Aquaveo & Water Resources Engineering News

Using the Snap Preview Option

Having trouble with your boundary conditions or materials not aligning correctly with your mesh?

When a simulation runs in SMS, it takes all of the components—such as boundary conditions and materials—and aligns them with the 2D mesh or other geometry. When creating boundary conditions in the Map module for SRH-2D, ADCIRC, or other models that use simulation components, it can sometimes be difficult to know exactly where the boundary conditions will line up with the 2D mesh nodes.

To help with this, the boundary conditions map coverage contains a display option to see how the map arcs and mesh nodes will line up: the Snap Preview option.

To use the Snap Preview option, do the following:

  1. Make certain the project contains a 2D mesh and a boundary conditions coverage that have been linked to a model simulation
  2. Open the Display Options dialog
  3. On the Map tab of the dialog, turn on the Snap Preview option

The Snap Preview option can also be turned on or off by using the Shift+Q shortcut key.

When the Snap Preview option has been turned on, a dashed line will be displayed along the element edge to show where the boundary condition arcs will match up with the mesh nodes. This is helpful in identifying if the placement of the boundary condition arcs is correct. Incorrect placement of boundary condition arcs can cause errors in the model run.

Snap Preview Example

The Snap Preview option also works for other model coverages such as the SRH-2D materials coverage. This allows previewing how material assignments will match up with the mesh elements. Adjustments can then be made to the material polygons to correct any misalignments.

Using the Snap Preview option can significantly reduce frustration and prevent errors early on. Try using Snap Preview in your SMS projects today!

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Tips for Working with PEST

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
Model calibrated using PEST

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
PEST with pilot points

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.

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Modeling a Dam in WMS for Use in HEC-HMS

Do you have a project that requires modeling a dam, or similar structure, in HEC-HMS? WMS can make this process smoother with tools designed to help define the structure quickly and efficiently.

This blog presents a workflow for modeling a dam in WMS to later analyze in HEC-HMS. The workflow is as follows:

  1. Begin with a delineated watershed with attributes defined.
  2. Determine where you would like to place your reservoir and place an outlet point there.
  3. Delineate your watershed and compute basin attributes using your new outlet point.
  4. Create a simulation in HEC-HMS and compare the runoff from the upper basin to the lower basin in order to size your reservoir.
  5. Convert the outlet node to a reservoir.
    1. Switch to Hydrologic Modeling Module.
    2. Using Select outlet tool, select the outlet at the location where you want to model a reservoir.
    3. Right-click and select Add | Reservoir.
  6. Select Calculators | Detention Basins.
  7. Click Define to bring up Storage Capacity Input.
    1. For a dam: Use DEM and enter the height of the desired dam.
    2. Click OK to exit Storage Capacity Input dialog. The Detention Basin Analysis dialog will appear.
    3. Define the storage curve for your reservoir.
    4. Click Map to Hydrologic Model to open Map to Model. Name the series as desired.
  8. Double-click on the reservoir point to open the HMS Properties dialog.
    1. Here, you can choose the storage curve defined earlier, and define all other curves.
    2. To add an orifice to your dam, select Orifice Outlet from the Outlet Type drop-down.
      1. Define the orifice Center Elevation, Cross-sectional Area, and Discharge Coefficient.
    3. To add a spillway, select Broadcrested Spillway or Ogee Spillway from the Spillway Type drop-down.
      1. Define the required characteristics for the selected spillway.
    4. You can also choose to model an overflow type and dam break type if desired.

With the dam, spillway and orifice defined, you can now run your model through HEC-HMS again to see how your reservoir will perform under the selected storm.

Dam analysis in HEC-HMS

Try out modeling dam structures and other applications in WMS today!

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Using the Simulation Run Queue

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.

Simulation Run Queue

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!

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Troubleshooting MODFLOW, Part 2

A while back on this blog, we discussed troubleshooting MODFLOW errors. That blog post specifically discussed making use of the Model Checker, the MODFLOW command line output, and the output file. It also gave a few tips on how to fix your model when an error is encountered.

We wanted to expand on this, and specifically discuss what to do when you model doesn’t converge. When the model does not converge, an error message should appear in the MODFLOW command line output.

MODFLOW Not Converging

Essentially, when a model doesn’t converge component of the model has not been setup correctly. This inaccurate component may only cause the model to not converge when certain conditions have been met, but otherwise the model will converge when those conditions are not present.

As for why your model converges sometimes and not others, there are a wide range of possible causes for instability. Here are a few general suggestions for helping MODFLOW converge:

  • Check model inputs for reasonableness.
  • Try running the model with different solvers. There are several solvers to choose from, and each of them have their own strengths and weaknesses. To switch solvers, select MODFLOW | Global Options | Packages and then select a different solver in the lower left area of the MODFLOW Packages dialog.
  • Try changing the solver parameters.
  • Check the troubleshooting items for a model that is not converging can be found under item K of the Frequently Asked Questions section of the Online Guide to MODFLOW.
  • Deselecting the "Enable saving of computed flows for all source/sink objects" option in the MODFLOW Output Control dialog.
  • Reduce the time step length for the model run.

It can take some time to review the model to discover why it is not converging, but the effort it worth it for an accurate result. For more in-depth assistance with model troubleshooting, please consider reaching out to Aquaveo’s consulting team.

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Delineating a Floodplain Using a Scatter Point File

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
flood delineation

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!

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Converting Elevations to Depths

Have you ever found that the geometry data you’ve imported into your project is in elevation units, but the model you are using requires depth units? Using the the wrong topographic (elevation) or bathymetric (depth) data type can cause significant inaccuracies in your model results. It can also cause a lot of frustration. Therefore, it is always recommended to ensure you are using the correct data before running your model. SMS provides a way to change your data from elevation to depth (or vice versa) after it has been imported into your project.

Ideally, the correct bathymetry data will be used before assigning it to a geometry (2D Mesh, Cartesian Grid, etc.). When the original bathymetry dataset is incorrect, a new dataset should be created using the correct type (e.g., depth instead of elevation). The Data Calculator allows creating new datasets in SMS. This is done in the Scatter module by doing the following:

  1. Open the Dataset Toolbox
  2. Select the Data Calculator
  3. Select the scatter set
  4. Multiply the scatter set by -1
  5. Compute the new scatter set
  6. Use the new scatter set when generating the geometry
GSSHA

An elevation dataset can also be changed to a depth dataset with an existing geometry that has already been generated. This is done by doing the following:

  1. Open the Dataset Toolbox
  2. Select the Data Calculator
  3. Select the current elevation dataset and add it to the expression
  4. Multiply the dataset by -1
  5. Compute a new dataset

After creating the new elevation set, it needs to be designated as the elevation/depth for the geometry.

  1. Use the Data | Map Elevation command
  2. Select the new depth dataset

Now that you know how to change a dataset from elevation to depth, you can avoid the frustration of having the wrong data in your project. Try out the Data Calculator and other tools in SMS today!

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Exporting and Importing to MODFLOW 6

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. MODFLOW6
  3. In the dialog, turn on the Save MODFLOW 6 copy option under the MODFLOW Version section.
  4. Save your project.
  5. Open MODFLOW | Advanced | Run MODFLOW Dialog... to run the MODFLOW 6 files.
  6. 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).
  7. 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.
  8. Run MODFLOW.
  9. 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.

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New CityWater Pricing

Are you looking at using CityWater? CityWater is a great way to manage water distribution using cloud-based technology.

Recently, Aquaveo changed its pricing system for purchasing a CityWater license. The old system of standard and professional licensing has been modified. When purchasing CityWater, you can now configure CityWater to meet your needs.

Begin by going to the CityWater Pricing page. This page will show you all of the options that can be included in your license. The top of the page shows the core components included in all CityWater licenses. After the core components, a list of components included with each add-on package is shown. Make a note of the add-ons packages needed for your projects and the number of pipes in your largest project before clicking the Configure button.

On the CityWater License Configuration page, you will select the specific features for your license.

GSSHA

Start with entering the number of pipes in your largest EPANET model that will be used in CityWater. This does not limit the number of models that can be uploaded into CityWater, only the size of model. For example, if your largest EPANET model contains 1500 pipes, you could upload any number of models that contain 1500 pipes or fewer.

If later you find that you need to upload a larger model, contact Aquaveo to receive a quote for adding a larger model.

After entering the number of pipes for your largest model, you can select the packages to add to the license. The components of each package are described in the previous page. If later you discover you need a package that wasn’t originally purchased, contact Aquaveo to receive a quote.

Finally, if you are interested in purchasing an Enterprise License of CityWater, you will need to contact Aquaveo for a customer quote. The price for an Enterprise License depends on the number of additional licenses you will be acquiring and the components of each of those licenses.

When configuring your license, the Subscription Summary will automatically update with a quote based on the number of pipes in your largest model and the selected packages. Clicking Add to Cart will take you to the final page where you can review and pay for your order.

If you have any questions about purchasing CityWater or how CityWater can help you, don’t hesitate to contact us at sales@aquaveo.com.

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Using the Channel Calculator in WMS

With WMS there is no need to sit and calculate your channel properties by hand, you can use the Channel Calculator to help you obtain the hydraulic data you need. The Channel Calculator, a function of the Hydraulic Toolbox, has the ability to give values for flow, depth, area of flow, wetted perimeter, hydraulic radius, average velocity and so much more. Even better, the Channel Calculator only requires some basic cross-section data including the slope and either the flow or depth of the channel.

This blog post will cover how to compute depths for your channels, which can be used to create floodplain delineation maps, and also how to generate rating curves for your channels, which can be used for things such as predictions. To get started, make sure you have cross-section arcs and river centerlines in your model.

To Compute Depths:

The Channel Calculator is a good tool for approximating channel flows or flow depths. Given a flow rate, the Calculator can compute a flow depth, and vice versa.

  1. In the Hydrologic Modeling Module, select Calculators | Channels to open the Channel Calculations dialog.
  2. Toggle on the Use Cross-Section Database option to enable the ability to import existing cross-section data.
  3. Click the Select Cross Section button to bring up the Assign Cross-Section dialog.
  4. Select your cross-section file along with the cross-section you would like to work with.

The cross section displays in the small graphics window of the Channel Calculations dialog. Adjust the Z scale using the drop-down menu to better visualize the cross section. With the cross section selected, set the necessary parameters to perform calculations for depths.

  1. Click the Launch Channel Calculator button to open the Channel Analysis dialog.
  2. Enter a value for Longitudinal slope. This is an estimate for the ground slope in the vicinity of your cross-section.
  3. Enter a value for the Flow or the Depth depending on which values you have and which ones you are trying to find.
  4. Select the Calculate button. This will populate the right-side of the dialog with hydraulic values calculated for the cross-section.
  5. Select the Create Stage Point button in the Channel Calculations dialog to create a stage point based off the values computed in the channel calculator. This is useful if you are planning to use the depths to delineate a floodplain later on.
To Generate a Rating Curve:

The Channel Calculator can also be used to create different rating curves, to be used to calculate things such as storage potential.

  1. Click on the Launch Channel Calculator button to open the Channel Analysis dialog.
  2. Select the Compute Curves button to open the Curve Selection dialog.

The default is to create a rating curve for the entered flow vs. depth for the selected cross section, but it’s possible to also create curves for all of the other options listed.

  1. When exiting the Curve Selection dialog, the selected rating curves are generated and the plot shouldappear.
  2. If you double-click in the rating curve plot window a dialog will appear that presents many different options for how you can use the rating curve, including an option to export the curve in a chosen format.

As you can see, with just a few steps, you can obtain the hydraulic data you need for your channels in WMS. Try it out today!

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