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FESWMS Screenshot
Model Info
Model type Two-dimensional finite element surface water computer program that can compute the direction of flow and water surface elevation in a horizontal plane. Also has the ability to model hydraulic structures commonly used by hydraulic engineers.
Developer David C. Froehlich, Ph.D., P.E.
Web site FESWMS page

General Section

  • Mesh Editing
  • Observation
  • Overview
  • Sensitivity

Models Section

  • FESWMS Steering
  • FESWMS Weirs

The Finite Element Surface Water Modeling System (FESWMS) consists of multiple modules used to simulate surface-water flow in a two-dimensional horizontal plane. The SMS includes an interface for the FST2DH (Flow and Sediment Transport) module of FESWMS. FESWMS is sponsored by the Federal Highway Administration. David C. Froehlich, Ph.D., P.E. originally developed FESWMS for the United States Department of Transportation Federal Highway Administration (FHWA) and the United States Geological Survey (USGS). The FHWA has continued to maintain and sponsor development of subsequent versions, which continue to incorporate features specifically designed for modeling highway structures in complex hydraulic environments.

The FESWMS model can be added to a paid edition of SMS.


FST2DH is the FESWMS program that performs the two-dimensional hydraulic computations in surface-water bodies. FST2DH can perform either steady state or dynamic flow modeling and provides analysis of highway crossings and structures, including bridges, culverts, weirs, roadway embankments, and drop-inlet spillways. FST2DH simulates the movement of water and non-cohesive sediments in rivers, estuaries, and coastal waters by applying the finite element method to solve steady-state or time-dependent systems of equations that describe two-dimensional depth-averaged surface-water flow and sediment transport. [1]

Using the Model / Practical Notes

General Steps to build a FESWMS Model

Various sequences of steps can be used to create and edit a two-dimensional model in SMS. A suggested methodology is provided below.

  1. Import background data consisting of:
    1. Elevation data covering the area to be modeled. See Scatter Module
    2. Open and register background image(s) if desired. See Images
  2. Create a FESWMS coverage and define the conceptual model that will be used to generate the finite element mesh. See Map Module
    1. Define the physical boundaries of the model
    2. Build feature polygons within the model domain. See Build Polygons in the Feature Objects menu.
    3. Assign mesh types to the feature polygons and adjust the density and spacing of vertices (i.e., redistribute vertices) as necessary to achieve appropriate element shapes and sizes
  3. Creata an area properties coverage and assign material types. This is an optional step. The FEWSMS coverage can also be used to define material regions. See Map Module
  4. Generate a finite element mesh from the conceptual model. See Map Module
  5. Check the final quality of the finite element mesh and edit the mesh as needed. See 2D Mesh Module
    1. Designate element types (i.e., linear or quadratic; triangular or quadrilateral)
    2. Review the mesh quality
  6. Specify FESWMS element attributes (i.e., material properties) such as Manning's or Chezy roughness factors and eddy viscosity to the material types. See 2D Mesh Module
  7. Create nodestrings and assign model boundary conditions not included in the conceptual model. See 2D Mesh Module
  8. Renumber the finite element mesh.
  9. Specify initial conditions and model control parameters. See FESWMS Model Control
  10. Run the model.
  11. View model results. If necessary, troubleshoot error/warning messages generated during the model run and revise the model accordingly.

Graphical Interface

SMS provides a graphical interface that is designed to visualize the projects being created, easily modify project parameters, and view the solutions produced by the FESWMS model. See FESWMS Graphical Interface for more information.

The FESWMS graphical interface contains tools to create and edit an FESWMS simulation. The simulation consists of a geometric definition of the model domain (the mesh) and a set of numerical parameters. The parameters define the boundary conditions and options pertinent to the model.

The interface is accessed by selecting the 2D Mesh Module and setting the current model to FESWMS. If a mesh has already been created for a FESWMS simulation or an existing simulation read, the mesh object will exist in the Project Explorer and selecting that object will make the 2D Mesh module active and set the model to FESWMS. See the Mesh Module documentation for guidance on building and editing meshes as well as visualizing mesh results.

The interface consists of the 2D Mesh module menus and tools augmented by the FESWMS menu. See FESWMS Graphical Interface for more information.


When completing a File | Save As... command the following files get saved in the *.sms.

  • *.fpr referenced to new save location
  • *.mat referenced to new save location
  • *.flo referenced to original location unless reran then moves to saved location.

Related Topics


  1. ^ Sept. 2002 - User’s Manual for FESWMS Flo2DH - Publication No. FHWA-RD-03-053

External Links

  • FESWMS FST2DH User’s Manual PDF (Revised Oct 2003)
  • U.S. Department of Transportation Federal Highway Administration – Hydraulics Engineering Software Page [1]
  • Ipson, Mark K. (2006). Analysis of the Sediment Transport Capabilities of FESWMS FST2DH. Thesis, Brigham Young University. [2]