Filling Africa’s largest dam puts political tension at risk if engineering realities are ignored

A hydroelectric dam currently under construction in Ethiopia is expected to be the largest hydroelectric plant in Africa, but could be headed for controversy over international agreements on water exchange.

New research from a consortium led by the University of Manchester notes that some negotiated strategies to fill Ethiopia’s new Grand Ethiopian Renaissance Dam (GERD) might not be feasible in critical river flow conditions due to the limited capacity of the dam. to release water at low levels. .

The team led by the University of Manchester argues that the dam’s possible inability to follow an eventual international agreement could create controversy and complicate future efforts to share water and electricity in East Africa.

The GERD dam, a large hydroelectric dam with an installed capacity of 5,150 megawatts, is under construction on the Blue Nile in Ethiopia. Construction began almost a decade ago and when completed, the GERD will be the largest hydroelectric plant in Africa and the 10th largest in the world.

The main objective of the dam is national and regional electrification and is expected to improve access to electricity in East Africa through existing and planned electrical interconnections. But achieving the benefits will require filling the associated reservoir while retaining water that would otherwise have flowed downstream.

The volume of the GERD reservoir is about 1.5 times the average annual flow of the Blue Nile. This means filling it all at once is out of the question, as it would prevent the water from flowing downstream and deplete most of the Nile River.

The debate over filling the GERD has been ongoing since the dam was announced. Negotiations between Ethiopia, Sudan and Egypt on the initial filling of the reservoir and the long-term operation of the GERD took place in Washington in November 2019 to February 2020.

The Manchester team say that consideration of engineering limitations due to the design and construction of the dam should inform negotiations on initial filling of the reservoir to help prevent unnecessary political tensions later on.

First author of the new research, Ph.D. Mohammed Basheer, a Manchester University student and winner of the Dean’s Award for Science and Engineering, says: “Because the design and construction of the Great Ethiopian Renaissance Dam on the Nile was carried out prior to a cross-border agreement , ongoing negotiations between the Ethiopians and Sudanese, and the Egyptian governments on the initial filling and long-term operation of the dam must consider the engineering features of the dam exits. “

The African Union convened new negotiations in July and August 2020. No agreement has been reached, but several proposals have been made and discussed. So far, the negotiations have not fully recognized the engineering requirements of the dam, including the hydraulic capacity of the dam’s outlets, which determines how much water it can release.

Lead Lead Author Professor Julien Harou, Professor of Water Engineering at the University of Manchester, comments: “Ethiopia, Sudan and Egypt are at a crossroads in their ability to collaboratively manage limited and stressed water resources. Of the East Nile. Preventing potential predictable sources of containment will help the three countries avoid political tensions and lay the foundation for regional trust, collaboration and prosperity. ”