- In Autodesk Civil 3D, open a drawing that contains a stream you would like to study, along with an existing ground surface.
- Define the stream centerline as an alignment. Be sure the stationing goes in the desired direction.
- Create a sample line group with stations at the desired section locations along the stream centerline alignment.
Note: For HEC-RAS analysis, be sure that the sample lines do not extend beyond the extents of the surface.
- Optionally, create alignments or draw polylines to represent left and/or right stream banks.
Note: The bank locations appear in the HEC-RAS application as red dots on the sections. The left and right bank locations tell HEC-RAS where the Manning’s n values change for left, channel, and right bank situations in the section. This effects the calculations and the level of water in the section.
BestPractice: It is recommended to use the same drawing for exporting data to be used in HEC-RAS that you use for importing data from HEC-RAS.