Aquaveo & Water Resources Engineering News

Trimming DEMs in WMS

Have you imported a DEM into WMS but wanted to trim it down to use only a part of the original data? WMS has tools designed to help you trim DEMs that you have imported into WMS, so you can use only the part of the data that's relevant to your model. In this article, we explore the ways that this can be done in WMS.

Trimming a DEM can help eliminate extra data that is not necessary for your project. Having a DEM that is too large or contains data that is irrelevant to your project can cause your project to operate slower and in some cases can skew the results of your project.

One option for trimming a DEM is when it's part of the GIS Data Module as a raster. To do this, draw a feature object polygon in a map coverage then select it. With the polygon selected, you can right-click on the raster and select the Convert To | Trimmed Raster command. This trims the raster along the border of the polygon. The trimmed raster can be converted, if desired, to a DEM that will show up under the Terrain Data folder.

Of course, there are also tools for trimming files that are already in the Terrain Data Module as DEMs. These tools can be accessed either through the DEM menu when in the Terrain Data Module or through the right-click menu for a DEM item in the Project Explorer. In both places, the tools are found in the Trim submenu.

There are two ways to trim DEMs in the Terrain Data Module: by elevation and by polygon.

When trimming a DEM by elevation, WMS brings up a dialog that lets you specify the maximum elevation that you want the DEM trimmed to. The newly created DEM will have only elevations up to the maximum elevation set in this dialog. The contours will likely change to represent the new range of values in the trimmed DEM.

Example of trimming a DEM using a polygon in WMS

When trimming a DEM using a polygon, the program turns the mouse into a tool to click out the polygon in the Graphics Window. To finish the polygon, double-click where the last point is desired. Once the polygon is complete, the trimmed DEM is automatically created.

Note that a DEM created this way is still a rectangle. This is part of the definition of a DEM. However, only the points inside the drawn polygon will be active, so the displayed contours will end at the borders of the polygon you drew. The points that were outside the drawn polygon, which make up the rest of the bounding rectangle, are set to NODATA.

Take advantage of DEM trimming tools in WMS today!

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The Create Bridge Footprint Tool in SMS 13.2

Do you have an SMS project with a bridge represented in the mesh? SMS 13.2 offers a new tool called Create Bridge Footprint that assists in representing bridge footprints in SRH-2D simulations.

Since the real-life effects of bridges can be complex, creating a mesh to represent them is often challenging. Modeling piers and abutments using older methods in SMS requires many polygons in Mesh Generation coverages. Now, the Create Bridge Footprint tool provides an alternative approach to creating an unstructured mesh under and around a bridge structure. Note that this tool replaces the functionality made available in the Bridge-Piers coverage, which you might have been using in SMS 13.1. However, many of the same settings are incorporated in this tool as well.

The Create Bridge Footprint tool, located in the Toolbox dialog, produces a coverage and mesh that represent the bridge footprint. These features can then be used to create a mesh that incorporates the bridge footprint into the larger mesh for the model.

Example of the Create Bridge Footprint Tool

The set up for the tool includes creating a new coverage with arcs that define the new bridge:

  • The first arc should define the centerline of the bridge. It is the longest arc.
  • Other arcs, drawn across the first arc, define where the piers and abutments are located. The length of the piers is set in the tool parameters before the tool is run, so the length of these arcs is unimportant.

When drawing the feature arcs to represent the bridge for the tool, there are some important things to keep in mind. One of them is that the bridge feature arcs must be the only feature objects in the coverage. Any other objects will confuse the Create Bridge Footprint tool.

It's also important to make sure that all of the shorter arcs cross the centerline, but none of them should intersect the centerline. In this case, intersecting is different from crossing in that it creates a node on both arcs. This splits the centerline arc, making it impossible for the tool to interpret the intended meaning of the arcs.

After setting up the arcs, there are some parameters to set in the tool to complete the model of the bridge. Then the tool can be run and the resulting mesh and coverage reviewed, and you're one step closer to completing your model.

Try the Create Bridge Footprint tool in SMS 13.2 today!

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Using Map from Coverage in GMS

If you are using MODFLOW 6 in GMS, you may notice that it uses a different workflow than other versions of MODFLOW in GMS. These changes were made to improve flexibility and performance for groundwater modeling in GMS. One difference is the process of mapping data from the conceptual model to the MODFLOW simulation. In all versions of MODFLOW in GMS, mapping involves taking data input in the conceptual model and "mapping" that data to the grid or mesh being used by the MODFLOW simulation. With every other version of MODFLOW, this is accomplished using the Map to MODFLOW command. However, in MODFLOW 6, mapping is accomplished using the Map from Coverage command.

Now, why this change? It mostly has to do with differences in how GMS handles these different kinds of MODFLOW. A GMS project can only hold one older MODFLOW simulation, but GMS was improved to allow multiple MODFLOW 6 simulations in a project. For handling multiple models and simulations, the Map to MODFLOW command is insufficient. There might be multiple simulations in your project, and you might not want the coverage or conceptual model you are pulling data from to map to all of these MODFLOW 6 simulations.

So how does the new command work? For a MODFLOW 6 package in GMS, do the following:

  1. Right-click on the simulation package and select the Map from Coverage command.
  2. Select a coverage for GMS to map over the package.
Example of the Map from Coverage coverage

GMS will then map the data from the coverage into the MODFLOW 6 package. It's important to note that only some of the MODFLOW 6 packages can be mapped from coverages. This means some packages must be manually set up in their package dialog. This new workflow can have some important effects on how you build your MODFLOW 6 simulation. In MODFLOW 6 it’s especially important that you map over the correct coverage. Since the data isn’t generically mapped over to MODFLOW, it’s especially necessary to know which coverage will be used to define each MODFLOW 6 package.

Try out the Map from Coverage process for MODFLOW 6 in GMS today!

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Tips for Modeling 3D Bridges in SMS 13.2

Do you have an SMS 13.2 project that could benefit from using a 3D bridge? Today's blog post covers some things to consider as you model 3D bridges in SMS.

First, it’s important to know that SMS identifies the arc drawn first as the upstream side of the bridge. So the order in which the arcs are drawn affects the final bridge model. However, before the bridge is fully created, it’s possible to switch which side of the bridge is upstream using the Swap Arcs command in the Bridge dialog. Checking that the arcs are assigned to the correct side of the bridge can prevent errors later in the model.

When the bridge is created, it can be imported automatically into the model. So the bridge file is exported from SMS, but then SMS imports it automatically. To import the bridge automatically, select the Add 3D Bridge UGrid to SMS on OK option in the Bridge dialog. This eliminates the need to search for it then import it.

Example of 3D Bridge Modeling in SMS

However, if the 3D bridge file is moved, it's important to keep in mind that two files were created by modeling the bridge: an XMUGRID file and a PRJ file that contains the projection for the UGrid. These files should be kept together.

Finally, modeling piers is sometimes an important part of modeling a 3D bridge. The top and underside of a 3D bridge are defined using XY Series Editors accessible in the Bridge dialog. When defining any elevation changes in the 3D bridge, the distance (x) values cannot be identical to each other. This means it’s impossible to create a precisely vertical slope using this tool. To approximate a vertical slope, first input distance values that are very close to each other (e.g. 79 and 80). Then, pair them with elevation values that reflect the change in elevation.

Please keep in mind that piers used for an SRH-2D pressure flow model should not be modeled using the 3D bridge tool. Piers in that kind of model should be modeled using voids in the mesh.

Use these tips in creating a 3D bridge in SMS 13.2 today!

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How to Export Contour Lines as Shapefiles in SMS

Have you been wanting to export the contour lines in your SMS project as a shapefile so they can be opened in a different application? SMS allows exporting contour lines as a shapefile. This post will explain how to export contour lines as shapefiles.

Saving your contours as a shapefile requires your project to be set up correctly. Save the contours as a shapefile by doing the following:

  1. Make sure the contours you want to convert to a shapefile are set to Linear in the Display Options. To do so, open Display Options and click on the page for the geometry that has the contoured dataset loaded (e.g. mesh, UGrid, etc.). First, make sure that contours are turned on. Then, click on the Contours tab. In the Contour Method in the top left, make certain the first dropdown is set to "Linear".
  2. Make sure the desired dataset is active in SMS. This can be done by clicking on the dataset in the Project Explorer.
  3. In the File menu, select the Save As command. In the Save as type drop-down menu, select Shapes Files (*.shp). Then navigate to the desired directory. Make sure it's somewhere you will know how to find it. Then click Save.
  4. Once you’ve clicked Save, a dialog opens that gives you options for converting project information to a shapefile. Select one of the contour options. The “Mesh Contours → Arc Shapefile” option is usually best.
  5. Now open your shapefile in the appropriate GIS software. The contour lines will appear as arc lines.
Example of Exporting a Shapefile from SMS

If you encounter issues with the shapefile, start by 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. Try using the Uncheck All command in the Project Explorer and then checking only the desired geometry. This could allow you to more clearly see the contours as they will appear in the shapefile. You might also consider using the display options to turn off the geometry elements. This would also allow for clearer visualization of the contours. Once you can see the contour lines clearly, use the display options to adjust the contour lines if needed. Finally, there may be some differences between how SMS displays a shapefile and how other GIS applications display the shapefile. Opening the shapefile in SMS can help you determine if this is the case.

Be aware that selecting the Mesh Contours → Polygon Shapefile option when exporting the shapefile causes SMS to create a shapefile with only polygons. This might not accurately reflect the linear contours displayed in SMS since some of them might be only line segments.

Try out exporting contour lines as shapefiles in SMS today!

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Risk Analysis for Well Groups

In your groundwater model, do you need a way to capture multiple wells for risk analysis? For example, your project might have multiple pumping wells and you would like to see the probabilistic composite capture zone for all wells in the wellfield. GMS provides a way to access the Risk Analysis dialog for refining stochastic modeling results.

Example of the Risk Analysis Wizard in GMS
  1. First open your project in GMS, making sure to select the Plan View and 3D grid module, it will be more difficult to select wells otherwise.
  2. Using the Select Cells tool, drag a box around the entire grid to select all cells in the grid.
  3. Open the 3D Grid Cell Properties dialog and change the value for the MODPATH zone code to a number of your choice.
  4. Select the coverage of the well to make it active. Using the Select Points/Nodes tool, drag a box around the entire project to select all wells in the coverage.
  5. Select Intersecting Objects to open the Select Objects of Type dialog.
  6. Select 3D grid cells from the list and close the dialog. This will select all 3D grid cells that have a well in them.
  7. Open the 3D Grid Cell Properties dialog.
  8. Change the value for the MODPATH zone code to a different number than the one that was used before, close the dialog and save changes. From here, the probabilistic capture zone analysis should be able to run with the well groups setting turned on.

Please note that particles need to leave their original zone to be mapped on the risk analysis results. That is why nothing will show up when all cells were assigned to the same zone. The recommended solution is to change the zone code of just the cells with a well so that as many particles as possible can leave the assigned area.

GMS allows you to be as general or specific as you need when selecting wells for risk analysis. Try out using risk analysis for well groups using GMS today!

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Hardware Guidance for XMS

Are you wondering about what computer system to use with GMS, SMS, or WMS (collectively known as XMS) to get the best performance? The hardware you select will certainly make a difference in how XMS performs. This blog post intends to give some guidance for selecting hardware for use with XMS.

What hardware is required will depend very much on which models you choose to run and how large the projects are. Many lower power systems will technically run the software, but the interface may be slow and the simulation may take a very long time to run. In the end, the computer components you choose will depend on what you intend to do and the budget you have to work with. To help in the decision-making process, we have included some recommendations and explanations on how different components will affect the performance of the software. Look at your budget and see what is reasonable; it is recommended that you get the best you can afford.

Example of System Hardware for XMS

For some basic system requirements, you can check out this page on our wiki. Note that these requirements will change over time as technology evolves. The system requirements will change as future advancements are implemented into XMS.

The CPU is the component that will make the most difference in how fast the software runs. When comparing CPUs, we recommend looking at single-core rather than multi-core performance. The reason for this is that many of the models in our software do not take full advantage of multiple CPU cores at the same time. That being said, we do recommend that the CPU have at least 4 cores to give everything the power that it needs. Remember that it should be the best that you can afford

For RAM, 16 GB is usually sufficient, but some very large projects have required more. You may also want to get more RAM if you plan to have more than one project open at the same time. Our office computers have 16-32 GB of RAM, depending on the machine.

For a graphics card, we recommend getting a current low to mid-range dedicated card designed for gaming. Large projects can require multiple gigabytes of VRAM, but our cards with 4GB have yet to run into issues needing more. The speed of the GPU will particularly affect how smoothly the pan, zoom, and rotate tools work.

For storage, we usually recommend having an SSD with plenty of space. Projects can end up taking quite a bit of disk space, especially if the Save As function is used frequently. Having faster storage will reduce project load times and how long it takes to save a project. Note that storing projects on external/network drives have been known to cause issues, so we recommend storing any project files you plan to open on a local drive. Again, it is recommended that you get the best you can afford.

Having the right hardware will increase the usefulness of XMS for your modeling projects. Check out the XMS software applications today!

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Specifying Arc Lengths in SMS 13.2

Imagine yourself trying to get an arc in an SMS map coverage just the right length. You keep on moving around the endpoint, but that often moves its azimuth as well. What’s more, measuring the arc would require using the Measure tool, and maybe that’s not precise enough for you. Fortunately, the most recent release of SMS has a solution. Today, we take a closer look at the Specify Arc Length tool, a tool designed for helping you be detailed in creating arcs. This tool, which was released as part of the beta of SMS 13.2, enables you to extend or shorten an arc by a specified length.

Let’s say that you have drawn an arc, and it’s pretty close to what you wanted, but you would prefer it just a little longer. You could manually adjust it, but using the Specify Arc Length tool, you can make it exactly the length you prefer.

Here’s how:

  1. In the Map module, select the Select Feature Arc tool.
  2. Select the arc you want to modify.
  3. Right-click and select the Specify Arc Length command.
  4. In the Specify Arc Length dialog, specify the desired arc length in the New Arc Length section.
Example of the Specify Arc Length in SMS

If the desired arc length is longer than arc’s current length, then the arc extends to match the entered length. If the desired arc length is shorter than the arc’s current length, then a new node is created to shorten the arc. Shortening an arc results in the creation of two arcs.

There are some important things to keep in mind when using this new tool.

First, the arc can only be adjusted relative to the arc direction, which is usually the direction the arc was drawn (e.g. right to left) when it was created. This means extending the arc moves the end node of the arc in a straight line in the arc direction until the whole arc is the desired length. Shortening the arc adds a node the specified distance along the arc in the arc direction. This can be seen in the image below. The beginning of the arc (usually the node drawn first) never moves as a result of the Specify Arc Length tool.

It’s also important to be aware of the arcs attached to the arc you’re modifying. If the arc is attached to another arc, then extending the arc also modifies the length of the arc it is attached to. Be sure that adjusting both arc lengths is desirable before using this tool.

Furthermore, when extending an arc with many segments, note that only the segment at the end of the arc gets extended. The final segment extends in a straight line as shown below until the arc is the specified length. The rest of the segments are left untouched.

This is just one of the many tools that SMS13.2 makes available to enhance your water modeling capabilities. Try out using the Specify Arc Length tool in SMS 13.2 today.

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Adding Multiple Screens to Well Points

Do you have multiple screens to add to your MNW2 wells? Adding multiple well screens can be an important part of modeling what a well situation looks like in real life. But you might be frustrated trying to figure out how to get multiple screens on your well points. Today, we detail how to add multiple screens on MNW2 wells.

While wells with singular screens can be imported using the GMS import wizard, adding more than one screen to a well necessitates a different workflow.

To add multiple screens, add them one at a time to each well:

Example of setting multiple well screens
  1. Create a coverage with MNW2 wells enabled.
  2. Use your TXT or CSV file to add the well points to your coverage through the import wizard.
  3. Once the points are in GMS, right-click on that coverage and choose Attribute Table.
  4. Make sure that your Show dropdown is set to "all", so that each well point is visible.
  5. If needed, uncheck the checkbox in the Use screen column.
  6. In the column labeled Boreline, click on the ... to open up the z screen table for one of your points.
  7. In that table, you can list (or copy/paste) all of the well screen values applicable to that well point.
  8. Repeat steps 5–7 for each well.

Since adding multiple screens is a manual task, staying organized is an important part of it. Consider keeping track of which wells you have already added screens to. You could keep track in a spreadsheet or in a notes application of your choice. This is especially important with a large number of wells because it is not obvious in the Attribute Table which wells already have screens assigned to them.

Again, adding multiple screens is specifically for MNW2 wells. So, if you have multiple screens to add to your wells, then you might consider changing them to MNW2 wells. This would allow the wells to accommodate adding multiple screens.

If you have a project needing multiple well screens, use GMS today!

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Rebuilding an SRH-2D Restart File

Have you ever needed to rebuild an SRH-2D restart file for a project you were working on? Perhaps you lost the restart file or maybe you made modifications to your mesh, so the restart file is no longer valid for the model you have. Regardless of the cause, rebuilding a restart file can be a vital step in completing the model you're working on.

To start rebuilding your restart file, see if you can do a dry run of your simulation:

Example of the SRH-2D Model Control Set to Use a Dry Run
  1. Right-click on the simulation in the Project Explorer and select Duplicate.
  2. This ensures that the original simulation is preserved if needed.
  3. In the newly-created simulation, right-click and select Model Control to open the Model Control dialog.
  4. In the dialog on the General tab, for the Initial Condition drop-down select "Dry".

Every run of SRH-2D creates restart files for the model. Initially, it creates a restart file for every time step as determined by the Output Frequency in the Model Control dialog. However, when the solution is loaded into SMS, the software only saves the restart file for the final time step. If a restart file for a different time step in the simulation is desired, then please complete the following before clicking Load Solution in the Simulation Run Queue dialog:

  1. Browse to where the project is saved.
  2. Double-click on the folder with the same name as the SMS project.
  3. Double-click on the SRH-2D folder.
  4. Double-click on the folder with the same name as the simulation run.
  5. This is where restart files were written for every time step. The file that ends in "_TSO.dat" is a text file with information about which restart files correspond to each time step. Open it in a program that can read plain text files to make sure that you select the restart file with the desired time step. The restart files end in "_RST" followed by the time step number (e.g. "Standard_Run_RST12.dat").
  6. Once you have determined the restart file you want to save, copy and paste it in a different folder on your hard drive.
  7. Then click Load Solution in SMS.

SMS loads the results into SMS and keeps only the restart file for the final time step. It's important to remember that changing anything in the mesh necessitates the creation of a new restart file. Restart files should only be used with a model that uses the exact same mesh as the simulation that generated the restart file. Using the restart file with a slightly modified mesh might yield inaccurate results.

SRH-2 with SMS provides powerful tools for surface-water modeling. Use SMS today!

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