Quantitative descriptions of the two-phase flow in the subsurface soil require knowledge of the relative permeability-saturation-capillary pressure Kr-S-Pc relationships. The significance of the present study lies in introducing a physical model that was used to measure the capillary pressure-saturation curve for the twophase kerosene-water system in Kerbala’s sand. The experimental results are fitted with the empirical mathematical function described by (Parker et al., 1987) which is based on (Van Genuchten’s model, 1980). This function can be used to specify the residual water saturation, Sr, and Van Genuchten’s soil parameters, α and n. The best-fit curve was found by using a nonlinear least squares fitting routine using the SPSS software version 7.5. The fitting parameters Sr, α and n for the best-fit to Van Genuchten’s capillary pressuresaturation curve for kerosene-water system have the values of 7%, 0.048 cm-1 and 2.7, respectively, for Kerbala’s sand
