This study showed the effectiveness of the proposed model in the management of dam eutrophication. The results indicated that the results of the two models were similiar. Here, the RMSE between the results of the two models for the lower, middle and upper layers of the reservoir is 0.004, 0.007 and 0.010, respectively, and 𝑅2 is 0.91, 0.9 and 0.79. Monte Carlo, Sensitivity Analysis, and Parameter Variation experiments help. Then, by combining the developed model in Anylogic environment with a simulated annealing optimization model, a simulation-optimization model was developed to determine the optimal values of water releases from different layers of reservoir in 15 years’ horizon considering the quantitative and qualitative objectives. AnyLogic was the first tool to introduce multimethod simulation modeling. With 0.98, 0.94, 0.90, 0.93 and 0.97, which shows the high correlation between the results of Anylogic model with the two mentioned models. comparing the presented results with the results of the CE-QUAL-W2 and Vensim simulation models over a one-year period showed that the value of the correlation coefficient (𝑅2) for the variables phosphate, ammonium, nitrate, Dissolved oxygen and Chlorophyll-A between the two models of Anylogic and CE-QUAL-W2 is equal to 0.89, 0.81, 0.78, 0.75 and 0.86, respectively, and the value of this coefficient for the mentioned variables is equal between the two models of Anylogic and Vensim. Thus, the relationships of the elements related to eutrophication were formulated in different layers of Karkheh Dam and in relation to each other in the system dynamics form. In this research, for the first time, a simulation-optimization system dynamic-based model with Anylogic software for reservoir eutrophication management is presented.

Anylogic sensitivity analysis