Synthetic streamflow generation for the ungauged Omo Kuraz watershed using MIKE 11 NAM parameter regionalization

Area of Science:

• Hydrology
• Water Resource Management
• Environmental Engineering

Background:

• The Omo-Kuraz Dam watershed in Ethiopia lacks direct streamflow data.
• Accurate streamflow data is essential for effective water resource planning and dam management.

Purpose of the Study:

• To generate synthetic streamflow for the ungauged Omo-Kuraz Dam watershed.
• To assess the performance of the MIKE 11 NAM model in a data-scarce catchment.
• To provide baseline hydrological data for water resource planning in the Omo-Gibe River Basin.

Main Methods:

• Utilized the MIKE 11 NAM conceptual rainfall-runoff model.
• Calibrated and validated the model using data from the downstream Omorate gauging station (2010-2020).
• Integrated the high-resolution CHIRPS satellite dataset for enhanced precipitation analysis.

Main Results:

• The MIKE 11 NAM model demonstrated strong predictive performance with R2 values of 0.84 (calibration) and 0.80 (validation).
• Simulated mean annual discharge for Omo-Kuraz was 324.16 m³/s, contrasting with the regulated Omorate flow of 510.53 m³/s.
• Synthetic streamflow captured a wider natural hydrographic variability (83-2224 m³/s) compared to observed regulated flows.

Conclusions:

• The MIKE 11 NAM framework is a practical tool for streamflow generation in data-scarce catchments.
• The generated synthetic streamflow provides valuable baseline data for water resource planning in the Omo-Gibe Basin.
• Acknowledged uncertainties due to unmodeled reservoir operations and rainfall interpolation.