Nile basin flow regimes under 21^st century climate variability

Area of Science:

• Hydrology
• Climate Science
• Water Resource Management

Background:

• The Nile Basin, crucial for over 300 million people, faces escalating hydrological risks due to climate change and water disputes.
• Existing projections of extreme streamflow events are hampered by fragmented modeling and inadequate climate uncertainty integration.

Purpose of the Study:

• To assess future flood risk in Nile Basin downstream countries.
• To provide basin-wide projections of extreme streamflow events under different climate scenarios.
• To inform coordinated planning and regional cooperation for water security.

Main Methods:

• Utilized a calibrated, climate-driven Soil and Water Assessment Tool (SWAT) model.
• Forced the model with bias-corrected Coupled Model Intercomparison Project Phase 6 (CMIP6) data.
• Analyzed projections under Shared Socioeconomic Pathways (SSP2-4.5) and (SSP5-8.5) scenarios.

Main Results:

• Projected increases in 100-year peak discharges of 63% (SSP2-4.5) and 85% (SSP5-8.5) in the 21st century.
• Indicated that extreme floods could occur almost every decade under high-emission scenarios.
• Highlighted significant flood risk amplification in downstream Nile Basin regions.

Conclusions:

• Climate-driven hydrologic modeling reveals substantial future flood risks in the Nile Basin.
• Emphasized the critical need for coordinated planning and regional cooperation to mitigate flood risks.
• Provided actionable risk information to enhance preparedness and address water security challenges.