Horizontal Infiltration Method for Determining Brooks‐Corey Model Parameters

Abstract

Mathematical models have been widely used to predict water and solute transfer in soil and ground water. The accuracy of water flow and solute transport predictions obtained with these models depends to a large extent on the reliability and accuracy of the soil hydraulic properties. The main soil hydraulic properties are the water retention curve and hydraulic conductivity function. Most methods for determination of soil hydraulic properties that include flow measurements require elaborate instrumentation and a substantial amount of time. It is important to develop simple flow‐based experimental methods to estimate soil hydraulic properties. In this paper, an analytical method was developed to determine Brooks‐Corey model parameters. The problem of water absorption into a horizontal soil column was solved, and the relationships of cumulative infiltration, infiltration rate, and infiltration time with distance to the wetting front were obtained. Based upon these relationships, a method to estimate soil hydraulic properties was developed. Numerical simulations of water flow into horizontal soil columns were used to evaluate the analytical method. The analytical model was fitted to the numerical infiltration results with coefficients of determination ranging from 0.97 to 0.99. The results based upon the numerical data indicate that the estimated hydraulic properties agreed closely with the given values. The analytical method provides a simple and quick transient water flow approach to estimate soil hydraulic properties.