Repeated games, an important mathematical formalism, open attractive perspectives in the modeling and studying of interactions between multiple self-interested parties (individuals or groups). The main conceptual difference between static, and repeated and dynamic games is that the former have a preset, finite number of turns, while the latter can potentially last forever and end only with a decision by a player, or by chance. Unlike previous surveys of repeated games, which originated mainly from the economics research community, the performances of repeated games were investigated in this study for evaluating the time required to flush a reservoir, taking account of water quantity and quality. A sediment-flushing model was developed to estimate the flushed sediment and water volumes, and operating period of flushing, to be taken into account in the reservoir simulation model. Dez Hydropower Reservoir in Iran was chosen as the case study for applying the proposed methodology. The results show that the methodology provides an effective and useful tool for reservoir operation.