Calculation of non-steady flow towards a drain in saturated-unsaturated soil by finite elements

The problem of two-dimensional non-steady flow of water towards a drain in saturated—unsaturated soil is solved by a Galerkin-type finite element approach. Special emphasis is placed upon the type of boundary conditions to be used at the circumference of the drain, the hydraulic conductivity of the soil and the discretization scheme of the finite element network. Numerical solutions are compared with the Thiem—Dupuit well formula and with hodograph solutions given by Van Deemter (1950) and Childs (1959).