امير مولاجو

In this thesis, a simulator for the water, food, and energy (WFE) nexus has been developed. By separating the interrelations (internal relations) of the subsystems from the interactions between the subsystems (external relations), the data in all three WFE subsystems were classified into four general categories: "independent parameters", "independent variables", "management variables", and "nexus variables". The development or expansion of the simulator models includes a combination of modifying or completely designing the simulator models of each subsystem based on the identified interrelations and interactions. The models are designed or modified in such a way that they can be used both independently (stand-alone) and, in line with the goal of this thesis, they can be integrated with each other to achieve a simulator model for the WFE nexus. Based on the identified requirements based on the interrelations and interactions between WFE subsystems, the designed simulation model for the water subsystem includes modules for evaporation simulation, surface water simulation, groundwater simulation, surface water and groundwater interrelation, reservoir operation, return flow, and qualitative simulation. For the crop growth simulator model, the AquaCrop-OSPy model was modified based on the identified requirements. Data from the Sufi Chay sub-basin study area (Maragheh-Bonab plain) was used to eva‎luate and validate the developed WFE nexus simulator model. The Sufi Chay sub-basin is one of the important sub-basins of Lake Urmia, and given the increasing importance of the issues related to the drying up of Lake Urmia and its consequences, it seemed important to focus on this specific geography of Iran. It should be noted that the results of the WFE nexus simulator model were compared with the results of the stand-alone designed water subsystem simulator and the stand-alone modified crop growth simulator model to determine the effect of online modeling of interactions between subsystems. Also, to eva‎luate the efficiency of the designed WFE nexus simulator, the eva‎luation criteria of the coefficient of determination (DC), root mean square error (RMSE), and normalized root mean square error (NRMSE) were calculated for each of the simulator model modules. The results indicated acceptable accuracy of the developed simulator model. Finally, this simulator model was integrated with an optimization model (non-dominated sorting genetic algorithm) to extract Pareto and optimal options. Multi-objective optimization was performed with the goals of reducing water consumption, reducing energy consumption, increasing income, and increasing groundwater storage, and nine Pareto options (S1 to S9) were selected. To select the best option from these nine options, the compromise programming method was used. Finally, option S6, which was one of the options focusing on rainfed cultivation and had the lowest area of irrigated wheat among the options, was selected as the best option. By comparing the best Pareto option (S6) and the historical option (S0), it was observed that the total cumulative area under cultivation decreased by about 47 percent during the simulation period (from 2005 to 2014), and total water consumption and total energy consumption decreased by 51 percent and 39 percent, respectively, during this period. However, the net income produced did not decrease much, so that the cumulative net income of the historical option (S0) is less than 1.5 percent higher than the best Pareto option (S6). The results also showed that the S6 option was able to reduce water and energy consumption by reducing the cultivated area, improve the groundwater level in the region, and provide financial benefits to farmers.

امنيت آب , امنيت غذا , امنيت انرژي , دشت مراغه-بناب , الگوي كشت , رتبه بندي نامغلوب , برنامه ريزي سازشي

Water security , Food security , Energy security , Maragheh-Bonab plain , Cropping pattern , Non-dominated sorting genetic algorithm , Compromise programming method

Amir Molajou

Abbas Afshar