Infiltration Into Increasingly Permeable Soils

A tabular procedure, based on the Green-Ampt equation, is developed to calculate infiltration into soil that becomes more permeable with depth. The procedure is simple and the results compare favorably with those obtained with a digital computer. The procedure supplements a previous paper which showed how the Green-Ampt equation can be used to calculate infiltration into soil becoming less permeable with depth. The Green-Ampt equation is emerging as a useful, simple, and yet theoretically sound infiltration equation. The extension of the equation to soils where the permeability changes with depth should enhance its utility in practical applications, where soils are seldom, if ever, uniform.