Determination of Wetting Front Suction in the Green‐Ampt Equation

Abstract Interest in the Green‐Ampt equation to predict infiltration rates into uniform and layered soils has increased in recent years. The work reported here is a study of the theoretical justification of determining the suction (at the wetting front) parameter in the equation from the hydraulic conductivity versus capillary suction relationship for the soil. It is shown that the wetting front suction so determined and used in a form of the Green‐Ampt equation which allows for the surface boundary condition initially being one of constant flux gives predictions of infiltration volumes comparable to those determined by numerical solution of the complex partial‐differential equation of moisture flow.