Optimal Model of Irrigation Network Operational Management to Maximize Profit (Case Study: Ghazvin Irrigation Network)

Considering the limitation of water resources and their value in agriculture, determining the optimal crop cultivation pattern and irrigation planning in low water conditions in the country's catchments is of great importance. Therefore, it is necessary to develop an optimal cultivation model to be flexible in wet and dry conditions. The purpose of this study is to develop a model for offering the best program for irrigation and cultivation area for network operation under different conditions of water resources. After receiving basic information (plant, soil and meteorology) and various irrigation and deficit irrigation scenarios by connecting to the plant growth model (Aqucrop), the model calculates crop yield under defined scenarios. The scenario with the highest economic efficiency is determined as irrigation planning and by connecting to Ant Colony Optimization (ACO), the optimal cultivation pattern for different volumes of available surface water is determined with the aim of maximizing net profit. The optimal cultivation pattern for all crops grown in Qazvin irrigation network in four different modes of water delivery (100%, 80%, 75% and 70%) was performed for 93-94 crop year to evaluate the efficiency of model. The results showed when the year is normal and the amount of water delivered to the network is equal to the long-term average (100% scenario), the largest area is allocated to wheat cultivation (10740) and the dryland will be the least. In the case of 70% of average annual long-term amount to be provided, the area under wheat cultivation will be 3,000 hectares, and about 15,000 hectares of the network must be managed dryland or without irrigated cultivation. The results showed that the developed program with high capability and high flexibility for a variety of existing conditions is able to determine the optimal pattern and maximize network profits.