Peter W. Kleeman

AN INFILTRATION MODEL TO PREDICT SUCTION CHANGES IN THE SOIL PROFILE

A computer model for the infiltration at the soil surface is described. The model has been developed for computation of seasonal suction changes in the soil profile. It simulates time dependence of the vector of sources and sinks for the finite element solution of Richards equation. Lumped meteorological and soil parameters are used. Meteorological input to the model consists of the records for rainfall, pan evaporation, air temperature, and air humidity. As an example of an application of the model, the daily magnitudes of infiltration/evapotranspiration at the soil surface at Maryville, New South Wales, Australia, in March and April 1993 were obtained, and the resulting suction profile was calculated numerically. This example shows that the model adequately reflects major meteorological changes. The resulting suction profile correlates well with the experimental data, better than profiles resulting from the models, which assume periodic or sudden changes in surface suction.