New Approximate Analytical Technique to Solve Richards Equation for Arbitrary Surface Boundary Conditions

A general approximation for the solution to the one‐dimensional Richards equation is presented. It applies to arbitrary soil properties and boundary conditions but only uniform initial conditions at current stage. The result is very accurate (within 2%) when the diffusivity is constant, suggesting that the present general formulation is reliable, since the approximation becomes increasingly accurate as the soil‐water diffusivity approaches a delta function.Griffith Sciences, Griffith School of EnvironmentFull Tex