Aquaveo & Water Resources Engineering News

Tips for Building a CE-QAUL-W2 Model

Are you building a CE-QUAL-W2 model in WMS? CE-QUAL-W2 is a 2D laterally averaged hydrodynamic and water quality model. It can model vertical variance, eutrophication, seasonal turnover, algal blooms, etc. if incoming pollutants are known. Setting up a CE-QUAL-W2 simulation involves dividing the reservoir into segments, branches, and layers and determining the geometric properties of each segment, branch, and layer.

When building a CE-QUAL-W2 model, keep the following in mind:

  • Make certain that the site you have chosen is appropriate for the CE-QUAL-W2 numeric model. It is best applied to long and narrow water bodies that have longitudinal and vertical water quality gradients. The further your site location deviates from a long and narrow water body, the less ideal it is to CE-QUAL-W2.
  • Example of smoothing an arc for a CE-QUAL-W2 model
  • When setting up branches, you may need to remove smaller branches and offshoots. This may particularly be the case if you used the TIN Boundaries to Features command. Using this command can end up including small branches and offshoots that are unnecessary for the final model. Each branch should be examined and judgment exercised on the importance of including it in the model. To remove the unnecessary branches, smooth out the bounding polygon.
  • Before smoothing out a bounding polygon, it is recommended that you duplicate the original map coverage in order to retain the original coverage data. Then use the map tools to smooth out the bounding polygon for the coverage that will be included in the model. Remove any extra coverages when you finish smoothing the bounding polygon.
  • Verify that all segments are measured and assigned correctly. This is done by double-clicking on any segment in the segment coverage and using the Polygon Segment Attributes dialog to review each of the segments. Either enter values for segments that are missing attributes or remove the segment.
  • Review branches through the Polygon Branch Attributes dialog. This is accessed by double-clicking on any branch in the branch coverage. Make certain to enter values for all branches.

Using the tips above can help assure that your CE-QUAL-W2 model executes correctly. For additional support, contact our technical support staff. Try out CE-QUAL_W2 in WMS today!

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Understanding SRH-2D Obstructions

Do you have an SRH-2D project that might benefit from using obstruction objects? The obstruction coverage in SMS allows you to add obstruction objects to your SRH-2D project. Using obstructions in some cases can be beneficial, but there are a few key ideas to keep in mind. This post will cover some of these.

Adding obstructions to an SRH-2D project involves creating a coverage assigned as an SRH-2D obstruction type coverage. On this coverage, you can draw arcs and points to act as obstruction objects. Each arc and point can be assigned obstruction attributes. Finally, the obstructional coverage can be added to the SRH-2D simulation to be used in the model run.

Example of the SRH-2D Assign Obstructions dialog

First, it is important to understand how obstructions interact with the model run. Obstruction objects on the obstruction coverage will reduce the flow of water through the model by applying a drag force. Water will not flow around the obstruction but will instead be slowed by the drag force of the obstruction. The assigned attributes on the obstruction object will determine which cell nodes on the mesh will be assigned as an obstruction. Obstructions can be used for items like bank protrusions and boulder clusters.

Second, when assigning obstruction attributes to an obstruction object, a width/diameter is specified in SMS. For point obstructions, this user-specified value is then converted by PreSRH-2D to a radius for SRH-2D. The SRH-2D model applies the radius around the point. For line obstructions, the arc definition and width are converted by PreSRH-2D to point locations that define the obstruction area. That means, for example, if you assign an arc to have an obstruction width/diameter value of 2 meters, then 1 meter on one side of the arc and 1 meter on the other side of the arc will be the obstruction area.

Third, obstruction objects can be assigned a drag coefficient, porosity, and a specific thickness. It is important to note that obstruction objects are not meant to completely impede the flow of water.

For items that completely block the flow of water, such as bridge piers or buildings, a void in the mesh should be created that models the area of blockage in most cases. Likewise, having a large number of obstruction objects in your model sometimes can cause issues with the SRH-2D model run and therefore it is recommended that obstruction objects be used judiciously.

Obstructions can be a valuable addition to your SRH-2D model. Try using obstructions with SRH-2D in SMS today!.

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Defining Hydraulic Conductivity for Specific Layers

In your groundwater model, do you need to define hydraulic conductivity for specific layers differently than other layers? Do you need to modify the hydraulic conductivity values for specific areas within a single layer? GMS provides more than one way to assign hydraulic conductivity. This capability gives you more precision with regard to how hydraulic conductivity is assigned to your groundwater model.

Using the conceptual model approach, hydraulic conductivity can be assigned to polygons on a single coverage then mapped to your model. You can also use multiple coverages, assigning the hydraulic conductivity to specific layers ranges. The workflow for this is as follows:

  1. Right-click on the coverage and select "Coverage Setup...".
  2. In the "Default Layer range" set the layer range you would like to use.
  3. Coverage setup for conductivity on a specific layer
  4. Select the coverage to make it active.
  5. Double-click on a polygon within the coverage.
  6. It will bring up the attribute table for that group of layers.
  7. Set the conductivity for the polygon.
  8. Repeat this process for each desired group of layers.

When using this workflow, take care to make certain you are setting the correct attributes to the correct layer of your grid. Naming the coverage with the layer number or layer range can help with this process. You may also want to use the notes feature to attach reminders as to how the coverage has been set up.

It should be noted that when mapping multiple coverages to your grid, GMS follows an order of priority for the coverages. If you have different conductivity values on different coverages that overlap it is recommended that you apply the coverages individually. The last coverage that you apply will overwrite any overlapping values. If you apply all the coverages at once, the conductivity values will be summed up in areas where they overlap.

Try out using multiple coverages to define hydraulic conductivity for specific layers in GMS today!

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Using the Database Import Wizard in WMS

Do you have data stored in a database that you would like to import into your WMS project? Occasionally you might find yourself with a database that needs to be imported into your WMS project. This might be a geodatabase or some other sort of database containing GIS data that WMS does not recognize natively.

To import a database, WMS uses the Import Database Wizard. The wizard is accessed through the Import From Database command in the File menu. Once the wizard has been launched, there are a few steps you need to follow.

  1. Connect to a database. Use the Connect to Database button to connect to a database located on your computer or on a network. A preview of the database will be displayed in the tables in the wizard.
  2. The Import Database Wizard
  3. Query information from a database table. You will have the option to create, copy, delete and import queries that retrieve data from the database. The query uses basic SQL statements which can be entered in the provided fields.
  4. View results of the query. The results of the database query are displayed for you to review. If the results are not what you expected, you will have the option to return to the previous step to fix the issues.
  5. Assign column type. You can select the kind of data that will be imported into WMS. The kind of data should be of the file types supported by WMS. There is also the option to set files as "no data".

After the data has been imported into your project, you can make use of the coordinate transformation tools in WMS to transform or translate the data if necessary.

If you have a database with data you would like to import into WMS, try using the Import Database Wizard in WMS today!

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Understanding the Smooth Datasets Tool in SMS

Do you have a dataset, or survey data, that has random distances between points which you would like to have a more uniform distribution? SMS contains a tool that allows you to smooth data. By using the Smooth Datasets tool you can create a new dataset that has a more even distribution.

To use the Smooth Dataset tool, do the following:

  1. Make certain you have the Scatter module containing the dataset active. If your dataset is in a different geometry, it may need to be converted to a scatter set.
  2. Use the Dataset Toolbox command in the Data menu to open the Dataset Toolbox.
  3. Select the Smooth Dataset tool under the list of tools.
  4. Enter the parameters for smoothing the dataset.
The Smooth Datasets tool in the Dataset Toolbox

When using the Smooth Dataset tool there are a few items to keep in mind:

  • There are no restrictions related to X or Y point distribution. In other words, the dataset points don’t need to align with a grid.
  • The "Element Area Change" option is only recommended when smoothing size functions for certain meshing methods (i.e. scalar paving).
  • When smoothing elevations, the "Maximum slope" method is recommended. This function works with any scalar dataset, but I will assume elevation as the dataset for this explanation.
  • When using the "Maximum slope" method, the elevation of a starting point is compared with its neighboring points (connected via triangles). The elevation of a neighboring point is adjusted if the slope between the points exceeds the specified maximum.
  • The "Anchor type" determines the starting point.
  • If "Minimum value" is selected, SMS starts at the point with the lowest elevation, and the elevations of its neighboring points are adjusted if necessary. SMS then continues to the point with the next lowest elevation.

The Smooth Dataset tool can help you resolve issues with raw data and help your model be more efficient. Try out the Smooth Dataset tool in SMS today!

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How to Export Contour Lines as Shapefiles

Have you been wanting to export the contour lines in your GMS project as a shapefile so they can be opened in a different application? GMS allows exporting contour lines as a shapefile. Shapefiles are a file format used by many different GIS software applications. This post will explain how to export contour lines as shapefiles.

GMS contains the Layer Contours → Shapefile command to help save contour lines as a shapefile. Using this command requires your project to be set up correctly. Use the Layer Contours → Shapefile command by doing the following:

  1. Make sure the contours you want to convert to a shapefile are set to Linear in the Display Options. This can be accomplished by opening Display Options and clicking on Contours. In the Contour Method in the top left make certain in the dropdown that it is set to Linear.
  2. Make sure your Grid module is active in GMS, this can be done by clicking on the grid in Project Explorer or selecting the Grid module macro. The grid should be highlighted, meaning that it is now active.
  3. Go to the Grid menu and select the Layer Contours → Shapefile command. Use the dialog that appears to save your shapefile. Be sure to place it in the correct folder and name it properly. Otherwise you might lose the file.
  4. Now open your shapefile in the appropriate GIS software. The contour lines will appear as arc lines.
The Contour Lines to Shapefile Command

If you encounter issues with the shapefile, start with checking the folder where you saved the file. Make certain that all of the necessary files for the shapefile are there, including a projection file. Another item to check is that everything you want in the shapefile is displayed correctly in the Graphics Window before you export. Use the display options to adjust the contour lines if needed. Finally, there may be some differences between how GMS displays a shapefile and how other GIS applications display the shapefile. Opening the shapefile in GMS can help you determine if this is the case.

Try out converting contour lines to shapefiles in GMS today!

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Using Arc Annotations in SMS

Have you been wanting to have more contextual information for your arcs in SMS? Some projects require being able to easily tell which direction arcs are flowing or quickly see the distance of arcs. With the release of SMS 13.1, you may have noticed an addition to the display options that can help with this. The Arc Annotations options can provide additional contextual information to arcs in your SMS projects. This post will review how they can be accessed, and how they can help you while modeling in SMS.

The options for arc annotations are contained within the Map tab of the Display Options dialog. The Map tab can be accessed either by selecting Map from the list within Display Options, or by right-clicking on Map Data in the Project Explorer and selecting the Display Options… command. Once in the Map tab, the Annotations option can be turned on, which will then activate an Options… button. Clicking this button will bring up the Arc Annotation Options dialog where the new arc annotation options can be selected.

The main options that can be set here involve direction and ticks. Direction will show arrows on arcs to indicate which direction they are flowing. Ticks will show tick marks on arcs to indicate length measurements, which can help in visually seeing the real-world length of arcs. There are multiple options when it comes to how ticks will be displayed, giving you flexibility for your specific needs when it comes to modeling. It is important to note, however, that ticks will only display if the project units are set to feet or meters.

Example of the arc annotations

These features can be valuable in projects where the added visual cues and references can help with more instantaneously interpreting the graphical data. The customizability for tick display will also allow for the optimization of making this information look as presentable as possible within the model. For more details on the options available when using arc annotations, visit the XMS Wiki to learn more!

Try out using arc annotations in SMS 13.1 today!

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New Features in GMS 10.6 Beta

Aquaveo is pleased to announce the release of the Groundwater Modeling System version 10.6 in beta! With this beta release, GMS contains changes and improvements to various features, much of it involving increased support for MODFLOW 6 functionality. We’d like to highlight some of the new functionality you can expect to find in GMS 10.6 beta.

Transport Support for MODFLOW 6

GMS 10.6 beta adds the ability to work with transient models for MODFLOW 6, as demonstrated by the addition of transport packages relevant to the GWT (Groundwater Transport Model) package. These will be helpful to many different aspects of groundwater transport modeling, such as dealing with advection, constant concentration, and dispersion. With the wealth of packages this alone adds to GMS 10.6 beta, it will add a lot of functionality to what GMS can do with MODFLOW 6 simulations.

Example of the new MODFLOW 6 Simulation dialog
Increased GWF Package Support MODFLOW 6

In addition to the suite of transport-related packages that GMS 10.6 adds to work with, support has also been added for more packages relevant to the GWF (Groundwater Flow Model) package. In this case, this includes the addition of the BUY (Buoyancy) and CSUB (Skeletal Storage, Compaction, and Subsidence) packages. The addition of these packages will help flesh out what GMS 10.6 beta can do with MODFLOW 6 simulations.

Support for Exchanges in MODFLOW 6

Support has also been added in GMS 10.6 for exchanges. These include the GWF-GWF and GWF-GWT exchanges. These can be used to help different models in a GMS project interact, and designate the nature of how they should interact. GWF-GWF exchanges can help two different GWF models interact together and hydraulically connect, telling each model that there is flow along a shared edge. GWF-GWT exchanges can help designate which GWF and GWT models should interact with each other.

These are just a few of the new features and changes coming out as part of the release of GMS 10.6 beta. You can find more information on what will be introduced in GMS 10.6 beta by going to the Aquaveo XMS Wiki. Try out these features and more by downloading GMS 10.6 beta today!

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Making Use of WMS Contour Labels

Does your watershed project need to display contour elevations values? WMS (as well as SMS and GMS) have the ability to use contour labels to help determine elevation levels at a glance, which can be very helpful for many projects, especially when modeling drainage. This post will review the different ways that contour labels can be utilized within WMS.

Example of contour labels

There are essentially two different forms or methods when it comes to applying contour labels to contours when working in WMS: manual and automatic. In both cases, the way contour labels are displayed can be modified in the Contour Label Options dialog, which can be accessed by clicking the Label Options… button when the Contour Options dialog has been brought up. Here there are options for color, orientation, font, scientific precision, etc. There is also a button to "Erase all existing contour labels" and start over from the beginning.

The manual method consists of using the Place contour label tool to click on contours and manually assign contour labels to the positions the user chooses. This option is only available in certain modules, such as 2-D Grid and Terrain Data. Note that these may disappear when options in the Contour Label Options dialog are modified, so it may be best to determine the contour options before you manually place contour labels. Labels can also disappear when contouring options are changed, when the Graphics Window is refreshed, or can even be manually deleted when holding down Shift and clicking on a label with this tool active.

The automatic method consists of using the Automatic Labels section in the Contour Label Options dialog to automatically populate labels along the contours. When activated, this allows you to set how many of the contours should be labeled, which contour to start with, and how far apart the labels are spaced out. Unlike in the manual method, changing options for these labels should not delete them, as they should automatically repopulate based on current settings when the OK button is clicked to close the Contour Label Options dialog.

While every project will be different, when using contour labels, some recommended settings to start off with would be to use "Color Fill and Linear" as the Contour Method, and to automatically space out labels. This way more discrete contours as well as gradient values can be easily displayed and it will be easy to determine at any given location what the elevation is. Also recommended is to avoid using white text in most instances, as it is usually difficult to read, except perhaps in instances where color fill is used.

Try out experimenting with contour labels in WMS 11.1 today!

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Best Practices for Extracting Features

Have you used the Extract Features tool in SMS before? The Extract Feature tool lets you generate channel and bank arcs from elevation data. There are some tricks to optimizing the use of this tool. This post will review some of the best practices that you should follow when you extract features from elevation data in SMS.

Digital Dams
Example of a digital dam

These are often artifacts from stamping channels or unprocessed LIDAR data and they can cause problems determining flow directions on the raster. The pre-processing engines (TOPAZ and TauDEM) fill these prior to computing flow directions, which can be a problem if the centerline strays from the thalweg and matching depth is computed off of the filled raster and not the original, which will also cause higher elevations along the channel above the dam. These can be fixed by either:

  • Trimming the raster above the dam by right-clicking on the raster and selecting Convert To | Trimmed Raster using a Map Module polygon.
  • Modifying elevations downstream of the dam to match correct stream thalweg elevations by right-clicking the raster and selecting Editing | Edit Raster using selected arc elevations.
Placing Points for Extracting Bank Features

When extracting bank features, place the point closest to the most important area. For example, if a section is being used for bridge analysis, place the point close to the bridge. This allows the bank lines to stay the closest to the original feature. If the Extract Bank tool misses a bank section, try moving the point to the missed section and run it again.

Extracting Centerlines for Braided Streams

When extracting centerlines for braided streams, sometimes they may not follow the actual stream location because of digital elevation model inaccuracies. When this happens, extract both centerlines and manually merge the arcs into a single arc after both centerlines have been extracted.

Use the Depth That Is Option

The following guidelines should be observed when using the "Use the depth that is" option:

  • If there is a single well-defined channel with a strong bank feature, use the "Closest to centerline" option.
  • If there are multiple floodplain bank features, use the "Closest to previous" option, otherwise, the Extract Features tool may catch a different floodplain feature.
  • If there are multiple channels or a braided stream (and you want to catch the widest extents of the channel), use the "Furthest from centerline" option.

Try out some of these best practices while extracting features in SMS 13.1 today!

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