System dynamics is a management approach that has been used in recent years for simulating water resources systems. In this study, an attempt was made to simulate the water resources status of the Molla Sadra Dam basin (located in the north of Fars Province, southern Iran) using the system dynamics approach. For this purpose, the economic subsystem, groundwater level fluctuations, groundwater volume changes, surface water, and the overall system were examined using VENSIM software. The performance of the upstream and downstream aquifers of the Molla Sadra Dam and the Molla Sadra Dam reservoir was simulated for the years 2009 to 2020. Accordingly, twelve different scenarios (management options) were proposed. The results of evaluating the different management options showed that if rice cultivation is eliminated and replaced with sesame cultivation, the income of farmers in the downstream area of the Molla Sadra Dam would increase by 54% (Management Option 11). Under this management option, the average annual income of farmers downstream of the dam would be 114 million Tomans. With this management option, it is possible to cultivate the same cultivated areas currently under cultivation in the downstream regions of the dam while consuming less water.