ABCFEM is a two-dimensional, numerical flow and transport model. The flow problem is solved using a modified Gauss-Seidel iterative finite element approach and the transport problem is solved using a Random Walk approach. The program can be used for the solution flow problems or it can be used to analyze flow and solute transport together in a single domain. Steady state or transient groundwater flow systems can be analyzed including pumping or injection wells. Boundary conditions handled by the program include fixed flow, fixed head, forced inflow, infiltration and swamping. For unconfined systems a moving phreatic surface can be simulated allowing for mixtures of confined and unconfined nodes (as long as confined nodes remain fully saturated). The ability for the phreatic surface to move creates the possibility for groundwater to emerge at the ground surface forming a spring or a stream. The head can also be constrained below ground surface. This makes it possible to model stream/ground water interactions and gaining or losing streams. ABCFEM can perform inclined plane analysis for horizontal systems, vertical section analyses based on head differences and radial analyses for systems whose flow and head behavior have radial symmetry.

ABCFEM has a finite element frid generator and a menu driven input preprocessor with extensive help files. Utilities for moving data in and out of the program into spread-sheet style files is provided. The program supports a variety of printers and plotters and can create output files compatible with contouring packages or DXF file format for further analyses.

ABCFEM is a proprietary program. The DOS-formatted distribution disks contain executable images and example data sets. The documentation consists of installation instructions, theory, input instructions, and example problems.

SYSTEM REQUIREMENTS

Intel 80386 based computer, math coprocessor, 640 Kb RAM (4 Mb recommended), VGA graphics, and DOS 3.1.

Developer: A. Brown and R. Hertzman (Adrian Brown Consultants Inc.)