Development of Management Schemes in Irrigation Planning: Economic and Crop Pattern Consideration

Increasing population has dramatically increased the request for agricultural products. In addition, lands and water resources with suitable quality are limited. Therefore, optimal allocation of limited resources to di erent demands has become very important in recent years. In this study, a model is developed to optimize a water resources allocation scheme considering the conjunctive use of surface water and groundwater resources, as well as determining a suitable crop pattern. The economic objective function of the optimization model is to maximize the net bene t, considering the water pumping cost, crop cultivation cost and the bene t of total crop production during the study time horizon. The e ect of a marginal water de cit in the reduction of crop yield and water table uctuations are considered. A genetic algorithm is used to solve the optimization model. The proposed model is applied to the Varamin plain to determine the optimal crop mix and water allocation from surface and groundwater. In order to evaluate the results of the model, the performance indices are calculated. The e ect of imposed policies on the crop pattern is investigated through the de nition of two scenarios and the results are compared. Also, the potential of the study area, for applying de cit irrigation strategies using economic analysis, is investigated.