Effect of Surface Boundary Condition on Rainfall Infiltration

Rainfall infiltration is greatly influenced by the surface boundary condition as well as hydraulic properties of soil. This paper highlights the study on the effect of several surface boundary conditions on the rainfall infiltration using a computer program VADOSE/W. A parametric study was carried out to study the effect of ambient temperature, relative humidity and wind speed on the evaporation and rainfall infiltration rate. The effect of soil hydraulic conductivity on the mechanism of rainfall infiltration was also studied by using two soil column models. Results show that rainfall infiltration is sensitive to relative humidity and ambient temperatures lower than soil temperature, but insensitive to wind speed and ambient temperatures higher than soil temperature. The hydraulic conductivity of soil and rainfall intensity have great influence on the infiltration mechanism and the development of surface runoff. Thus, reliable saturation profile can only be achieved if accurate surface boundary condition was considered for analysis