GERD Study: Sediment Trapping May Prolong Sudan's Roseires Dam But Raise Ecological Risks

(MENAFN- Daily News Egypt) A new scientific study has found that Ethiopia's Grand Ethiopian Renaissance Dam (GERD) will trap the vast majority of sediment carried by the Blue Nile, significantly reducing silt accumulation in Sudan's Roseires reservoir and potentially extending its lifespan.

The research, published in Journal of Hydrology: Regional Studies, was conducted by experts from IHE Delft in the Netherlands, the University of Khartoum, and Dutch institute Deltares. Using Delft3D hydrodynamic modelling, sediment-trapping formulas, and artificial neural networks to reconstruct historical data from 1981–2022, the team validated their findings against bathymetric surveys of Roseires.

Results suggest GERD will retain between 92% and 97% of incoming sediment, depending on the model used. While this means the GERD reservoir itself could gradually lose about 0.28% of its storage annually-around 189 million cubic metres of silt-its immense 74-billion-cubic-metre capacity would cushion the impact for decades.

For Sudan, the benefits could be immediate. Sedimentation at Roseires, which has been eroding about 0.26% of its storage each year, may drop to just 0.01% once GERD is fully operational. That reduction could ease dredging costs and prolong the dam's effective service life.

But researchers caution that the changes come with trade-offs.“The anticipated improvement at Roseires does not eliminate challenges,” said co-author Ahmed El-Tayeb.“Depriving floodplains of nutrient-rich silt may affect soil fertility, and shifts in river morphology downstream remain a real possibility.”

The study underscores the importance of cross-border coordination among Ethiopia, Sudan, and Egypt. The authors call for joint reservoir management, basin-wide sediment monitoring, and transparent data sharing to manage new risks and ensure benefits are fairly distributed.

Ultimately, the findings highlight a complex balance: GERD's sediment-trapping could secure engineering and maintenance gains for Sudan, while raising fresh questions for agriculture, ecology, and long-term river health. The authors stress that only cooperative management can turn this trade-off into a sustainable win for all Nile Basin countries.

MENAFN13092025000153011029ID1110057755