1.   Purpose and objectives

     MicroFEM is a Windows program to create and analyse a wide range of multiple-aquifer steady-state and transient groundwater flow problems using the finite-element technique.

2.   Description

     Confined, semi-confined, phreatic, stratified and leaky multiple aquifer systems can be simulated with a maximum of 20 aquifers. The maximum number of nodes per layer is 50.000 (100.000 triangular elements). MicroFEM supports heterogeneous anisotropic aquifers and heterogeneous aquitards. 
The program handles multiple time-varying sources and sinks, as well as spatially and temporally varying boundary conditions. It uses various modes for the generation of a mesh, model setup, input preparation and editing, equation solving, postprocessing, graphical interpretation and plotting.

     Data manipulation and grid design and editing is supported by a highly interactive graphic interface, with multiple user-assigned names for all nodes. Two sophisticated grid generators are included: FemGrid for irregular boundaries and FemMesh for complex grids requiring high contrasts in node-spacing between different parts of the model. Top system boundaries can be selected for any area as a combination of precipitation, evaporation, drains, rivers and wadi conditions.

3.   Input

     Data may be loaded manually, via the screen or from ASCII files created by GIS programs.

4.   Output

     Post-processing includes the display of transient (animated) contour lines, velocity vectors, flowlines in two or three dimensions (particle tracker), steady-state and transient water balances for any region, head- profiles, cross-sections, and time series of heads and fluxes. MicroFEM supports import and export functions for ASCII model files, SURFER, EXCEL and ARCView compatible data files, DXF maps and flowlines, HPG-plot files and screen resolution output to printers.

5.   Operational requirements and restrictions

     MicroFEM is written in Delphi and requires a PC with Windows operating system.

6.   Form of presentation

     The zipped MicroFEM code only takes 1 MB (it fits on a single 3.5" floppy disk), including the detailed description that can be found in the on-line help system.

7.   Operational experience

     Over 500 copies are in use at 240 sites in 15 countries.

8.   Originator and technical support

     C.J.Hemker, Faculty of Earth Sciences, Vrije Universiteit Amsterdam. Technical support by e-mail: hemker@microfem.nl

9.   Availability

     From the HOMS National Reference Centre for the Netherlands. A reduced light-version with two aquifers and 2500 nodes per layer is available from the MicroFEM web site, as well as documentation, a tutorial, example models and utilities to exchange data files with ArcView, ModFlow and Excel. Web 
Page URL: http://www.microfem.com.

10.  Conditions on use

     The reduced version and MicroFEM utilities are available on the Internet free of charge. The full version of MicroFEM is subject to a  Licence Agreement at commercial rates. Discounts are available for  educational use.