How to import EACSD cross sections
  • 02 Aug 2022
  • 5 Minutes to read
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How to import EACSD cross sections

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Flood Modeller allows you to import cross sections defined in EACSD survey files, automatically validating and converting them to Flood Modeller 1D cross sections. The procedure for importing EACSD data into a 1D network is as follows:

  1. In Flood Modeller, you can import the survey data into a new 1D network or append to an existing 1D network.To import into a new network, you first need to start a new, “empty” network. In the Home tab of the main toolbar, click on New in the Networks section. You will be prompted to give your new network a name and browse to the folder where it will be saved.

    The new network will be added to your project panel and made active. The (empty) network table for your new network will be shown to the right of the map.

  2. Right-click on the network table and select File > Import from EACSD from the displayed menu, as shown below:

    1DRiverimagesimportmenu.jpg

  3. Browse to the EACSD survey file (e.g. “*.txt”).

  4. When the survey file is selected, Flood Modeller will validate the survey data in the file; if it fails the validation the user will be prompted with a form showing the results of the validation failure.

    1DRiverimagesvalidationfail.jpg
    The error log can be saved to a file or copied to the clipboard for passing back to surveyors.

  5. If the EACSD survey file is valid, Flood Modeller reads the contents of the file, loads all the survey data, and the Specify EACSD Sections form is displayed:

    1DRiverimagesEACSDspecifysections.png

    As each file can only contain one reach, there is the option for setting the section naming convention for each section. These are Prefix + chainage and Section name in header.

    Use Prefix + chainage to set an optional prefix name for all sections with the chainage appended as the section name. The available number of characters is shown and is calculated from the maximum length of the chainage values defined in the survey file. If the prefix is longer than the available characters then a negative number is shown and the section names will be truncated to the twelve-character limit. This may cause duplication in the section names. If the prefix is blank then the chainage value is used for the section names which will be left padded with zeros.

    The Section name in header option simply uses the section name from the survey file for each section.

  6. There are two options for setting roughness values: Read from file and Use defaults.

    Read from file uses the channel roughness values based on the simplified Conveyance Estimation System (CES). Click the Set Roughness Values button to display a pop-up window listing all unique combinations of CES from the survey file in tabular form:

    1DRiverimagesroughness.jpg

    The first three columns list the CES channel roughness. These are: “Land Cover” (Vegetation, e.g. GRASS, REED) “Soil Type” (Ground/bed type, e.g. SOIL, GRAVEL) and “Floodplain Type” (Irregularity, e.g. RIDGE, MIRREG).Note the abbreviations used can be looked up in the following document: Channel Survey Data

    The next three columns are the roughness coefficients for in bank and out of bank left and right; these are populated with default values but can be modified. Click in the relevant field to enter a different value. The Reset to Defaults button can be used to reset to the default values at any time.

    Click OK to save any edited values and return to the Specify EACSD Sections form.

  7. Currently the EACSD import only reads the open channel sections from the survey file. The structures in the file are ignored but a check-box is provided (and ticked by default) to import the cross-sections associated with each structure. The structures can also be seen by clicking the View Structures button; this will show the EACSD Structures form:

    1DRiverimagesviewstructures.jpg

    Click OK to return to the Specify EACSD Sections form.

  8. Sections can be defined with both soft bed (SB) and hard bed (HB) elevation. A check-box is provided to replace SB values with HB values in the regions where these are present. Note that there can be multiple hard bed areas in a section, which are distinguished with the use of numbered flags, i.e. HB1, HB2, etc.

    1DRiverimageshardbedchosen.png

  9. Click OK to proceed to a list of available cross sections, displayed in a new window. You can select one or many sections from this table; use Ctrl or Shift keys to select groups of sections, or depress Ctrl and A keys to select all sections in the table. After selecting you can add these to your network by dragging from the table to the General row in the 1D River Network table (alternatively use Ctrl + C keys to copy sections then right-click on Network table and select Paste).

    1DRiverimagesdragsections.jpg

    Note: Drag by depressing the left mouse button on your selected EACSD sections and move the mouse cursor to the Network table, hover over the row below which you want to add the new sections (General row for an empty network) and release the mouse button.

  10. Your network table and map view are populated with the selected EACSD sections, as shown below. The sections will be geo-referenced if the EACSD sections include geo-referencing information. In addition, roughness data, distance to next section and any panel markers (where roughness changes across a section) will be extracted from the EACSD data and included in your new 1D cross sections.

    1DRiverimagesEACSDimported.jpg

    Double-click on a node to view the cross-sectional data and then click the Plot button in the node properties window to view a cross section plot:

    1DRiverimagesEACSDviewplot.jpg

  11. Save the changes to your network to store the new section information. You should then check the correct units are specified for the network, i.e. SI (metric) or US. These can be set at project level using the General settings (accessed from Home tab of main toolbar). Alternatively, double-click on the General row of a network to display “General System Parameters”, which includes the option to set specific units or default to the project level setting.

    In addition to displaying the 1D network as a series of icons, you can also show the section lines on the map by dragging the network from the Project panel onto the map (Tip: this sometimes requires two attempts to work). You can modify the section line colour by double-clicking the network layer displayed in the Layers panel (lower left corner of interface) and accessing the layer properties window. Furthermore, if you know the geo-projection of your geo-referenced data, you can add base mapping to your map view by selecting a suitable mapping source from the Base Map menu (Home tab of main toolbar). The example below shows the EACSD example displayed with Bing Hybrid mapping behind it:

    1DRiverimagesEACSDBing.jpg

  12. To complete the construction of a Flood Modeller 1D network model from your EACSD data you will need to add suitable boundary data to the upstream end (e.g. QT boundary) and downstream end (e.g. HT boundary) of the network.

More about River Section Nodes


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