Simulation of the Flow and Solute Transport in Three Farms With Different Lateral Distances in Gamboa Irrigation and Drainage Network With HYDRUS 2

Based on this topic, the present study was conducted in order to evaluate the HYDRUS model in estimating the salinity and water table level of three farms in Gamboa irrigation and drainage network. This area is located in the agricultural lands of Hamidieh city.experiments were conducted in 2023 during three stages of irrigation in wheat farms, with area about 8 ha, in three fields with three lateral spacing 50, 75 and 80m. The results showed that HYDRUS had an underestimation error (MBE<0) in the estimation of two parameters, water table level and drain salinity, but the calculation error of both parameters was acceptable. In addition, the accuracy of the HYDRUS in simulating the water table level in all three farms was in the excellent category (0.0<NRMSE<0.1). The changes in the lateral distance had no effect on the HYDRUS error or accuracy. Failure to consider soil salinity at the beginning of the simulation caused the small error of estimating drain salinity in the first three days in all three farms. But at the end of the simulation, the salinity calculation error in all three farms was less than 7%. Also, when approaching the drainage outlet, due to the failure to consider the role of the collector in the HYDRUS, its accuracy decreased slightly compared to the beginning of the farm. However, considering the results, we can trust the accuracy of HYDRUS model in estimating the water table level and soil salinity in sugarcane farms.