A Comparison of Numerical Simulation Models For One‐Dimensional Infiltration

TLDR

The study compared six infiltration models differing in discretization to evaluate execution time, accuracy, and programming considerations. The models employed various discretization approaches for the nonlinear infiltration equation. All models agreed well with measured water‑content profiles; implicit schemes, including those using the Kirchhoff transformation, were faster and more broadly applicable than explicit models, and the implicit finite‑difference model matched Philip’s quasi‑analytical solution for water distribution, infiltration rates, and cumulative infiltration.

Abstract

Abstract Six models, employing different ways of discretization of the nonlinear infiltration equation were compared in terms of execution time, accuracy, and programming considerations. All models yielded excellent agreement with water content profiles measured at various times in a sand column. The two explicit models, the θ‐based CSMP model and the h ‐based explicit model, used between 5 and 10 times more computer time than the implicit models. Results obtained with the two models which used the Kirchhoff integral transformation were no better than those obtained with the two h ‐based implicit models. The implicit schemes with implicit, or explicit evaluation of the hydraulic conductivity and water capacity functions appear to have the widest range of applicability for predicting water movement in soil with both saturated and nonsaturated regions. Excellent agreement was obtained between water content distributions, infiltration rates, and cumulative infiltration volumes calculated with the implicit finite difference model and Philip's quasi‐analytical solution.