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WMS provides complete support of the industry-standard U.S. Army Corps of Engineers
HEC-1 and HEC-HMS, U.S. Soil Conservation Service TR-20 and TR-55, and Rational Method Equation hydrologic routing programs. Also supported the National Flood Frequency (NFF) model, which was developed by the USGS
in cooperation with the Federal Highway Administration (FHWA) and the Federal Emergency Management Agency (FEMA). In addition, support for the EPA/USGS hydrologic water quality HSPF model is also provided.
The program's modular design enables the user to select modules in custom combinations, allowing the user to choose only those hydrologic modeling capabilities that are required. Additional WMS modules can be
purchased and added at any time. The software will dynamically link to these subsequent modules at run time—automatically adding additional modeling capability to the software.
Graphical User interface
Thanks to the graphical tools of WMS, with standard MS Windows functionality, building models and viewing results is very easy and intuitive. All
modeling parameters are entered through interactive graphics and easy-to-use dialog boxes. Though the software reads and writes native model input/output files, there is no need to worry about formatting text files
to get the models to run nor will you need to search through text output files to find the results from the model run.
Thanks to simple CAD/GIS style tools and functionality, you will find that manipulating
digital terrain data and GIS data to delineate watersheds and compute model input parameters is very smooth. Further, presentation of results of your work will be impressive and easy to understand.
Graphics and Visualization
WMS is a powerful graphical tool for model creation and visualization of results. Models can be built using digital maps and elevation models for reference and source data. During the model building process, the graphical representation of the model allows quick review and presentation of your work. Fully 3D views, with contouring and shading, of your model allow anyone to see and understand the domain and parameters of your analysis.
Watershed display options include elevation contouring, basin-boundary outline or color fill, streams, time of concentration flow path plotting, base map (orthophotos, USGS Quad maps, etc.) rendering, and
many others. Watershed data such as areas, slopes, flow distances, basin centroids, etc. can be displayed as well. Model results such as hydrographs can be plotted with a variety of plotting options.
Further, floodplain results can be reported as flood depth maps, flood extent maps, and flood impact maps - all scalled and reported in real-world coordinates.
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WMS Modules
The WMS interface is separated into several modules; these modules contain tools that allow
manipulation and model creation from different data types. The modules of WMS are:
Map Module
DEM Module
TIN Module
Hydrologic Modeling Module
Scatter Point Module
2D Grid Module
Map Module
The Map Module in WMS allows you to use GIS or CAD data, as well as TIFF or JPEG image
data, to create and enhance visualization of your watershed models. Images (such as USGS quad maps or aerial photographs) can be used in WMS as a reference for digitizing features in
your model or as a backdrop to enhance model presentation. With GIS data, CAD data, or data you have digitized yourself in WMS (such as land use or soil type data), you can assign
parameters and boundary conditions to your model in a quick and intuitive manner. WMS will allow you to build a complete watershed model with map data.
The Map Module of WMS allows you to use data from many other software systems. The file formats that WMS can read/write for this type of data are:
ArcGIS Shapefiles
USGS DLG files
CAD DXF files
Georeferenced or regular TIFF files
Georeferenced or regular JPEG files
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The Map Module is also an important component of auotmated watershed delineation in
conjunction with the DEM Module or the TIN Module of WMS. Watershed outlet placement, stream representation, and basin boundary representation are accomplished with the Map
Module when used in conjunction with the DEM Module. When used with the TIN Module, the Map Module allows placement of breaklines, controls mesh (surface triangulation density, and
placement of outlet points in a watershed.
DEM Module
The DEM module is used to import and manipulate Digital Elevation Models (gridded elevation
data files) for use with watershed modeling. WMS can import/export several formats of DEM data including:
USGS DEM files (*.dem or SDTS format)
ARC/INFO ASCII Grid files
NED files
GRASS grid files
DTED grid files
These data formats can be read into WMS and displayed with contours or hill-shades - all in fully 3D rotated views.
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DEM processing tools in WMS allow you to automatically delineate streams and
watershed/sub-basin boundaries based on the land surface represented by the DEM. One of the best features of WMS is the flexiblity and control you have when using the DEM-based
delineation method. You can use any stream network (automatically generated or manually digitized) in conjunction with a DEM to delineation draininge areas. You can also manipulate
wateshed boundaries generated by WMS or create them entirely on your own and let WMS match the DEM data with the watershed delineation you know is correct.
TIN Module
The TIN module is used for terrain modeling, automated basin delineation, and floodplain
delineation in WMS. TINs (Triangulated Irregular Networks) are formed by connecting a set of xyz points (scattered or gridded) with edges to form a network of triangles. Points used to create TINs
can be obtained by digitizing a contour map (or a scanned image inside of WMS), or generated automatically from feature arcs and polygons, using DEMs or existing TINs as background
elevation maps. TINs can be contoured, displayed in oblique view with mapped images and hidden surfaces removed, and several other display options that can be set to visualize and
understand the terrain surface better.
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WMS can analyze the surface of a TIN and quickly determine drainage features such as stream
channels and watershed boundaries. A complete watershed model can be contructed using only a TIN in WMS if desired. Basin and routing parameters such as slopes, distances, flow paths,
etc. can be automatically determined from a TIN. Further, flooding can be easily determined given a TIN and a few points of water surface elevation in a stream. Flood extents and flood
depths can be quickly generated and displayed using a TIN in WMS.
Hydrologic Modeling Module
The Hydrologic Modeling Module, sometimes refered to as the Tree Module, is the center for
modeling input, execution and output review. Each model supported by WMS has a complete interface in this module. The model interfaces allow you to view and edit model input parameters
quickly and easily. The watershed models built using the Map, DEM or TIN Modules are linked to a simple schematic (tree) representation in the Hydrologic Modeling Module. This allows you
to quickly select and edit basin parameters and stream (reach) parameters.
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Further, native model files (such as HEC-1 files) can be read in or written out from this module.
WMS allows you to use model files created in other systems or by hand by reading in the modeling information and building a schematic representation (tree) for you to use as you update
or review the model. You can save any model back to a native file format - including the new HEC-HMS format.
The Hydrologic Modeling Module also contains the tools for computing complex hydrologic
parameters (using your digital terrain or GIS data) needed for input to a model. This functionality includes:
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Time of Concentration Computations
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Calculate Tc based on basin-data based regression
equations (such as the SCS Lag Time equation) or use equations assigned to actual flow paths, subdivided into flow regimes (sheet flow, channel flow, etc.) as recommended by the FHWA or
TR-55 Tc Methods.
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Curve Number (CN) Calculations
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Overlay Land Use and Soil Type data on your watershed
and let WMS compute an area-weighted CN for each basin.
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Green & Ampt Calculations
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Overlay Land Use and Soil Type data on your watershed
and let WMS compute average Green & Ampt parameters for each basin.
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Rainfall Depth Mapping
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Use a iso-pluvial grid or map to allow WMS to compute
an area-weighted rainfall depth for each basin.
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HSPF Segment Mapping
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Overlay Land Use data to divide your HSPF model into
different pervious and impervious land segments.
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Runoff Coefficient Calculations
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Overlay Land Use or zoning data to determine
area-weighted runoff coefficients (C) for use with the Rational Method.
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Once a model has been completed, tools in this module allow you to open flow results (peak flow
reports, hydrographs, etc.) and plot them with your model. You can also export model results to more useful formats (spreadsheets, tables. etc.) from this module. Anyone who has tried to sort
through a complex model output file will appreciate this functionality.
Finally, the Hydrologic Modeling Module contains several ``Calculator" tools for colculating
modeling input or analyzing model output. These include:
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Detention Basin (Reservoir) Calculator
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Create Storage-Capacity-Dischage curves based on simple
geometry or land surface contours. You can then route any hydrograph through a detention basin or use these curves as input to HEC-1, TR-20, MODRAT, or the Rational Method.
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Culvert Calculator (HY-8)
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Set up and run a full culvert analysis using the HY-8
analysis engine created by the FHWA.
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Weir Calculator
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Perform simple computations to determine flow over a
weir given a head value or determine head on a weir given flow.
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Open Channel Calculator
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Use generalized cross-sections (trapezoidal, circular,
etc.) or a custom cross section (station/elevation points entered into WMS or cut automatically by WMS from a land surface model) to compute flow, depth, Frounde Number, critical depth,
etc.
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Curb & Gutter Calculator
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Use the method recommended by the FHWA for gutter
analysis and inlet design.
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Scatter Point Module
The Scatter Point Module is used to interpolate from groups of scattered data points to the other
data types (i.e., TINs). WMS supports three interpolation schemes including linear, natural neighbor and inverse distance weighted. The module is also used to view and edit survey data.
Interpolation from scatter data is used primarily for floodplain delineation in WMS. Flood stages can be input anywhere on a scatter data point; WMS then uses interpolation to ``fill" the floodplain
and compute extents and depths.
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2D Grid Module
The Grid module is used for surface visualization and for the development distributed (2D)
rainfall/runoff analytical models. For example, the user can discretize a watershed into a number of grid cells and then define important rainfall, infiltration, and channel properties at grid cells in
preparation for running a 2D model. Any parameter such as hydraulic conductivity or rainfall intensity may be interpolated from a set of scattered data points to the grid. Results of the 2D
analysis can then be contoured on the grid or displayed with hidden surface removal and color fringes to display the variation in the computed results.
The 2D Grid Module is primarily used by the US Army Corps of Engineers and some other reseach institutions due to the fact that the models supported (GSSHA or CASC2D) are not yet available to the public.
WMS Models
The Watershed Modeling System supports several industry-standard, numerical models to
compute peak flow, hydrographs, water quality, etc. Each model is supported through the Hydrologic Modeling Module with a completely integrated interface for parameter input, job
control, and output review. A model checker is also featured with each model; this checker guides you to correct errors or omissions in model input data. The models available for use with
WMS are described below - each model is included with the WMS installation (model executable files and documentation) and is fully linked with the WMS software.
HEC-1 (HEC-HMS)
TR-55
TR20
Rational Method
National Flood Frequency (NFF)
HSPF
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