega-dams during prolonged droughts while minimizing the downstream water deficit is the cornerstone in resolving the ongoing major water conflict in the Eastern Nile River Basin. A decade of negotiation and mediation has been unsuccessful, mainly due to the hydraulic uncertainties associated with operating the Grand Ethiopian Renaissance Dam during prolonged droughts. Based on the negotiation outcomes, we provide comprehensive assessments of the efficiency of multiple drought-mitigation policies for the impact of dam operation. Our results suggest it can generate almost optimal hydropower without a noticeable downstream deficit during wet, average, and temporary drought flow conditions. For prolonged drought, we identify an ideal operation policy allowing the Grand Ethiopian Renaissance Dam to generate a sustainable energy of 87% of its optimal hydropower without generating additional downstream water deficit. Furthermore, we provide four intermediate policies demonstrating enhanced upstream hydropower generation while minimizing dam-induced downstream water deficits. Our findings attempt to bridge the negotiation disparities in the Nile hydropower mega-dams operations during prolonged drought and foster an actionable and collaborative framework. Nile’s river mega-dams can operate collaboratively to generate upstream sustainable hydropower and minimize downstream water deficit during drought events, according to an analysis that combines the water resources systems model and policy scenarios.