Optimal management pattern for water resources utilization, case ‎study: Alashtar Plain

Utilization of water resources، using a combination of simulation and optimization، are a useful and powerful set for specifying decision-making and management strategies. In this regard، MODFLOW mathematical model، as an efficient and cost-effective tool to evaluate different management options was used. After providing a conceptual model of the aquifer، requirement data were defined in different versions of the V. MODFLOW (V. 5. 33) software. Then، the model was calibrated by the manual method that has higher accuracy than software techniques and validation operations were also carried out. In the simulation process، with the goal of water resource management، the results of modeling and calibration model were used to optimize the groundwater table level. In this study، a linear programming model was used for optimizing the management. Lingo software was used to implement this model and achieve the optimal management. The information needed to solve the problem، was based on the output of a simulation model and optimization options. Due to linearity of objective function، a multi-objective linear programming model was selected to solve the problem. General multi-objective optimization problem with n decision variables، m constraints and p objectives is presented in optimizing relationships. The objectives of the optimization problem were maximizing the profits of agricultural products and minimizing the use of aquifer water. Results indicated that the amount of yield and water use were different before and after optimization.. The amount of annual water consumption before optimization was 92. 22 million m3 while after optimization was 75. 51 million m3. In other words، the rate of water consumption was reduced by 18 prevent. Results also showed that annual water consumption in agriculture was 31. 79 million m3 that shows 65. 5 percent reduction compared to the present situation. The amount of benefits before optimization was 47، 798 million Rials، while after optimization it was 63،689 million Rials. In other words، the amount of total profit increased by 33. 25 percent. Based on the scenario of a national document (pure water requirement)، total profits increased by 15 percent.