1-DIMENSIONAL, 2-DIMENSIONAL AND 3-DIMENSIONAL MODELING OF WATER-MOVEMENT IN THE UNSATURATED SOIL MATRIX USING A FUZZY APPROACH

Modeling water movement in the unsaturated soil matrix is usually base d on the numerical solution of the Richards equation. This approach re quires much computational effort, therefore practical 2- or 3-dimensio nal applications are extremely rare. The purpose of this paper is to d escribe a computationally efficient and simple method. It is based on a transformation of the unsaturated Darcy law to a fuzzy rule system. The rule system is combined with the continuity equation yielding a fu zzy rule-based model for simulating the unsaturated flow. Basic defini tions of fuzzy logic are given and the concept of the unsaturated how model is outlined. The presented model performs well compared with a s emi-analytical model and a 2-dimensional, numerical model. Furthermore the model has been incorporated into a physically-based and distribut ed, hydrological model. Model simulations for different types of hydro logical situations show that the fuzzy rule-based approach is especial ly suitable for real-life applications.