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Comparison of experimental and simulated infiltration profiles in sand

Abstract:

The validities of different K(θ) relations obtained from five experimental techniques and three numerical methods were evaluated using experimental data of vertical infiltration for the same soil. The different K(θ) relations were used in a simulation model of vertical infiltration assuming a constant rate of water application lower than the saturated hydraulic conductivity. The simulated data of moisture contents and depths of wetting fronts were compared with the experimental measurements. Among the experimental methods for the K(θ) relation, the instantaneous profile method (IPM) resulted in the best description of the infiltration profile for the sand used in this study. Among the numerical methods of K(θ) estimation, Irmay’s model compared favorably with Jackson’s (p = 1) and Mualem’s (x = 0.5) approaches. The prediction of the Jackson model could be improved by setting p equal to 0.5 instead of 1. We conclude that numerical methods of estimating the K(θ) function can be substituted for the experimental methods only if great care is taken in choosing the proper physical parameters for the soil under consideration. © 1982 The Williams & Wilkins Co.