An Approximate Explicit Green–Ampt Infiltration Model for Cumulative Infiltration

Abstract

Core Ideas Proposed an explicit Green–Ampt model (EGA model) to estimate cumulative 1D vertical infiltration. The form of error term ε is determined as a power‐function through non‐dimensional numerical analysis. The EGA model is reliable for estimation the cumulative infiltration for a variety of soil textures. Accurately estimating soil moisture infiltration information contributes to scientific understanding of the one‐dimensional (1D) vertical infiltration process. Because of its simple form, the Green–Ampt (GA) model has been extensively employed to simulate soil infiltration processes. However, the GA model is an implicit solution that must be solved through iterative techniques, and thus is inconvenient. Therefore, based on the two‐parameter infiltration equation proposed by Valiantzas, by adding an error term and non‐dimensional numerical analysis, this study proposes an approximate explicit Green–Ampt model (EGA model) for estimating cumulative infiltration with a determined power function expression for the error term. A total of 12 typical soils were selected from the USDA soil textural classes, and the 1D vertical soil infiltration process was simulated using Hydrus‐1D. The reliability of the proposed EGA model was verified using measured and simulated values. The mean absolute percentage relative error (MAPRE) and percentage of bias (PB) were taken as evaluation indicators to compare the estimated cumulative infiltration with the measured and simulated values. The results revealed that all cumulative infiltration values estimated by the EGA model are in good agreement with those measured in laboratory experiments and simulated using Hydrus‐1D; the mean MAPRE and PB values of all treatments were 4.2 and 0.7%, respectively. In addition, the estimated errors of the EGA model were consistent with those of the GA model. Hence, the EGA model can estimate the cumulative infiltration in 1D vertical soil infiltration with high accuracy and is suitable for a variety of soil textures.