WMS

Converting CAD Data to Feature Objects in WMS

By aquaveo on January 9, 2019

CAD data has been around for a long time and it’s one of the most readily available formats for geological data. WMS can make use of the data in a variety of ways. One of these ways is to convert CAD data into feature objects.

When CAD data for an area is available, DWG and DXF file data can be automatically converted to feature objects in WMS. Lines, points, and polygons in the CAD file can be turned into feature objects on a Map coverage for use in your WMS projects. This is done by doing the following:

  1. Import the CAD data into WMS. It will appear in the Project Explorer.
  2. In the Project Explorer, right-click on the CAD file and select CAD to | Feature Objects.
  3. In the CAD → Feature Objects dialog, select the layers to be converted to feature objects.
  4. Next, in the Clean Options dialog, select options to clean up the feature objects such as removing dangling arcs.
  5. Finally, the Properties dialog will appear letting you designate the type of coverage that will hold the new feature objects.

After you have converted your CAD data to feature objects, there are few items to keep in mind.

  • Typically, CAD data will not designate the stream direction. Make certain to check the direction of arcs generated from CAD data. Use the Reorder Streams command to fix this.
  • Polygons will not be automatically generated from polygons in the CAD data. Any enclosed arcs must be converted to polygons using the Build Polygons command.
  • It may be necessary to use the Clean Options dialog again after conversion.
  • Additional adjustments to the arcs may be necessary using the Map module tools.

Generating feature arcs from CAD data can save you a lot of time and frustration when building your watershed model. Try out converting CAD data into feature objects using WMS today!

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Working with Rain Gages in GSSHA

By aquaveo on December 19, 2018

Are you needing to add rain gages to your GSSHA model? Using rain gages to define your precipitation in GSSHA is extremely useful due to its ability to spatially model precipitation over a watershed. Combining spatially varying rainfall with the distributed parameters of GSSHA is a great way to create a fairly realistic model for your watershed.

One of the bigger challenges when simulating a storm event is finding reliable data. Although it is important to investigate the most accurate source for your particular watershed, there are websites containing NOAA and GLDAS data for not only the United States, but globally. Having many sources of compiled data all on one site makes Cuahsi’s HydroClient a very useful resource. For those using our software internationally, another possibly useful resource when gathering storm data from the Global Precipitation Climatology Centre. This gives monthly values from 1901-2013, with newer data being added frequently.

Now that you have solid data for your watershed, it is time to define your gages. To use rain gages as your precipitation input:

  1. Create a rain gage coverage.
  2. Create rain gages in their proper locations.
  3. Using the Select tool, double-click on the gage to bring up the Rain Gage Properties dialog.
    1. Set the gage type to GSSHA.
    2. Define the precipitation using either a cumulative or an incremental distribution.
    3. Beneath the Show drop-down, choose GAGES if your data is incremental, and ACCUM if your data is accumulative.
  4. Return to the 2D-Grid module and select GSSHA | Precipitation.
    1. Select Gage as the rainfall event, select Rain Gage, and choose your preferred interpolation method (Inverse distance weighted or Thiessen polygons).

For more information and specifics on working with gages in GSSHA, please take a look at the GSSHA user’s manual. WMS provides a useful and helpful resource when creating a GSSHA model, analyzing and viewing the results. Practice using rain gages as your precipitation source in WMS 11.0 today!

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WMS

How to Calculate Riprap Using the Hydraulic Toolbox

By aquaveo on November 28, 2018

Are you needing to determine the size of stones needed for riprap? Having stones that are too small will reduce the effectiveness of the riprap which could be disastrous. On the other side, having stones that are too large could cause unnecessary expense.

After defining drainage data in WMS, it is possible to calculate the riprap needed for your model using the FHWA Hydraulic Toolbox. To do this:

  1. Define your drainage data in WMS.
  2. Assign each basin attribute to an analysis method by double-clicking on the feature, and then selecting Edit Attributes…. This will give you the opportunity to link your drainage data to the Hydraulic Toolbox.
  3. Click on the Hydraulic Toolbox macro in WMS to bring up the Hydraulic Toolbox.
  4. You can calculate riprap using one of two methods:
    • Channel Lining Design Analysis Tool. Keep in mind when using this tool that a filter material must be separately designed.
    • Riprap Analysis Tool. This tool will calculate the filter material along with riprap size.

Once in the Hydraulic Toolbox, locate the name of the analysis method chosen and double-click to open the analysis dialog for the chosen parameter and method. You will notice that all of the data you input into WMS is now filled in the analysis tool. After you specify blank parameters, the tool will calculate and display the results at the bottom of the screen under “Minimum Riprap Thickness”.

Using the Hydraulic Toolbox to calculate riprap can help your project move forward. The toolbox also contains many other features worth exploring. Try using the Hydraulic Toolbox today!

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WMS

Quickly Delineating a Floodplain

By aquaveo on October 31, 2018

How many watershed projects require knowing which areas are in a floodplain? There is a lot of debate over building on floodplains, but before that debate can happen, the location of the floodplain needs to be known.

A new feature in WMS makes this process quick and simple.

The Map Flood tool utilizes ground elevations and existing flood hazard maps from the Federal Emergency Management Agency (FEMA) to quickly visualize the impacts of possible modifications in the flood level. The tool is designed to utilize data from web services including ground elevations, flood hazard base flood elevations, and flood hazard floodplain extents.

The Map Flood tool is accessed by clicking on the Map Flood icon in the toolbar.

Running the tool will do the following:

  • Download elevation data for the area which is stored as a scatter set
  • Download base flood elevation lines for the area which is stored as a map coverage
  • Download a flood extents polygon which is stored as a map coverage
  • Download a flood insurance map as a image in the GIS module
  • Create a water surface elevation for the base flood
  • Create an offset water surface elevation for the modified flood level
  • Compute a new flood extent polygon for modified flood level

For locations that do not have FEMA data, you can use your own data to generate flood extents. As long as a ground elevation dataset and a water surface elevation have been imported into a WMS project, then the Map Flood tool can be used to create a fast floodplain. This data needs to be imported into WMS as either a 2D scatter set or a TIN.

Using the new Map Flood tool can greatly reduce the time it takes to delineate a floodplain. Try out the new Map Flood tool in WMS 11.0 today!

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