The increase of population and socio-economic activities has escalated the water demand for various purposes and put stress on existing water resources across the world, in particular in arid and semi-arid countries. Hence, managing the optimum use of water resources is a crucial issue and it is imperative to adopt realistic policies to ensure water is used more efficiently in various sectors. This paper presents an optimization analysis to determine monthly operating rules for the Doroudzan Reservoir located in southern Iran. Different strategies under limited water availability conditions have been analyzed by running an optimization model based on observed and synthetic inflow data, and the performance indicators of each strategy are presented. Each strategy includes a minimum requirement release in the optimization process and results in a specific operation policy. In this study, LINGO is applied to determine optimum operational parameters and the synthetic inflows are generated using the Monte Carlo simulation method. The results demonstrated that the applied methods could efficiently optimize the current operation policy of an existing reservoir in a single-objective framework.