Declining rainfall, development of agricultural and industrial activities, population growth as well as Iran’s location in arid and semi-arid regions of the planet have led to a shortage of water resources and a lack of supply, especially in low-water years. One of the appropriate solutions in this regard is the optimal operation of available resources as well as its storage and maintenance for critical conditions. In most deterministic optimization techniques, the optimal parameters of reservoir operation are extracted based on a certain series of inflow which cannot be generalized to other series of inflow to the reservoir. In this paper, an operation model based on the Parameterization Simulation- Optimization (PSO) method is utilized in which considering stochastic conditions of inflow, the optimal parameters of rationing are determined via the link of the reservoir simulation model to the NSGA-II multi-objective optimization algorithm. In the mentioned model, the combination of the stochastic data and part of historical data (a total of 4,800 months) are used to optimize the system and extract optimal operation rules. Moreover, to verify the developed model, the combination of the stochastic data and the remaining of historical values (a total of 372 months) are utilized. Finally, the results obtained from the model are compared with those of the standard operating policy (SOP). The result reveals that compared to the SOP, the PSO model based on parameterization of the reservoir works better in managing the allocation of demands in the dry and wet months and preventing the reservoir from emptying.
