Simulation of Soil Moisture Profiles Using K(h) from Coupling Experimental Retention Curves and One-Step Outflow Data

Abstract

In the present work, the effect on the soil moisture profiles development and the cumulative infiltration when three different equations for calculating the diffusivity versus volumetric water content, D(θ) function, from one-step outflow experimental data are used, is investigated. These D(θ) functions are coupled with moisture retention curves θ(h) (h being the soil matric potential) obtained independently for the determination of the hydraulic conductivity function K(θ) or K(h). The so obtained hydraulic conductivity function, together with θ(h), were employed in solving Richards equation numerically under constant flux conditions in one dimensional vertical infiltration process. Two different porous materials were used for this investigation. It is shown that the three different equations used for the prediction of K(h) have no significant effect on the shape of the moisture profiles for the sand mixture and that a Green–Ampt advancement of the wetting front is observed. For the case of sandy clay soil there are some noticeable differences in the moisture profiles and their shape is comparatively more effusive. Also, one could mention that for both porous media the time of incipient ponding (T) differentiates among the three equations used.