Vertical infiltration of water into unsaturated soils with variable diffusivity and conductivity

Abstract

A simple approximate analytical solution to the problem of vertical infiltration of water into unsaturated soils is presented. The soil-water diffusivity as well as the hydraulic conductivity are assumed to be exponential functions of the soil-water content. Constant-concentration conditions are assumed at the boundary. The infinite-domain problem is reduced to a finite-domain problem under the assumption of an abruptly terminating wetting front coinciding with the inflection point of the soil-water content profile. The location as well as the soil-water content at the inflection point are calculated and the result is employed for the approximate solution of the problem. Results are compared with others found in the existing literature. A discussion concludes the paper.