One of the biggest conflicts in the Middle East and Eastern Africa is brewing over natural resources. In this case—the water from the Nile River and how upstream damming affects the countries Ethiopia, Sudan, and Egypt, and their share of water and hydropower.

A new article in Communications Earth & Environment provides a scientific framework for operating the Nile's "mega" dams during prolonged droughts to balance generating sustainable hydropower while minimizing the water deficit for people living downstream.

The research, co-authored by Essam Heggy, co-principal investigator at the University of Southern California Viterbi School of Engineering Center for Arid and Water Research Exploration (AWARE) within the USC Ming Hsieh Department of Electrical and Computer Engineering, evaluates the efficiency of multiple drought-mitigation policies related to the operations of the Nile's mega-dams.

Most of the Nile River flows originate from the highlands in Ethiopia and flow northward to the lowlands in Egypt and to the Mediterranean. The rising dispute is over what control the dam operators should have over the flowing water during prolonged periods of drought. While Egypt relies on the Nile for water, Ethiopia relies on its newly completed mega-dam, named Grand Ethiopian Renaissance Dam (GERD), for hydroelectric power.

Corresponding author Essam Heggy explains the source of tension as follows, "Nile upstream hydropower dams will bring electricity to 60% of the population of Ethiopia while 98 % of Egypt's annual renewable water resources come from the same river; the upstream is in a dire need for energy and downstream is in a dire need for water."

He adds, "Over a decade of negotiation, no cooperative operation framework has been reached due to the lack of a metric assessment of the mega-dam operations on both the up and downstream interests during prolonged drought (multi-years of drought). These droughts are expected to worsen, causing severe consequences to the river riparian."

The challenge, says Heggy, is to determine how to operate the Grand Ethiopian Renaissance Dam (GERD) during prolonged drought and to accurately predict what the gains and losses are, both up and downstream of the Nile's Dams.

The new paper reframes the notion of prolonged drought and tries to come up with what the authors believe is an ideal operation policy allowing GERD to generate sustainable energy. The framework suggests allowing for ~87% of GERD's optimal hydropower without a dam-induced downstream water deficit for Egypt in the midst of hydro-climatic extremes.

The authors hope to increase the resilience for prolonged droughts to the more than 300 million inhabitants of the Eastern Nile Basin who live under highly uncertain climatic projections.

Heggy and colleagues from Catholic University of Louvain, Northern Michigan University, NARSS and National Research Centre in Egypt, utilized an up-to-date hydraulic model to assess the efficiency of several suggested policies that address the uncertainty around the impacts of upstream dams during prolonged drought. They also looked at 100-year-long historical data and simulated several operations policies to generate sustainable hydropower and minimizing downstream water stress.

Their simulated policies get at the heart of the issue: determining mitigations by better defining prolonged drought condition in the Eastern Nile Basin with one metric: the critical level of the Aswan High Dam. Heggy references other journals to show the competing definitions of drought held by countries in the region.

A new approach to reduce conflict

The Nile in Egypt is fed by two branches: The Blue Nile from the Ethiopian Highlands accounting for more than 80% of the river's flow, and the White Nile from Lake Victoria accounting for the rest.

Heggy and colleagues suggest the following: Instead of only looking to the current flow of the Blue Nile as an indicator of prolonged drought, policymakers should rely on the level of the Aswan High Dam as the indicator of this extreme hydro-climatic condition, coming up with a figure of Aswan High Dam being at 165 meters (~78 billion cubic meters) as the figure at which drought should be declared and the mitigation measures should be activated.

The authors' belief is that this approach can resolve disagreement on what constitutes "dry years" and "flow volume." It also incorporates water budget contributions from the White and Blue Nile flows. In addition, the study's authors outlined what they believe is an optimized policy in which the Grand Ethiopian Renaissance Dam in Ethiopia can still generate sustainable energy of more than 87% of its optimal hydropower without triggering a dam-induced downstream water deficit in Egypt.

Mohamed Ramah, a Ph.D. graduate researcher at Catholic University of Louvain, stated, "Only the metric assessment of both demands of upstream hydropower and downstream water budget can resolve the conflict, not only calling for increasing upstream hydropower dams while undermining downstream water deficit as advocated by scientific interest groups."

Heggy says, "Sharing the Nile's water and hydropower resources under increasingly uncertain climatic forecasts is a wake-up call for policymakers to fight this uncertainty together with open science and bring water and climate research to the level where they can achieve peace and prosperity."