AbstractClimate change affects water resources quality and quantity and water consumption and crop yield through changes in the amount of precipitation and its pattern, temperature, evapotranspiration, erosion, and pollution wash off in a watershed. In this study, a simulation-optimization model was developed by coupling the soil and water assessment tool (SWAT) and nondominated sorting differential evolution (NSDE) algorithm to develop strategies for mitigation and adaptation to climate change. The multiobjective model was applied to maximize agricultural revenue and minimize nutrient discharge to the Minab reservoir. The calibrated and verified model was utilized to estimate future (2021–2099) variables. The annual precipitation and reservoir inflow will decrease by 14% and 46%, respectively. Climate change analysis indicated that the precipitation temporal pattern will change to early fall or late spring. The results of optimization showed that the agricultural revenue increased by 37%, and total nitrogen (TN) load decreased by 70%, compared to the current condition. Also, applying climate change to the optimum strategies could reduce total revenue and TN load by 57% and 41%, respectively.