BOSS International

FEFLOW Features

FEFLOW (Finite Element Flow) is one of the most sophisticated groundwater modeling packages available. The program provides an advanced 2d and 3D graphically based modeling environment for performing complex groundwater flow, contaminant transport, and heat transport modeling.

Unparalleled Modeling Capability

FEFLOW is a finite element based model with a wide selection of numerical solvers for performing complex 2D and 3D steady-state or transient groundwater flow and contaminant transport modeling. FEFLOW’s finite element approach allows the user to quickly build a model to accurately analyze groundwater flow and transport for complex 3D geology. FEFLOW simulation capabilities include:

  • Fully transient, semi-transient, and steady-state groundwater flow and contaminant transport for saturated and/or unsaturated conditions (2D & 3D).
  • Particle tracking and flow pathlines.
  • Confined and unconfined aquifers, including multiple free surfaces (e.g., perched water tables).
  • Chemical mass transport (e.g., linear/nonlinear sorption, decay, convection, dispersion).
  • Fluid and solid heat transport (e.g., storage, convection, thermo-dispersion, heat-transfer).
  • Density-dependent flow (e.g., saltwater intrusion, buoyant heat transport, thermohaline systems) and dependency on fluid density.
  • Time-varying, constrained boundary conditions.
  • Time-varying material data

FEFLOW's finite element based model allows the user to quickly build a model to accurately analyze groundwater flow and contaminant transport for complex 3D geology. In this cut-away view, the computed contaminant plume analysis results are displayed for some recently discovered buried storage tanks at an abandoned chemical facility.

FEFLOW uses a Galerkin-based finite element numerical analysis approach with a selection of different numerical solvers and tools for controlling and optimizing the solution process. These include:

  • Fast iterative equation solvers appropriate for large systems, such as the PCG, BiCGSTAB, CGS, Restarted GMRES, and Restarted ORTHOMIN methods with preconditioning, as well as direct equation solvers.
  • Upwind techniques (e.g., streamline upwinding, shock capturing, etc.) are provided to minimize numerical dispersion.
  • Newton and Picard iterative techniques for non-linear problems and adaptive time-stepping.
  • Contaminant transport processes include advection, hydrodynamic dispersion, linear and non-linear sorption isotherms, and first-order chemical non-equilibrium.
  • Different parameter models (e.g., Van Genuchten, Brooks-Corey, etc.) and several forms of Richard’s equation implemented for unsaturated flow and transport problems.
  • Primary variable switching technique for an efficient simulation of unsaturated flows.
  • Vertical moving meshes for unconfined problems.
  • Automated adaptive mesh refinements can be used to optimize the numerical solution in regions with steep gradients.
  • Real-time graphs of transient heads, concentrations, temperatures, and fluxes at multiple points throughout the model domain are displayed during the solution process.
  • Open programming interface for linking external analysis programs and modules to FEFLOW.

FEFLOW provides powerful 3D graphical visualization of groundwater modeling results. In this figure, 3D pathlines are displayed for this multi-aquifer model showing the capture zone for the selected well head.

FEFLOW includes several 2D and 3D geostatistical interpolation methods (e.g., IDW, Akima, Kriging, etc.) for transforming measured field data (e.g., hydraulic conductivity, porosity, etc.) as input data for the model. In addition, FEFLOW also provides tools for calculating and graphically displaying flow volumes, mass, and heat fluxes (either steady-state or transient) across boundary sections, along a user-specified line, and within model subregions. Other tools include:

  • Particle tracking analysis (both 2D and 3D).
  • Budget analyzer for flow, mass, and heat balances.
  • Fluid flux analyzer for computing fluxes through cross-sections and layers.
  • Data calculator for performing data operations (e.g., difference maps, standard deviation, cumulative changes, symmetric plane reflection, comparison with observation wells, etc.)
  • Computation of the relevant area of influence.

FEFLOW's output capabilities are unparalleled, providing powerful 3D graphical visualization of the groundwater model. Here is a 3D rotated view showing the computed chemical mass transport pathlines of a contaminant for both the unsaturated and saturated zones.

Easy Model Development

FEFLOW finite element groundwater models can be quickly developed using a variety of means. For example, groundwater data can be read-in directly from an ArcInfo, ArcView, or MapInfo GIS, or can be interactively created using a mouse by simply pointing and clicking. Scanned TIFF aerial maps, ortho photos, and/or DXF maps of streets, parcels, and buildings can be displayed as a background image, allowing the user to quickly digitize the region to be modeled. A finite element mesh can then be created, with layers representing the different stratigraphic layers. Simple or complex geological formations can be easily represented using the finite element mesh. The model can then be interactively rotated and zoomed in 3D, allowing the user to easily review the model and interactively refine and optimize the mesh to achieve a design that is customized to the site being modeled. Boundary conditions and initial conditions are easily assigned by selecting nodes or elements faces. Features such as wells, constant head, and no-flow boundaries are easily defined. Transient data (such as recharge or well pumping), which is typically available in hydrograph form, can be read-in and edited graphically. This data can be interactively assigned to a single element or a series of elements.

Typical Applications of FEFLOW

FEFLOW's powerful analysis capabilities make it better suited for difficult and challenging 3D groundwater flow and contaminant transport modeling problems than other less sophisticated models like MODFLOW, MODPATH, and MT3D. Typical applications where FEFLOW can be applied include:

  • Groundwater Modeling
    FEFLOW can determine the spatial and temporal distribution of groundwater heads and contaminants for simple or complex geology.
  • Complex Contaminant Transport
    FEFLOW can analyze contaminant transport associated with waste disposal and storage sites for both the saturated and unsaturated zones.
  • Groundwater Remediation
    FEFLOW can quickly evaluate different groundwater remediation alternatives, assist in planning remediation strategies, and can optimize groundwater remediation system designs.
  • Aquifer Recharge
    FEFLOW can predict rates of infiltration and aquifer recharge due to precipitation, stormwater retention ponds, and artificial aquifer recharge.
  • Well Head Protection
    FEFLOW can be used in the design and evaluation of different well head protection alternatives.
  • Saltwater Intrusion
    FEFLOW can evaluate the impact of seawater intrusion due to groundwater pumping and/or mine dewatering activities along coastal regions.
  • Nuclear Waste Disposal
    FEFLOW can simulate the combined effects of geothermal gradients and saline groundwater flow for deep well injection of nuclear wastes.
  • Mine Dewatering
    FEFLOW can assist in the design and optimization of pumping well locations and pumping rates, and can determine the influence of dewatering activities on local and regional groundwater supplies.
  • Dam Seepage
    FEFLOW can analyze the moisture dynamics and seepage through a dam for both the saturated and unsaturated zones.

FEFLOW can generate cross-sections and fence diagrams for any model, and the resulting 3D view can be copied to the clipboard for pasting into other Microsoft Windows applications for report generation and presentation. The generated cross-sections in this figure illustrate saltwater intrusion into a freshwater aquifer.

Complete GIS Support

FEFLOW provides integrated GIS functionality (attribute handling, overlay and join functions) for spatial information and automatic parameter assignment. FEFLOW can share groundwater data with any ArcInfo, ArcView, or MapInfo GIS database, allowing the program to become integrated into regional groundwater management and environmental impact assessment tasks.

FEFLOW fully integrates with ArcView and ArcInfo GIS, allowing groundwater modeling data to be seamlessly shared with a GIS database. In this figure, the computed well head capture zone results have been exported to ArcView, showing the zone of influence relative to a neighboring contaminant site and a sewage treatment plant.

A GIS database is an ideal platform for generating, housekeeping, updating, storing, and displaying both measured data and computed results. FEFLOW can intelligently link to any GIS database structure, using attribute mapping of nodes, arcs, and polygons to represent geographical, hydrogeologic, physical, and computational data. For example, well pumping data is typically frequently updated, and FEFLOW can import this revised data from the GIS to update the numerical model. Then, after re-running the simulation, FEFLOW can then export the computational analysis results, such as a contaminant plume contour plot, back to the GIS. The GIS can then be used as a tool for technical planners and decision makers in long term groundwater and environmental planning and assessment. Arbitrary model cut-aways, cross-sections, fence diagrams, iso-surface plume plots, contour plots, and 3D rendering are provided. Here is a cut-away view of a complex aquifer system, displaying a particular parameter's distribution throughout the model.

Advanced Output Capabilities

FEFLOW’s model output capabilities are unparalleled, providing powerful 3D graphical visualization of the groundwater model. Arbitrary model cut-aways, cross-sections, fence diagrams, iso-surface plume plots, contour plots, flow vector plots, particle tracking plots, pathline plots, and 3D rendering are provided. Both FEFLOW’s computational analysis output and graphical output can be exported to GIS, CAD, ASCII text files, and copied to the clipboard for pasting into other Microsoft Windows applications for report generation and presentation. FEFLOW can display an animation of the analysis results, such as this transient contaminant transport simulation. In this figure we see the effect of a deep pumping well near two neighboring contaminant sites.