We developed a numerical method (ASG method) for simulating a coupled atmospheric gas-surface water system, simulated by Navier-Stokes equations, and groundwater system, simulated by water saturation equations. Here, we derived dimensionless formulas for ASG method to avoid the influence of a dimension of analytical domain, in this study. Further we used the ASG method to simulate the configuration and movement of the infiltration front in an embankment composed of sand and obtained results similar to those obtained by a water tank experiment in another study. In addition, in a practice problem using non-dimensional values, we simulated the movement of gas and water when surface water flowed over an embankment expressed in dimensionless form.Consequently the ASG method could simulate the movement of water and gas across the interface between a surface system and a porous medium including the practice embankment.