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SMS Technical Information

The Surfacewater Modeling System (SMS) is a comprehensive graphical user environment for two-dimensional hydrodynamic modeling. SMS provides tools for mesh and grid generation, data interpolation, and sophisticated tools for graphical visualization. SMS was developed in cooperation with the U.S. Army Corps of Engineers, WES and the U.S. Federal Highway Administration (FHWA).

Available Modules

The SMS software package is divided logically into five well-integrated, task-oriented modules. These modules are: 2D Mesh, 2D Boundary Fitted Grid, 2D Scatter Point, Map, and River.

2D Mesh Module

The 2D Mesh Module is used to construct 2D finite element meshes. A variety of tools are provided for automated mesh generation and mesh editing. In SMS, 2D meshes are used to generate models for both the TABS suite of software and the FESWMS analysis package.

2D Grid Module

The 2D Boundary Fitted Grid Module will be used to construct 2D boundary fitted grids. This module will be available in the next release of SMS and has been included in this version to facilitate future expansion.

2D Scatter Point Module

The 2D Scatter Point Module is used to interpolate from groups of 2D scattered data points to any of the other data types. For example, the user may gather field data points representing the bathymetry of the region to be modeled. The elevation data from these points can be interpolated to w well structured set of elements to create the bathymetry of the entire mesh.

Map Module

The Map Module is used to manipulate four types of objects. The first three objects: DXF objects, image objects, and drawing objects are primarily used as graphical tools to enhance the development and presentation of a model. The fourth type of object, feature objects, are used to construct high-level conceptual models. Once a conceptual model is constructed, it can automatically be converted to a numerical model.

River Module

The River Module allows the creation of cross sections of rivers. SMS is taking the first steps in integrating the use of traditional modeling of rivers using one-dimensional analysis with topographic models. Tools are provided to define bridge openings, culverts, guidebanks, and roadways at the cross sections. If a topographic representation of the site has been modeled in SMS, the cross section information data can be extracted. Tools are also being developed to create a topographic model from a user defined centerline and the cross sectional information used by the one-dimensional model. These tools will allow integration of one- and two-dimensional modeling.

Supported Models

The SMS software package provides an interface to five models. These models are: ADCIRC, CGWAVE, FESWMS, GFGEN, HIVEL2D, RMA2, RMA4, RMA10, SED2D, STWAVE, and WSPRO.


ADCIRC is a numerical model developed for the specific purpose of generating long time periods of hydrodynamic circulation along shelves, coasts, and within estuaries. The intent of this model is to produce long numerical simulations for very large computational domains in a unified and systematic manner.


CGWAVE is an advanced wave prediction model under development for the Office of Naval Research, Army Corps of Engineers, and NOAA. The model simulates wave refraction, diffraction, reflection (by coastlines, structures, and the bathymetry), nonlinear dispersion, and dissipation due to friction and breaking for a wide spectrum of input wave frequencies and directions.


FESWMS is a hydrodynamic modeling code that supports both super and subcritical flow analysis, including area wetting and drying. The FESWMS model allows users to include weirs, culverts, drop inlets, and bridge piers in a standard 2D finite element model.


GFGEN’s purpose is to create geometry and finite element mesh files for input to the RMA2 2D hydrodynamic numerical model.


HIVEL2D is a free-surface, depth-averaged, two-dimensional finite element model designed specifically to simulate flow in typical high-velocity channels. HIVEL2D is applicable for flow fields that contain supercritical and subcritical regimes as well as the transitions between the regimes. The model provides numerically stable solutions of advection- dominated flow fields containing shocks such as oblique standing waves and hydraulic jumps.


RMA2 is a two dimensional depth averaged finite element hydrodynamic numerical model. It computes water surface elevations and horizontal velocity components for subcritical, free-surface flow in two dimensional flow fields. RMA2 computes a finite element solution of the Reynolds form of the Navier-Stokes equations for turbulent flows. Friction is calculated with the Manning’s or Chezy equation, and eddy viscosity coefficients are used to define the turbulence characteristics.


RMA4 is a finite element water quality transport numerical model in which the depth concentration distribution is assumed uniform. It computes concentrations for up to 6 constituents, either conservative or non-conservative, within the computational mesh domain.


RMA10 is a multi-dimensional (combining 1D, 2D either depth or laterally averaged, and 3D elements) finite element numerical model written in FORTRAN-77. It is capable of steady or dynamic simulation of three dimensional hydrodynamics, salinity, and sediment transport. It utilizes an unstructured grid and uses a Galerkin based finite element numerical scheme.


SED2D is the name for the sediment transport numerical model developed by the U.S. Army Corps of Engineers Waterways Experiment Station. It has the ability to compute sediment loadings and bed elevation changes when supplied with a hydrodynamic solution computed by RMA2.


STWAVE (STeady State Irregular WAVE Model) provides an easy-to-apply, flexible, and robust model for nearshore wind-wave growth and propagation. It simulates depth- induced wave refraction and shoaling, current-induced refraction and shoaling, depth- and steepness-induced wave breaking, diffraction, wave growth because of wind input, and wave to wave interaction and white capping that redistribute and dissipate energy in a growing wave field.

River Module

The River Module allows the creation of river cross-sections. SMS is taking steps to integrate the use of traditional 1-D river modeling with 3-D topographic models. Tools are provided to define bridge openings, culverts, guide banks, and roadways at cross-sections. If a topographic representation of the site is available, the cross-section information data can be quickly extracted. Tools are also being developed to recreate a 3-D topographic model from a user-defined centerline and the cross-sectional information used by the 1-D model. These tools will allow integration of 1-D and 2-D river modeling.

Map Module

In order to facilitate a new conceptual model approach to numerical model design, a new module called the Map Module has been added to SMS. Four types of objects are supported in the Map Module: DXF objects, image objects, drawing objects, and feature objects.

The first three objects: DXF objects, image objects, and drawing objects are primarily used as graphical tools to enhance the development and presentation of the conceptual model. DXF Objects consist of drawings imported from standard CAD packages such as AutoCAD or MicroStation. Externally produced site drawings can often provide a useful backdrop or supplement to the graphical desktop during model construction. Drawing Objects are essentially a simple set of graphical tools that allow the user to draw text, lines, polylines, arrows, rectangles, and other symbols to add annotation to the graphical representation of a model. Image Objects are digital TIFF images representing aerial photos or scanned-in maps. TIFF files can be imported and registered to real world survey coordinates. Construction of the conceptual model can then be accomplished using a high resolution background image.

The fourth type of object, Feature Objects, are used to construct the actual conceptual model. Feature objects are patterned after the data model used by geographic information systems (GIS) such as ArcInfo, ArcVIEW, and MapInfo. The GIS data model utilizes points, arcs (polylines), and polygons to represent spatial information. For example, a point can represent data such as specified head, velocity, and finite element mesh refinement location; an arc can represent flow boundary data such as specified head, flowrate, and sediment load; and a polygon can represent areal (i.e., zonal) data such as material type, roughness, and mesh generation method (either patch or adaptive tesselation). Sets of points, arcs, and polygons can then be grouped into separate layers or coverages. A set of coverages then provides a complete description of the conceptual model.

Once the conceptual model has been defined, the next step is to develop the numerical model (i.e., 2-D finite element mesh along with interior and exterior boundary conditions) from the conceptual model. If the user decides to change the conceptual model (i.e., adjust a flow boundary, change a material type, adjust the mesh refinement, etc.), these changes can be quickly made to the corresponding conceptual model feature objects and a new numerical model regenerated within seconds.

There are two principal advantages to the conceptual model approach used in SMS. First, generation of the numerical model is much more efficient. The modeler can focus on high level representations of the site rather than on a discretized representation of the site. Thus, data entry is greatly simplified. Second, the overall modeling process is greatly enhanced using the conceptual model approach. If a calibration attempt fails and a modification of the conceptual model is needed, the modification to the conceptual model can be quickly made and a new numerical model regenerated immediately. This makes it possible to evaluate numerous candidate conceptual models quickly and cheaply. As a result, the final numerical model is typically much more accurate.

Model Visualization

SMS has coupled the most advanced flow and transport codes available with the state-of-the-art in scientific visualization. SMS includes two-dimensional contour plots of meshes and vectors. Once a modeling study is complete, several options are available in SMS for generating graphical output for illustration and to include in a final report of the modeling study. These options are animation, printing, annotation, exporting DXF or TIFF files, and copying images to the clipboard.


The only way to truly visualize transient solutions is by utilizing animation. The SMS film loop tool enables generation of flow traces as well as rapid generation of animations with two-dimensional direction and magnitude of water flow and sediment transport over time. The Microsoft Windows version of SMS builds film loops using Microsoft Windows AVI format.

Animations are generated in SMS to show how a functional value, such as the water velocity magnitude or water depth, varies for the entire mesh through time.

On the PC platform, SMS now generates graphical animations in the Windows® AVI format. AVI has become the multimedia standard in the personal computing world. Many utilities are readily available to allow you to add enhancements to AVI files, such as background music. In addition, AVI files can be embedded within computer generated presentations, such as from Microsoft PowerPoint®.

A flow trace is an animation which traces the path particles of water will follow in the model. A flow trace can be generated from a steady-state or a dynamic (time dependent) model.


Images can be printed by selecting the Print command in the File menu. On the PC, this prints the image to the currently selected printer. On Unix, a color or black and white postscript file is created which can then be sent to a printer.


Before printing an image or copying the image into another document, it is often useful to add annotation to the image in order to provide a title or highlight important features. Annotation can be added with the drawing tools provided in the Map Module. The annotation tools can be used to create text, lines, arrows, rectangles, and ovals.

Exporting a DXF or TIF File

Images can be exported to a DXF file by selecting the Export command in the File menu and selecting the DXF option. The DXF file can then be imported to a CAD package such as AutoCAD or MicroStation for editing or inclusion with other drawings in a final report. An image can be exported to a TIFF file by selecting the Export command in the File menu and selecting the TIFF option. TIFF files are bitmap type image files and can be imported to most graphics programs.

Windows Clipboard

On the PC, the simplest way to include a SMS image in a drawing or document in another application is to use the Windows clipboard. Selecting the Copy command in the Edit menu copies the currently displayed image as a vector image to the clipboard. This image can then be pasted into a document in another application by positioning the cursor where you want the image to be located and selecting the Paste command in the Edit menu of the other application.

Scatter Point Module

Scatter Point Module The Scatter Point Module is used to interpolate from 2-D scattered point data to finite element meshes. For example, the user may gather field data points representing the bathymetry of the region to be modeled. This elevation point data can then be interpolated to define the complete finite element bathymetry of the area to be modeled.

A variety of interpolation methods are provided with the Scatter Point Module, including Linear, Inverse Distance Weighted, Clough-Tocher, Natural Neighbor, and Kriging.

1-D Element Support

SMS now supports creation of 1-D elements with use with 2-D finite element meshes. This allows the modeler to more quickly develop models by being able to represent inflow streams using 1-D channels that transition into the 2-D mesh. 1-D elements can be used as junction nodes, or as flow control nodes to model weirs and culverts for use with RMA2.