TR-104 : Development of a soil moisture prediction model

Abstract

Flow of water through unsaturated porous media is common in nature. The basic equation of flow in the unsaturated zone of a porous medium is Richards' equation. The exact solution to the Richards' equation is not yet known. Therefore finite difference methods are widely used for solving the partial differential equation describing one-dimensional water transfer in unsaturated soil. The purpose of this study was to develop a numerical model of transient, one-dimensional water, flow through the unsaturated porous medium. Seven models, employing different ways of discretization of the nonlinear infiltration equation, were compared with Philip's quasi-analytical solution. All models yielded good agreement with water content profiles at various times in a sand column.