The effects and interactive effects on infiltration of parameters in the Brooks-Corey equation for defining the hydraulic properties of unsaturated soils are investigated by analyzing the results of numerical solutions of the unsaturated flow characteristics resulting from water applied on a circular surface area. The soil parameters are allowed to vary continuously as a function of depth. The parameters that have been allowed to vary separately and in pairs are: (1) The pore size distribution exponent, (2) Pb- The bubbling pressure, (3) Sr- The residual saturation, (4) n- The soil porosity and (5) Ko- The saturated hydraulic conductivity. The conclusions are: (1) heterogeneity of the soil defined by allowing any parameter to vary with depth has a significant effect on all infiltration characteristics, (2) there is a minor to insignificant interaction between the soil parameters, and (3) the additive law of effect can be used to determine the composite effect of several soil parameters varying simultaneously.
Nassehzadeh-Tabrizi, Abdolhossien and Jeppson, Roland W., "Influence of Unsaturated Hydraulic Properties on Infiltration from Circular Surface Areas" (1980). Reports. Paper 178.