الهام سليمانيان

In recent years, the water, food and energy nexus has received much attention. In this study, in order to model the inetractions between water, food and energy, first the nexus modeling approaches were examined and the disadvantages of each of them were identified. Based on this, nexus modeling approaches can be divided into two groups: 1- Integrated modeling and 2- Compiled modeling. The integrated modeling approach uses one framework to model the nexus system, while the integrated approaches use separate models to simulate each of the nexus subsystems, and finally integrate their results. According to a review of research, neither of the two approaches mentioned is capable of considering the interrealations of each subsystem and the interactions between subsystems at each time step. Therefore, it is necessary to develop a comprehensive nexus simulator model that can examine interrelations and interactions at any time step. In this dissertation, a water simulator model that is able to simulate important interrelations which can affect the interactions of the nexus system is specifically developed using the Python programming language. The water simulator model for nexus is able to run in two modes of stabd-alone and linked mode with two other subsystems. In the stand-alone mode, the interactions with the two food and energy subsystems are entered into the model in time series, and in the linked mode, the model has reciprocal interactions with the other two subsystems in each time step. By simulating the important interrelations of the water subsystem, the quantitative and qualitative values of the water subsystem are better determined, and as a result, the interactions of the water subsystem with the two food and energy subsystems are determined more precisely. Examining the extent of interactions between subsystems helps to better manage each of subsystem and ultimately create sustainablity in each of the subsystems. The developed water simulator model has evaporation simulation modules, surface flow and groundwater flow, reservoir operation, surface water and groundwater exchange, and salinity simulation. The performance of each module was eva‎luated during the calibration period for the calibration years 83-89 and then in validation years 89-92. The values of model eva‎luation indicators during the calibration and validation period were eva‎luated as satisfactory and acceptable for all all modules. Considering the values of performance indicators, it can be acknowledged that the developed model has a good performance in simulating the water subsystem. For example, the Nash index value for the evaporation module is 0.92 and 0.92, for the flow routing module is 0.54 and 0.51, for the first zone groundwater is 0.60 and 0.71, the second zone groundwater is 0.68 and 0.48, the third zone groundwater Equal to 0.69 and 0.64, for groundwater of the fourth region equal to 0.92 and 0.64 and for simulation of salinity in the river equal to 0.53 and 0.48 during the calibration and validation periods, respectively. The good accuracy of the developed water model, considering that it is possible to study the interactions with two food and energy subsystems, is considered as an important finding of this research and an important step in obtaining a suitable tool for simulating the water, food and energy correlation system.

Elham Soleimanian

Abbas Afshar