Aquaveo & Water Resources Engineering News

Do you need to add soil data to your GSSHA model in WMS? Soil data is often needed in a rainfall/runoff GSSHA model so that infiltration can be considered in the model. WMS makes this easy by allowing soil data to be converted to an index map.

In order to include soil data in your GSSHA model, there are few steps to follow.

First, you will need a soil data map coverage. Once this coverage has been created you can add soil data directly to the map coverage. Often, you may have soil data located on a shapefile or other source. The soil data on the shapefile needs to be mapped over to the soil data coverage before creating the index map.

Second, the index map will be included with a 2D grid for the GSSHA model in WMS. Make certain you have created your 2D grid and initiated your GSSHA model.

Finally, convert the soil data coverage to be an index map in your GSSHA project. This is done by doing the following:

1. Use the GSSHA | Maps command.
2. In the GSSHA Maps dialog, set the soil data coverage to be used.
3. Click the Coverages to Index Map button.

Once you have converted your soil data to an index map, you can use it in your GSSHA model.

When converting soil data to an index map, we do have some tips to make it go smoother.

• When converting a shapefile to a soil data coverage, make certain that the soil data with the shapefile has been joined to the shapefile.
• After mapping a shapefile to a soil data coverage, make certain that the soil data mapped over.
• Check to see if soil covers the entire area of the 2D grid. A warning may appear if the soil data does not cover the area of the 2D grid.

Once your soil data have been successfully converted to an index map, it is ready to be used in your GSSHA model.

Try out using soil data with GSSHA in WMS today!

Are you needing to use multiple processors to run your MODFLOW or MODFLOW-USG model? Using multiple processors can speed up the model processing time. In order to use multiple processors for MODFLOW in GMS, the SAMG solver provides the means to do this.

The SAMG solver is developed by the Fraunhofer Institute for Algorithms and Scientific Computing (SCAI). It contains a library of subroutines for the highly efficient solution of large linear systems of equations with sparse matrices. SAMG has an advantage in being almost unconditionally numerically scalable. This means that the computational cost using SAMG depends linearly on the number of unknowns.

Before using the SAMG solver, check to see if you have it added to your license. Do this by going to the Register command in the Help menu. Look through the list of components to make certain the SAMG parallel interface / solver has been enabled.

The SAMG solver works with the LMG solver package in MODFLOW. The LMG solver needs to be selected to access the SAMG solver. The LMG solver links the MODFLOW project to the SAMG solver.

To activate the SAMG solver do the following:

1. Open the MODLOW Global/Basic Package dialog.
2. Then open the MODFLOW Packages dialog.
3. Turn on the LMG – Link-AMG option.
4. A warning may appear discussing the SAMG solver. This warning can be turned off if desired.
5. Once the LMG solver has been turned on, the Link-AMG (LMG) Package dialog can be accessed through the MODFLOW menu in order to set the solver parameters.

Using the SAMG solver is not ideal for all MODFLOW projects. It is generally meant for large linear problems and simulations which use several time steps. For the right project, SAMG can help significantly accelerate the model run time.

For MODFLOW-USG, the SAMG solver is used with the SMS Solver. You can select the SAMG solver in the SMS Solver options.

Contact Aquaveo's licensing team to see about using the SAMG solver with your GMS projects.

SMS contains several ways to work with datasets. Perhaps the most useful of these is the Dataset Toolbox. The Dataset Toolbox has several tools for generating new datasets. Among these are the temporal tools which allow adjusting the time steps for a transient dataset. The temporal tools include two options: Sample Time Steps and Merge Dataset.

The Sample Time Steps tool allows the creation of a dataset with a different number of time steps. The time steps can either be increased or decreased. To use the Sample Time Steps tool:

1. Open the Dataset Toolbox and select the Sample Time Steps tool.
2. Select the transient dataset you want to use.
3. Select the starting and end times.
4. Enter the time step frequency and units.
5. Give the new dataset a name and click Sample.

The other temporal tool is the Merge Dataset tool. This allows us to combine two transient datasets. To use this tool, the transient datasets being combined cannot have overlapping time steps. Most often, this tool is used to append multiple simulation runs together.

For example, if you completed an SRH-2D model run for one day, then created a new simulation for a second day (using a hot start file from the end of the first day simulation run), you could combine the results of the two simulation runs using the Merge Dataset tool.

To use the Merge Dataset tool:

1. Open the Dataset Toolbox and select the Merge Datasets tool.
2. Select the first dataset to use, then select the second dataset.
3. Enter a name for the combined dataset and click Compute.

When using the Merge Dataset tool, make certain that the first dataset selected has time steps that are earlier than the second dataset selected.

The temporal tools in the Dataset Toolbox provide a simple way to adjust transient datasets in your project. Try using these tools in SMS today!

Delineating an accurate basin is an important part of a watershed project. WMS provides a number of tools for delineating a watershed basin. The Hydrologic Modeling Wizard is often used to step through the entire process of delineating a basin.

However, it is possible to delineate a basin using data from outside of the Hydrologic Modeling Wizard. In particular, the Drainage module contains tools for delineating a basin using existing project data.

For example, if you have a shapefile with polygons that gives the general outline of the basin, that shapefile can be used to delineate the basin. To use the shapefile polygons to delineate the basin, do the following:

1. Import the shapefile into WMS. Verify the location is correct.
2. If you have not already done so, add a DEM for the area of interest to the project.
3. Generate the flow direction and accumulation, either by running TOPAZ/TauDEM or by importing it.
4. Map the shapefile polygon(s) into feature polygons in a drainage type coverage.
5. Place your outlet point(s) and digitize the streams. You can either manually draw the arcs, or load the streams from a shapefile. Be sure to verify that the arcs are set to Stream (not Generic) and that the directions are flowing from upstream to downstream (see "Stream Arrows" in the Drainage Display Options).
6. Select DEM | Polygon Basin IDs -> DEM in the Drainage module.
7. Select DEM | Compute Basin Data in the Drainage module.

Once you have a delineated basin, you can use the basin with the watershed modeling model of your choice. Be certain to review the basin to make certain it contains all of the area you need for your project.

WMS provides a large amount of flexibility in delineating a watershed basin in order to adapt to the needs of your project. Try out the different basin delineation tools in WMS today!