RASMapper can aggregate sediment results across a user defined line, instead of a single cell face, for Total-load concentration or Total-load discharge by grain size or by all grain sizes. 
This process requires a couple extra steps that are not totally intuitive, (It requires leaving RASMapper to view results) but it is available in 6.5. 
More parameters will be available in 6.6.

  1. Add Reference Lines to the geometry in RAS Mapper.  Remember to draw lines left to right looking downstream to have positive transport be in the downstream direction
  2. Run the model.  Reference Line output is written during the run so it’s not viewable unless you run the model after creating the lines (or points or areas).
  3. Return to the main RAS Interface and open the Stage and Flow Hydrograph Tool. 
  4. From the hydrograph viewer choose the Type, menu and select Reference Line.  You can then choose which reference line you want to view.

5. From Options, select Variable and you will see a pop-up with your options.  If you want to see this in tabular form, right click in the window and select Tabulate All Similar Charts.