Simulation of Border Irrigation Using the two Numerical Schemes

Saint-venant equations constitute some of the basic relations that play important roles in different hydraulic studies، including the ones in surface irrigation. Throughout the present study، full hydrodynamic model of the flow was solved using finite difference method and dispersive explicit Lax (HD-LAX) as well as MacCormack (HD-MAC) schemes. In order to evaluate these two schemes، output with six measured data series were compared under different conditions. The results revealed that within an irrigation border، the prediction accuracy in both schemes increased by increase in inflow. The simulation accuracy of both schemes decreased by increase in length، width and slope of the border. The findings indicate that HD-LAX scheme with respective 0. 9452 and 0. 8366 coefficients of determination within the advance and recession flow phases’ simulation، and with -5. 63 and 7. 87 percent of the relative error are of more accuracy (in infiltrated water volume and runoff estimation) as compared with HD-MAC scheme.