Aquaveo & Water Resources Engineering News

Accessing 3DEP Data for SMS

The Surface-water Modeling System (SMS)[2] continues to expand the types of data it can use for your water modeling projects. For models in the United States, there is a very comprehensive set of elevation data that you can use in your modeling–3DEP data.

3DEP data is an amalgamation of high-resolution 3D elevation and 3D hydrography data from multiple sources. It is also "bare earth," meaning the images are ground-level only. No buildings, trees, shrubs, or ground cover of any sort have been included. Seeing the most precise shape of the ground can be very important to surface modeling. The high quality lidar data in the 3DEP project covers the vast majority of the United States and several of its territories. Coverage is becoming more comprehensive over time. We have added 3DEP as one of our options when you import map elevation information from the web.

When creating a surface-water model, you are looking for the USGS 3DEP Bare Earth DEM (North America) option from the web.

Example of the 3DEP data

To access 3DEP data in SMS, do the following:

  1. Click File | Import from Web… to open the Virtual Earth Map Location.
  2. Make your location selection here (United States and some territories only)
  3. You may have to set your Display Projection settings
  4. When you reach the Data Service Options dialog box, scroll right until you see an option for USGS 3DEP Bare Earth DEM (North America).
  5. You then save your image to the appropriate location on your computer, after you set or accept the default raster cell size.

Once you have saved your image, it will show up in the Project Explorer window under GIS Data. When saving, it will add the " _elevs.tif" extension to the name you chose. The elevation data can then be applied to your model in the usual way.

Head on over to SMS and see how 3DEP data can help your surface-water modeling.

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Making Use of Recent Files in SMS

Jumping between multiple projects can be commonplace in most organizations. For this reason, the Surface-water Modeling System (SMS) includes a way to see your most recent projects. This feature makes it easier to jump between projects.

When starting SMS, you can see your recent projects by going to the File menu. Towards the bottom of the File menu, you will see the five most recent projects. Selecting any of these projects will load them into SMS.

Only the five most recent projects are listed in the File menu, but SMS provides a way to access more of your recent projects. Clicking the More… command under the recent files in the File menu will bring up the Recent Files dialog. The Recent Files dialog contains a list of recent projects. This list will go back to when the major version of the software was installed.

Example of the Recent Files dialog

The Recent Files dialog allows you to search for past projects using the Search field at the top of the dialog. This can be immensely helpful when trying to find a project that has been neglected for a while.

Also helpful is a feature that lets you open the location of the project files. You can right-click on any project and select the Open Containing Folder command to bring up the folder containing the project files in the File Explorer window. This can help you locate files you haven’t been working with in a while and may have forgotten the location.

There are some caveats to this feature. If the project files have been moved, the project will still appear in the list of recent files but SMS will not be capable of importing the file because it is being directed to the wrong location. This is also true if a folder in the directory is renamed.

The Recent Files dialog provides a great tool to help you manage your projects in SMS. Head over to SMS and see what projects you have been working on recently!

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Using Top Elevation Data for Starting Head Values for MODLOW 6

The Ground-water Modeling System (GMS) includes multiple methods of setting the starting heads in the Initial Conditions (IC) package for MODFLOW 6. Starting with GMS 10.8, you can use the top elevation data already entered in the Discretization by Vertices package (DISV) for your starting head values without any extra steps.

When you open the Initial Conditions (IC) dialog, it shows several options for setting the starting heads. For simple models you can set a constant value for starting heads across the entire grid. But for more complex models, you'll want values to better represent the test area. This often means you have to either manually enter, copy and paste, or import from another data file.

However, doing this sometimes involves duplicated work you might have already completed in the DISV package. To eliminate this inefficiency, GMS 10.8 has added a new method that allows you to use the DISV top elevation data as your starting head values. This can be done using the following steps:

  1. Open the Initial Conditions (IC) dialog.
  2. Check on the box that says "Set starting heads equal to cell top elevations."
Starting head equal to cell top elevation option

Turning on this option will match the starting heads to the elevation data already imported or entered in the DISV package and grays out all other parts of the dialog.

Using this option, the top elevation data will be used as the starting head values during the MODFLOW 6 simulation run. Setting the starting heads equal to the top elevations in GMS offers some benefits:

  • It provides an additional option for inputting the starting heads data.
  • It can save you time by using data already in the model.

As always, it is best to review the data before running the simulation and after running the simulation to verify that the values were incorporated correctly.

Now head over to GMS 10.8 and check out using your top elevation data as your starting heading values in your MODFLOW 6 projects today!

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Managing File Paths in WMS

When working in the Watershed Modeling System (WMS) the software refers to multiple applications and files in order to operate correctly. The default settings for accessing these files should generally be followed. However, there are times when these file paths need to be altered by you or the paths get changed unintentionally. This post will go over some of the important file paths to pay attention to in WMS.

Typically, WMS will be installed on your C drive or whichever drive you specify on your local machine. When WMS is installed, it will also install multiple other applications that it uses. These are most often the numerical models that WMS uses along with some drivers. WMS will keep everything contained to where it can find these applications.

However, to give you more flexibility, WMS allows you to change the location of these applications. Most path locations can be changed in the Preferences dialog. The Files tab of the Preferences dialog contains the file paths for the numerical models and other applications. The file paths can be changed here to direct to a different location. This can be useful when you are needing to use a different version of a model executable other than the one that comes installed with your version of WMS.

File paths set in WMS

The Preferences dialog also allows you to change the file path for the Temp directory. This is done on the General tab.

It should be noted that WMS retains these file paths once they have been set. Therefore, when you are moving files around, pay attention that WMS will not automatically update to the new location. When a model executable gets moved to another directory, you will need to manually update the file path in WMS in order to avoid potential errors.

The Files tab of the Preferences dialog is also useful for locating specific model executables and files that you suspect may need to be updated. This can help you troubleshoot model executable issues that occur during a model run.

Now that you know more about how WMS manages file paths, make use of them in your WMS projects today!

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Taking Advantage of the SRH-2D Channel Calculator

The Surface-water Modeling System (SMS) provides a useful tool that generates an estimated water surface elevation on an "Exit-H" boundary condition in an SRH-2D model. The Channel Calculator in SMS makes it easier to calculate water surface elevation values. It also gives you greater control of over the parameters

When building an SRH-2D model, the exit boundary will need to be defined. A constant elevation is often used, but this can not be sufficient in many cases. The Exit-H boundary condition is a stage type exit boundary where water surface elevation may be given as a constant number or as a stage-discharge or rating curve. The Channel Calculator is used to compute and assign a normal or critical water surface elevation for the outflow boundary condition. It also gives you greater control over the parameters used to determine the outflow conditions.

Example of the Channel Calculator in SMS

The Channel Calculator is accessed through the SRH2D Assign BC dialog. The Populate using Channel Calculator button appears at the bottom of the dialog when "Exit-H (subcritical outflow)" is selected as the BC Type and the Water Surface Elevation option has been determined.

The Channel Calculator specifies a composite roughness value, slope, and flow. SMS extracts a ground elevation cross section from a specified underlying elevation data source (mesh) that is used to compute the area and wetted perimeter. The calculator can make use of different types of elevation data sources which include DEMs, meshes, and scatter sets. Roughness and slope values will be required for the final calculation. Other options, such as the WSE offset, are optional and should only be used when necessary for your project.

The Channel Calculator will display a preview of the exit area cross section with normal and critical depth. When the Channel Calculator will save the values entered when exited. The values in the calculator can be changed later if needed.

The Channel Calculator in SMS gives you a useful tool for determining exit water-surface values for your SRH-2D projects. Try using it in SMS today!

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Utilizing MODFLOW Symbols Display Options

The Groundwater Modeling System (GMS) has many different options for customizing the display of your project. One display feature created for MODFLOW in GMS is the ability to use symbols to represent the properties of individual cells. This can be quite useful especially for more complicated MODFLOW models. You can use the MODFLOW symbols in the Display Options dialog to represent things like rivers, lakes, wells, drains, and more.

Example of MODFLOW symbols in GMS

You can find the MODFLOW display options as their own tab by selecting the corresponding grid from the list on the left side of the Display Options dialog. The MODFLOW symbols all have a default shape, size, and color. The shape, size, and color of the symbols can all be customized by clicking the button to the left of the checkbox. The ability to customize the MODFLOW symbols is a useful feature for everyone, but especially our users who are visually impaired or color blind. For the best results, the symbols should be set to something different enough from each other that it is easy to tell which is which at a glance.

If you use the MODFLOW symbols in your project, you should consider turning on the display symbol legend. The legend shows a list in the corner of the Graphics Window of all of the MODFLOW cell properties contained within the current project, making it easier to keep track of what everything means. Only symbols that exist in the layer being viewed will appear in the legend.

There are a few additional symbol display options for MODFLOW on the Map Data section of the Display Options dialog. A list of the symbols appears when MODFLOW is selected from the Coverage dropdown. These symbols are specific to properties on the coverages in your project, and they can be customized in the same way as the symbols under the MODFLOW tab of the grid in the Display Options dialog.

Open GMS and use the MODFLOW symbols in the display options to help you keep track of the properties of your MODFLOW project today!

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Moving Data to Other Geometries

After you have created a model in the Surface-water Modeling System (SMS), it is not uncommon to need to move your vector data or solution datasets from one geometry to another. It could be that your model ran using a 2D mesh and now you want to move the vector data to an unstructured grid for use in another simulation. SMS gives you the ability to accurately move vector data from one geometry to another which can significantly enhance the precision of your modeling efforts.

The Interpolate to UGrid tool is a powerful feature designed to streamline this process of moving datasets from one geometry to another. The Interpolate to UGrid tool is located in the Toolbox with the suite of dataset tools.

Example of the Interpolate to UGrid Tool in SMS

The Interpolate to UGrid tool facilitates the interpolation of a dataset associated with one geometry to another within the same project. While it primarily is meant to work with unstructured grids (UGrids), it can be used with other geometries such as 2D meshes or Cartesian grids. The tool will accept any dataset on the geometry, including vector and elevation sets.

The tool will follow an interpolation process to assign values on nodes or cells from one geometry to the next. Because of this, it is important to review the dataset after it has been moved, to verify that it transferred as expected.

The Interpolate to UGrid tool gives you several features that let you control the process of moving data from one geometry to another. These include:

  • Versatile Interpolation Methods: Choose the interpolation method that best suits your data and modeling objectives to achieve optimal results.
  • Customizable Interpolation Dimension: Tailor the interpolation process to match the dimensions of your target grid, whether it's 2D or 3D.
  • Truncation Options: Control the range of interpolated values with flexible truncation options. Whether you want to preserve the original data range or define custom minimum and maximum values, this tool provides the flexibility you need to fine-tune your results.
  • Extrapolation Capabilities: Handle extrapolation scenarios with ease, choosing from various extrapolation options to extend your dataset beyond the convex hull of the scatter point set.

Whether you're working with unstructured grids, 2D meshes, or other geometric entities, this tool provides the functionality and flexibility you need to enhance the accuracy of your modeling efforts. Make use of the Interpolate to UGrid tool in your SMS projects today!

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New Import and Export Curvilinear Grid Tools

There are two new tools in the Surface-water Modeling System 13.3 toolbox. If you work with curvilinear grids, then you’ll be pleased to know that there are now tools to import and export curvilinear grids. Both of these tools can be found in the Unstructured Grids folder in the toolbox.

Curvilinear grids are comprised of nodes organized into cells, which define the computational domain of a numerical model. Apart from defining the domain, these grids can also hold extra data like material properties for elements and boundary conditions for nodes. Curvilinear grids must be made up of only quadrilateral elements. This means that if you're creating a grid in SMS, you should make sure you're using the patch method for mesh generation.

Example of the Curvilinear Grid Tools in SMS

There are two file types that are supported for importing or exporting a curvilinear grid: CH3D (also referred to as GSMB) or EFDC (also referred to as LTFATE). Both file types include a cell i-coordinate and a cell j-coordinate dataset option. The EFDC file format includes additional input parameters for a depth dataset, Z roughness dataset, vegetation type dataset, and wind shelter dataset.

The Export Curvilinear Grid tool generates a curvilinear grid file (or files) for a curvilinear compatible mesh, scatter set, or UGrid within SMS. It can utilize user-provided I, J index datasets if available, and offers the capability to calculate I, J data indices. When computing these indices, the orientation of the initial cell on the surface determines the orientation of the grid's I, J axes.

You can use the Import Curvilinear Grid tool to import a pre-existing curvilinear (boundary fitted) grid into SMS as a UGrid object. This process simultaneously generates cell-based datasets that delineate the I, J indices for each cell within the UGrid. The exact format chosen and the nature of the data file(s) selected influence this import procedure.

Head over to SMS and give these new curvilinear grid tools a try!

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Defining Constant Concentration for Multiple Species in MT3DMS

Are you struggling to define separate constant concentrations for different chemicals in your MT3DMS model areas? MT3DMS is an invaluable tool for groundwater modeling, but like any software, it has its limitations. The Groundwater Modeling System (GMS) incorporates MT3DMS into its interface, which includes both the benefits and limitations of MT3DMS. The inability of MT3DMS to define separate constant concentrations for different chemicals in the same area can be a hindrance for modelers aiming for precision and accuracy in their simulations. So what should you do if your MT3DMS model requires defining constant concentration for two or more chemicals in separate areas?

There's a workaround provided by the MT3DMS developers for defining multispecies simulations. By using negative values in the table for species that need to be left undefined, you can effectively overcome this constraint and tailor your model to your specific needs. In GMS, this value is entered on the Source/Sink Mixing Package dialog for MT3DMS.

Example of the Constant Concentration Settings for MT3DMS

Note that it may seem as though a value of zero would have the same result when defining concentration. However, this is not the case. Entering a value of zero will be recognized as the same as entering a positive value. Therefore, it is important to enter a negative value for species that need to be left undefined when working with a multispecies simulation.

When running MT3DMS, cells that have negative values entered for a species will not have constant concentration for that species applied to that cell. Concentration, constant or varying, will be applied to all cells where the value is positive. As always, it is important to review the entered species values before running the model to ensure accuracy.

Now with more understanding of how to work with constant concentration values for multiple species in MT3DMS, see if you can use it in your GMS project today!

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Streamlining Watershed Analysis with AGWA

If you work with GSSHA, then you'll definitely want to check out the Automated GSSHA Watershed Analysis, or AGWA, app. AGWA is an online web application for managing proposed changes to watershed models. The app is powered by GSSHA--a hydrologic model developed by the U.S. Army Corps of Engineers.

Example of the AGWA Workflow

AGWA is web-based and therefore can be used from anywhere as long as you have an internet connection and a web browser. It includes simple step-by-step workflows to help you break down a more complex watershed analysis. These workflows can be applied to any number of GSSHA projects. The current workflows include:

  • Detention Basin Analysis
  • Culvert Resize Analysis
  • Find Discharge Tool
  • Land Use Change Analysis

AGWA uses the Tethys platform for managing accounts and access to projects. The GSSHA Models page in AGWA shows a list of all the GSSHA projects that are available for your account. The list includes the project name, project creator, description, and date of creation for each project. You can also view details about the model or the model map from the GSSHA Models page.

Clicking the launch button next to a GSSHA project on the GSSHA Models page will take you to the Model Summary page, which includes two tabs: the Summary tab and the Workflows tab. The Summary tab shows a summary of the GSSHA model including the name and description, map preview, creation date, and a list of scenarios. The Workflows tab shows all workflows that have been created or started, and is where you can create a new workflow.

All completed AGWA workflows have options to view the output data as plots. You can also download the flow and time series data as a CSV file so that you can use the results of your finished workflow outside of AGWA.

Check out AGWA, the app that lets you use GSSHA from anywhere! Follow this link to see a more complete list of the components of AGWA.

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