Would Africa's largest hydropower dam have profound environmental impacts?

Area of Science:

• Environmental Science
• Hydrology
• Climate Change

Background:

• The Grand Ethiopian Renaissance Dam (GERD) is a major hydropower project on the Nile River, sparking regional and international attention.
• Ongoing negotiations focus on water availability and agriculture, overlooking potential environmental consequences.
• Large dams worldwide present diverse ecological and climate-related risks.

Purpose of the Study:

• To highlight the environmental impacts of the GERD, addressing a gap in current discourse.
• To analyze potential ecological and climate implications based on GERD's characteristics and global dam knowledge.
• To advocate for integrating environmental considerations into GERD planning and operation.

Main Methods:

• Review of scientific literature on environmental impacts of large dams globally.
• Analysis of GERD's specific characteristics (location, size, reservoir depth, intake depth).
• Synthesis of potential impacts on hydrology, biodiversity, greenhouse gas emissions, and local climate.

Main Results:

• Hydrological alterations may negatively affect downstream aquatic life (fish, plants, biodiversity) through changes in water temperature, salinity, and oxygen.
• The GERD's reservoir may intensify greenhouse gas emissions due to its tropical location and deep intakes, though reservoir depth could mitigate this.
• Increased surface evaporation could lead to higher local precipitation and humidity, with potential transboundary ecological, agricultural, and health implications.

Conclusions:

• The GERD's environmental impacts, including effects on biodiversity and greenhouse gas emissions, warrant serious consideration.
• Transboundary ecological, agricultural, and health implications must be evaluated alongside the dam's energy benefits.
• A comprehensive assessment integrating environmental factors is crucial for sustainable management of the GERD.