Aquaveo & Water Resources Engineering News

Parameter estimation using PEST can assist in data interpretation, model calibration, and predictive analysis. PEST can do a lot for your project.

Because PEST offers so much, it can be a little overwhelming to use at first. We provide tutorials and articles on our wiki to help guide you in using PEST with GMS.

In addition to the resources available in the tutorials and wiki, this post covers some useful tips that have helped some of our users.

General PEST Tips

Here are some general tips for troubleshooting PEST in GMS:

• Verify that the parameter key values have been successfully initialized under MODFLOW | Parameters. The key values should match the parameters names. For example, if the key value for hydraulic conductivity is “-30”, the parameter name should be “HK_30”. No key value should be used twice, even across different packages. To continue the example, if you have an “HK_30”, there should not be a “RCH_30”.
• Key values are needed for both zones and pilot points.
• Key values are expected to be negative integers. Non-integers will not be automatically recognized as key values.
• If the key value is not a negative integer, or is a parameter from the WEL package, they will have to be manually added. If you’re missing a value, check that it initialized in the first place.
• Parameters included in the run will be written to the *.param file. Once PEST runs, the optimal values are written to the *.par file.
• If the iterations are giving identical values for the same parameter, check if the value is either the minimum or the maximum of the range assigned to the parameter, then evaluate if that range needs adjusting.
• Adjusting the starting values or the PEST options may help.

Pilot Point Tips

When using PEST and pilot points, consider the following:

• Follow the recommended guidelines found here.
• You can get a quick 2D Scatter set to use for pilot points with the MODFLOW Layers → 2D Scatter Points tool. This is particularly useful for areal parameters, such as HK or RCH.
• If you’re running Null Space Monte Carlo, you must use pilot points and your interpolation method must be set to kriging.
• If running with SVD-Assist, you can point to the Jacobian file so it doesn’t re-solve for every iteration.
• Depending on the parameter, pilot points often should not start with zero values. This especially applies to log transforms.

We hope these tips help and that your project are improved by using PEST with GMS.

SMS allows having multiple simulations for the same project with models such as SRH-2D, ADCIRC, and STWAVE. Furthermore, SMS 13.0 lets you run and manage multiple simulations running at the same time using the new Simulation Run Queue dialog.

The Simulation Run Queue is a modeless dialog, meaning you can continue using SMS while simulations are running. Once a model run has started for a simulation, you are free to start building a new simulation, even one using the existing components. Completed runs may be visualized in SMS while additional runs are still in process.

Functionality

The new Simulation Run Queue dialog functions a little differently from the previous Model Wrapper dialog. Some of the changes include:

• You must click Load Solution to load the desired simulation solution into the project. This does not happen automatically when you click Close as it did before.
• If you try to run a simulation already in the queue, you will be prompted to remove the simulation from the run queue before it can be run again.
• If changing an active simulation’s settings, renaming the active simulation, or taking any action that affects a simulation currently in the queue, you will be asked to remove the simulation from the queue prior to making the changes.

Viewing Plots

With the Simulation Run Queue, diagnostic information—such as monitoring plots—can be displayed during model runs. By turn Monitoring Data off or on, you can watch command line results and residual plots.

Options also exist for changing which plots are displayed in the run queue. Selecting a simulation causes the Plot Options button to appear. In the Plot Options dialog, you can choose which plots to view. You can view Residuals, Monitor Points, and Monitor Lines, and change the options associated with each of these.

Now that you know a little more about the Simulation Run Queue dialog in SMS 13.0, try it out today!

Looking for a quick way to delineate a floodplain in your area? WMS provides a way to delineate a floodplain and create a flood impact map quickly, using many different types of data. This blog post will cover how to delineate a floodplain using scatter point data.

Start by opening your scatter point data:

1. Use the Flood | Read Stage File menu command to import your scatter point dataset. This is the recommended method for importing a scatter point set for using in delineating a floodplain.

Delineating the Floodplain

With the scatter point set imported, now delineate the floodplain.

1. Select Flood | Delineate menu command.
2. In the Floodplain Delineation dialog, choose the scatter point set you would like to model from the Select stage scatter point set drop-down menu.
3. Select the specific dataset you would like to delineate from the Select stage data set drop-down menu.
4. Set options for the Search radius, Flow path, and/or Quadrants depending on your individual model.
5. When done with the Floodplain Delineation dialog, the delineation process will begin for the set of water surface elevations selected.

In order to create a flood impact map, it will be necessary to have at least two different delineations using varying datasets. If you wish to go on to create a flood impact map, repeat steps 1-5 with a different dataset to obtain a new floodplain delineation.

Creating a Flood Impact Map

WMS can use two separate floodplain delineations to generate a flood impact coverage. A flood impact coverage shows the difference between two flood depth or water level sets. The differences are divided into ranges or classes. Using the floodplains delineated in the previous steps, we’ll create a flood impact map. This can be used to compare how an area will react to a proposed levee for example.

1. Select Flood | Conversion | Flood → Impact Map menu command.
2. Choose the Original dataset based off your previous delineations.
3. Choose your Modified dataset based off your previous delineations as well.
4. Set the Increase and Decrease sections as desired.

Now that the flood impact map is created, you can use the Select Feature Polygon tool to double click on any of the polygons in the map. This will show you the Flood Extent Attributes dialog, which displays info such as the amount of change between the compared datasets as well as the impact class ID and name.

So this a brief overview of floodplain delineation from a scatter point file using WMS. Try it out in WMS today!

In 2018, USGS released MODFLOW 6. This version of MODFLOW uses object-oriented programming to provide support for multiple models within the same simulation. Like many of you, we at Aquaveo were excited to see this new development and started on working on ways for GMS to interface with this new version of MODFLOW.

Did you know that with GMS 10.4 you can export your MODFLOW project for use with MODFLOW 6? This allows you to convert your older or current GMS projects for use with MODFLOW 6. This is just one of the new features in GMS 10.4.

Support has also been added to run MODFLOW 6 from GMS and read the head and flow outputs which may be contoured.

The general workflow process for saving, running, and importing the MODFLOW 6 files is as follows:

1. After building your MODFLOW model, open the MODFLOW Global/Basic Package dialog.

2. In the dialog, turn on the Save MODFLOW 6 copy option under the MODFLOW Version section.
3. Save your project.
4. Open MODFLOW | Advanced | Run MODFLOW Dialog... to run the MODFLOW 6 files.
5. Use the Custom MODFLOW option to point to the mf6.exe executable in program files (e.g., C:\Program Files\GMS 10.4 64-bit\models\mf6\mf6.exe).
6. Browse to and select the NAM file out of the *_MODFLOW_mf6 folder that will have saved in the same directory as your GMS project. This is not the default, so you will need to browse for it at least the first time.
7. Run MODFLOW.
8. Use MODFLOW | Read Solution to select the MFN file out of the *_MODFLOW_mf6 folder.

The exported files can also be used directly in MODFLOW 6.

In the future, we plan to add more MODFLOW 6 functionality to GMS including a full interface. For now, get ready by converting your projects to MODFLOW 6 using GMS 10.4.