Investigation and Analysis of flow and Geometric Variables on Optimal Performance of Border Irrigation using WinSRFR model

The low irrigation application efficiency is the major problem of surface irrigation systems due to weak management and poor design. The purpose of this study was improvement of border irrigation performance based on four variables including inflow rate, cut off time, slope and border length. For this purpose 8 series of the field experimental borders were considered with open-end downstream condition. Calibration of infiltration parameters of borders were conducted based on multilevel optimization method. The results indicated that the multilevel optimization method for prediction of infiltration parameters in border irrigation was an acceptable method. According the multilevel optimization method, the mean relative error for the volume of run-off prediction was determined to be 0.5% and the average of root mean square error for advance and recession times predicting about 3.1 and 3.2 minutes, respectively. The performance of borders was optimized using application efficiency and distribution uniformity performance contours of the WinSRFR. Based on flow variables (inflow rate and cut off time), the average of application efficiency could be increase about 12 % (with adequacy equal to 100%) for 8 series of the field experiments compared with current evaluation. Results indicated with considering geometric variables (slope and border length) more over the flow variables as decision variables, affected on optimal irrigation performance partially and in terms of all flow and geometric variables, the average of application efficiency could be increased about 13.35 % compared with current evaluation.