مقايسه مدل هيدرولوژيكي ماسكينگام-كونژ با مدل هاي هيدروليكي آبياري در برآورد مرحله پيشروي آبياري جويچه اي

Comparison of Muskingum - Cunge model with irrigation hydraulic models in estimation of furrow irrigation advance phase

Prediction and calculation of advance and recession curves in furrows require a series of accurate field measurements which is both time consuming and expensive. The basic aim of this research is application of a flood routing method in simulation of advance rate in furrow irrigation and comparing it with results of SIRMOD models. Muskingum - Cunge model was performed with 27 series of field data and compared with SIRMOD results. Field experiments were performed in Shahid Chamran University field area, in Ahwaz, Iran. The tests were conducted in three furrows with length of 60, 80 and 90 meters, three discharges of 1, 1.25 and 1.5 liters per second and with three replications. For evaluation of the results, four indices: average prediction error of model (Er), distribution into 45° line regression coefficient (R2) and average relative error of model (Ea) were used. According to the results, estimated values of advance phase in all models were more than observed values. Hydrodynamic and Zero Inertia models owned the best results with 11.19 percent average relative error. Average relative error by the Muskingum - Cunge was 13.47 percent. This object showed that the Muskingum - Cunge model is a suitable model for predicting of advance phase in furrow. Kinematic wave model gained the weakest results with 34.46 percent of average relative error. Results indicated that with a smaller furrow length and the higher inlet discharge, predictability of the Muskingum - Cunge model will be better. Finally, the results showed that the Muskingum - Cunge model is simple and found to effectively simulate the hydraulics of the advance phase of furrow irrigation.