An Approximate Analytical Solution of Richards' Equation

An approximate analytical solution of Richards' equation (RE) in a semi-finite layer of porous medium is obtained in this article. The basic idea is constructing a function between the Boltzmann variable phi and the traveling wave solution of RE, introducing the function into RE and calculating the relevant parameters by differential transform method (DTM). In the end, three examples are prepared to show the accuracy of the presented approximate analytical solution.