معرفی یک مدل ریاضی جدید برای ارزیابی و بهینه سازی عملکرد کانال‌های آبیاری

Poor performance of irrigation canals and its effect on decreasing of Agricultural water productivity require attention for their improvement. In this paper a new mathematical model is introduced which could present optimal operation considering downstream requirements of turnouts, canal inlet flow, actual constraints and real conditions of canal system. Four performance indicators of delivery including efficiency, adequacy, equity and stability are considered as an objective function in the process of optimization. Since this objective function is an implicit function of decision variables (regulation of turnouts and control structures) and hydraulic parameters, it is necessary to implement hydrodynamic model, using numerical optimization methods. SA (Simulated Annealing) technique is a numerical meta – heuristic intelligent search method which is used in combination with a hydrodynamic model (ICSS) (Irrigation Conveyance System Simulation.) for performance optimization of canal system. Theoretically it is proven that SA technique is capable of tending towards global optimum solution asymtotically. Taking short random steps in SA algorithm guarantees avoiding instability in hydrodynamic model. The developed model has been applied on E1R1 Distributary canal of Dez irrigation network for ten days. The results indicated that optimal performance improved very well in comparison with the present situation.In this model the weighting coefficients of indicators are determined using sensitivity analysis in optimization process. Consistency test on the derived coefficients shows that proposed method is appropriate. Applying weighting coefficients for performance indicators in the processes of optimization has resulted in 7 to 21 percent improvement compared to the case of equall weighting coefficients. Also, the results indicate that the developed model (ICSS-DOM) (ICSS-Delivery Optimization Model) is an efficient tool for the evaluation and optimization of irrigation canal performance, producing good and valid results in a relatively short and suitable time.