Approach for predicting the wetting front depth beneath a surface point source: Theory and numerical aspect

Using experimental data, the continuity and the cumulative infiltration equations, a new expression for predicting the wetted soil depth was described. Knowing soil hydraulic conductivity K(h(f)), initial and wetting front water content, this method enables us to calculate the maximum front depth Z(f)(t), beneath an emitter, by only measuring its radius R(f)(t) on the soil surface. To test this, we used the ADI finite difference method to solve Richards' equation for axisymmetrical water infiltration from a point source on the. soil surface. To simulate the evolution of the wetted soil volume dimensions (R(f)(t) and Z(f)(t)), proper conditions were fixed for the wetting front boundaries. The Z(f)(t) predicted values were compared with those computed and measured during an axisymmetric water infiltration test on a silty soil for three different discharge rates. The results obtained showed good agreement between predicted, computed and measured data. Copyright (C) 2002 John Wiley Sons, Ltd.