A hydrological model called SWAT was used to predict river flow in the Upper Blue Nile basin. The model was calibrated and validated using 10 years of data, showing good performance in simulating observed discharge patterns. The most sensitive parameter was curve number, while the least sensitive was ground water delay time. The model's accuracy was assessed using Nash Sutcliff Efficiency and Coefficient of Determination, with values of 0.71 and 0.66 for calibration. Overall, the SWAT model proved suitable for future scenario analysis in the Upper Blue Nile basin.