Technical Report NTB 84-49

FEM 301A Three Dimensional Model for Groundwater Flow Simulation

The purpose of this report is to describe program FEM 301. Program FEM 301 is a three-dimensional, finite element numerical model which solves the steady-state groundwater flow equation. Following a brief description of the mathematical model upon which the numerical model is based, the finite element approximation to the flow equation is presented. The solution method employed by FEM 301 is the frontal elimination technique of IRONS (1970).

The general structure of program FEM 301 is described as are the required input files and the generated output file. The listing of FEM 301 is included as Annex A3. As numerous pre­ and post-processing routines have been developed specifically for use with FEM 301 they are also presented.

Several sample problems and verification tests depict the application of FEM 301 to typical hydrogeologic problems. The principal application of FEM 301 has been, however, to evaluate the deep crystalline groundwater flow regime in central northern Switzerland. This application is described in a companion report NTB 84-50 (Kimmeier et al., 1985).