Stage-Based Filling of Grand Ethiopia Renaissance Dam (GERD): Flexible, Adaptive, and Cooperative Approach

Abstract

The initial filling of the Grand Ethiopian Renaissance Dam (GERD) with its storage capacity of 74 BCM has been the concern of downstream countries since its construction in 2011. The three countries (Egypt, Ethiopia, and Sudan) have been negotiating to establish filling and annual operation rules and guidelines within the umbrella of equitable and reasonable water use without causing significant harm, despite no water-sharing agreement of the riparian countries. They also try to use adaptive, cooperative principles as affirmed by signing the declaration of principles in 2015. Researchers formulated various year-based filling strategies considering different hydrological scenarios—however, the traditional fixed year filling plan, non-flexible by its nature, is unable to tackle the problem. The situation motivated the authors to think and to come up with an innovative concept called stage-based filling. Stage-based filling is flexible, adaptive, and cooperative by its nature. Stages neither refer to the flow conditions nor refer to any water-sharing arrangements. They also do not use a fixed filling year or minimum release and can be accelerated or decelerated based on hydrological variability and cooperation. Based on these concepts, there are five filling stages of GERD; the first stage entirely depends on the construction phase, and the others are more flexible to adapt and cooperate with the changes. Unlike previously proposed filling schedules, GERD’s stage-based filling is accepted and adopted by the three countries to solve their concerns. Furthermore, the countries use multiple modeling approaches to evaluate the filling schedule and its impacts according to their perspectives, like using the year of filling, amount of release during filling, energy production, and water level in the reservoir.