An investigation of the Mosul reservoir system within the Tigris river basin in Iraq was conducted to determine the ability of the system to generate hydroelectric power. A reproduction model utilizing the Simulink environment on the MATLAB platform was used to imitate the Mosul reservoir system. The reliability of the system under various future scenarios of data sources was also examined by employing a stochastic model used to create an inflow time series. The Thomas–Fiering model was chosen for this reason, which provided a wide range of data sources (inflows) to generate hydropower from the reservoir system under examination. Generally, the annual potential capacity of the Mosul basin for energy generation reaches 20,000 GW·h–1. Realizing that Iraq’s energy requirements are approximately 12 GW of power, and the integrating power production of the basin under examination is about 1.5 GW, this would cover around 12% of the total demand, which is significant.