13. No-Exchange Channel Cells

13. No-Exchange Channel Cells#

The no-exchange elements can be set up for any channel left bank element. This will prevent the channel at that location from sharing discharge with the floodplain on either the left or right bank. It is a way to stop the channel from sharing between the channel and the floodplain. They can be used for channels that cross wide roadways without having to split up the channel into two segments.

../../../_images/No0021.png

Digitize No Exchange Areas#

Note

The no exchange element should be defined for left bank channel nodes only.

  1. Select the layer or the No-Exchange Channel Areas and click Toggle Editing. Create polygons over the cells that will not exchange discharge with the floodplain. Save the No-Exchange Channel Areas layer and close the editor.

../../../_images/No005.png

Sample Data#

  1. Click the Sample No-Exchange Channel Cells button in the Grid Tools and click OK when the process is complete.

../../../_images/No0021.png ../../../_images/No006.png

Note

The No-Exchange Channel Cells are added to the CHAN.DAT file with the identifier “E”.

../../../_images/No007.png

Troubleshooting#

  1. Create the No-Exchange polygons if they are missing from the No-Exchange Channel Areas.

  2. If the Grid layer is empty, create a grid and try again.

  3. If a Python error appears during the sampling process, the attribute table may be missing. Save and reload the project into QGIS and try again.

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