The XS Specific Bed Change Options override the global bed change options for any cross section that has them.  In the figure below, most cross sections use the veneer method in the channel (erosion and deposition) and the overbank (deposition only) but overrides the channel deposition with the reservoir method, to apply that method in the delta of the reservoir.

Bed Change Methods Should Apply to Morphologically Similar Reaches, not to Individual Cross Sections

Just because HEC-RAS allows users to define different bed change methods for each cross section, does not mean they should.  This method should not change from cross section-to-cross section.  If you do choose to override the default method, it should be for a particular reason over a coherent morphological setting, usually comprising a set of consecutive cross sections.

Examples of appropriate application of these local bed change methods would be:

  • Choosing the Reservoir method for channel deposition along the topset slope of a reservoir delta while the Veneer method is the default elsewhere.
  • Using the Simplified CEM method to compute erosion for a dam removal through the reservoir deposits, but default to the Veneer method for erosion downstream of the dam.

River Reach Bug Workaround

Bug: The XS Specific Bed Change Options do not update the grid.  

But this data table reflects the main sediment editor.  If you close this editor, and then use the River and Reach drop down menus to select the reach you want to edit, that reach will show up in this editor.

Change Bed Change Methods for Sub-Reaches Not Individual Cross Sections