SMS

Discover the Map Activity Tools in SMS

By aquaveo on September 17, 2024

Aquaveo’s Surface-water Modeling System (SMS) comes equipped with various tools that streamline the water modeling process. In this collection, the Map Activity and Map Activity to UGrid features in the toolbox allow you to precisely define active and inactive areas of a grid or dataset. Some models and processes depend on being told which areas are active for which purpose these tools have been included.

The tools Map Activity and Map Activity to UGrid are located in the software Toolbox in the Datasets folder and Unstructured Grids folder, respectively. Both will create a new object based on the defined activity: either a new dataset or a new unstructured grid (UGrid).

The Map Activity tool has the ability to choose the activity dataset that will define the values for the new dataset using the Value dataset option, and the ability to choose the dataset that will define the activity for the new dataset using the Activity dataset option. Once you have selected the inputs, the only thing left to do is name the new activity dataset and run the tool. The tool outputs a new dataset that displays the custom inputs in the Graphics Window.

An important step when using the Map Activity to UGrid tool is establishing the proper activity coverage that defines the active and inactive areas of the unstructured grid. Ensure that you create an “Activity Classification” coverage with defined polygons in order to run the tool successfully. Additionally, assign polygons to the coverage to enable specificity when mapping activity. This tool has the ability to choose the geometry that will define the values for the new UGrid using the Input grid option, and the ability to select the coverage that will define the activity for the new UGrid using the Activity coverage option. After selecting the inputs, you name the new activity UGrid and run the tool. As a result, the tool populates a new UGrid that displays the given dataset inputs in the Graphics Window.

Now that you’ve been introduced to the activity tools in SMS 13.3, try using them in your surface-water models today!

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SMS

Tips for Pressure Zones with Overtopping in SRH-2D Models

By aquaveo on September 3, 2024

Does your SRH-2D project have a box culvert or pressure zone with overtopping that is proving to be a bit difficult to get correct?

Box culverts or pressure zones with overtopping are common features added to many SRH-2D models. Depending on how the pressure zone is created in your Surface-water Modeling System (SMS) project, this can be a tricky process for SRH-2D to handle. Here are some steps and tips for creating this feature successfully in SMS.

1 Use Quadrilateral Elements

Create quadrilateral elements between the boundaries of the pressure zone. Using quadrilateral elements tends to increase the stability and reliability of the SRH-2D model run. Quadrilateral elements can be created in one of two ways.

The first is to create the quadrilateral elements when creating the 2D mesh. Create a polygon for the area between and around the pressure zone. Assign this polygon with the Patch mesh type in the 2D Mesh Polygon Properties dialog.

The second method is to create the quadrilateral elements directly in the mesh using the Split/Merge tool and the Switch Element tool. This can be time-consuming, so it is only recommended for small adjustments.

2 Create Voids

Create voids in the mesh on either side of the pressure zone. There are two options for creating these voids, but one option seems to work better.

The first option, and the more stable one, is to create the voids on either side of the pressure zone when generating the mesh. Create the voids as polygons and assign them the None mesh type. It is generally best to make each void a quadrilateral polygon to imitate the thickness of a concrete wall or barrier.

The second option is to generate the mesh then use the Select Elements tool to select and delete the elements where the voids should be. Using this method requires renumbering the mesh nodes. There is a risk that you will not be able to delete all of the nodes related to the elements which can make your mesh unusable to SRH-2D.

3 Assign Boundary Conditions

Two arcs are needed to define the pressure zone. Each arc should be created on an SRH-2D boundary condition coverage. When creating the arcs, make certain all 2D mesh elements between the arcs are quadrilateral elements. Also, it is advisable to have at least one row of quadrilateral elements just past the downstream arc.

Once the arcs have been drawn, select both arcs and open the SRH-2D Linear BC dialog. Set both arcs to the Pressure type, making sure the correct arc ID is assigned to upstream versus downstream, and turn on the Overtopping option.

Both the boundary condition coverage and the 2D mesh can be added to your SRH-2D simulation to have a pressure zone with overtopping included in the results.

Try out adding a pressure zone in SMS today!

This post was originally published September 12, 2018.

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SMS

Build Watershed and Streams from Raster Data

By aquaveo on August 27, 2024

Delineating a watershed area into a usable model can be a daunting process. Two new tools in the Surface-water Modeling System (SMS) Toolbox make defining a watershed domain quick and easy. Introducing the Streams from Rasters and the Watershed from Rasters tools.

These two tools are found in the Coverages folder in the Toolbox.These two tools can extract data from an imported raster to automatically generate the feature objects for watershed streams and domains for your SMS model.

The first tool, Streams from Raster, will evaluate the raster elevation data, extract the direction of runoff, create connected arcs, and put it into a separate coverage for you. You’ll need a directional raster in order to run the tool.

The Streams from Raster tool will show the entire runoff flow based on elevation in the selected raster. If water starts here, then it will go in that direction until it ends up there in that stream bed. You can see and trace the most likely paths for water flow until it hits the lowest point possible for that flow path. This can help you plan where to place your stream arcs for your model.

A watershed domain created from raster data

The Watershed from Rasters tool creates a domain of the watershed area. This tool uses an amalgamation of several processes that operate in a particular order in the background as the tool runs. Several of these processes have been added to the Toolbox, including Streams from Raster, to run as separate tools, if desired. Once run, you will end up adding feature objects that define a domain to a coverage.

Then, the feature objects can be used to create a geometry (2D or 3D meshes or UGrids, etc.) of the watershed area. By using the Watershed from Raster tool, it enhances the speed at which a model can be created.

Head on over to SMS and try delineating a watershed with these new tools in your next model.

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SMS

2D Mesh Editing Versus Regeneration: Which is More Apt?

By aquaveo on August 6, 2024

If you need to make a change to a mesh, should you use the toold in the 2D Mesh module to edit, or instead regenerate the mesh? A 2D mesh consists of elements that define the computational domain of the numerical model. A numerical simulation requires a geometric definition of its domain– the mesh, available for use in SMS 13.3. Occasionally when constructing a mesh, a moment occurs where the mesh is insufficient for any reason.

In most cases the recommendation is to regenerate the mesh; as opposed to editing the mesh manually. The following list involves common circumstances where one may manually edit a mesh:

There is no mesh generator coverage present.
Deleting Outer Elements: Since the triangulation process creates elements (i.e. thin triangles) outside the mesh boundaries, deleting outer elements provides some refinement.
Merging Triangles/Element: Numeric solvers are more stable and accurate when quadrilateral elements are rectangular and triangular elements are equilateral.
Editing Individual Elements: After compound edits, a mesh could benefit from individual manipulation to increase stability. Swapping edges: Think of the two triangles as a quadrilateral, and the common edge between them is a diagonal of the quadrilateral. By swapping this common edge, it changes to be along the opposite diagonal of the quadrilateral. If this edge is clicked again, it returns back to its original state.
Turning a specific element into a void element.

You may make edits in the Mesh Generator coverage. Manual edits should be intentional and reserved for small sections of a mesh. Generally, manual edits of a mesh ought to be minimal.

In nearly all cases the recommendation is to regenerate the mesh; as opposed to editing the mesh manually. This is because any process that edits a mesh, causes the node and element ordering to become disorganized. Additionally, editing a mesh invalidates any solution files that have been previously saved. Manually editing a 2D mesh risks creating issues with the assigned elevation data or other datasets being used. As such, if there is a solution dataset attached to the mesh, the model simulation should be re-run.

A useful tip is reviewing your mesh before generating, using the preview tools that are available in a given dialog. Make adjustments to the arcs, vertices, and polygons on the mesh. Do not be afraid to add more arcs, vertices, or polygons if further refinement is needed.

If you want to generate a new mesh with the desired edits, you will need to create a mesh generator coverage. The following are examples of tools that can create a new mesh: