Import HEC-RAS cross-section data

Flood Modeller allows you to read in cross-sections defined in HEC-RAS models, automatically converting them to Flood Modeller 1D River Sections. HEC-RAS cross-section information is contained in one or many geometric files. These are text format files with file extension “.g01”, “.g02”, “.g03”, etc. In Flood Modeller you can import these data into a new 1D network or append to an existing 1D network. 

The sections will be georeferenced if the HEC-RAS sections include georeferencing information. In addition, roughness data, distance to next section and any panel markers (where roughness changes across a section) will be extracted from the HEC-RAS data and included in your new 1D River Sections.

To import HEC-RAS data into a 1D network:

1. Right-click on the network table and select File > Import from HEC-RAS from the displayed menu.
2. Browse to the HEC-RAS geometry file (e.g. “*.g01”).
3. Prefix names to be used for all River Sections will have been automatically determined by Flood Modeller. Edit the label prefixes if required. Then click OK to proceed.
4. A new window will list all available cross-sections. Select the cross-sections to import.
   
   Note:

   Use Ctrl or Shift keys to select groups of sections, or depress Ctrl+A to select all sections in the table.
5. Add the selected cross-sections by clicking on them and dragging them to 1D River Network table. Drop the data onto a row and it will be added below this row - drag the data to the row labelled General if working with a new (empty) network. 
   Note:

   Instead of drag and drop, you can use Ctrl+C to copy sections, then right-click on the Network table and select Paste.
6. Your network table and map view are populated with new River Sections from the selected HEC-RAS sections. Save the changes to your network to store the new section information.
7. Finally, always double-check the correct units are specified for the network, i.e. SI (metric) or US. To do this, double-click the General row of the network to display properties such as units used.
   
   Note

   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 view. This sometimes requires two attempts to work.