Note that we have not created anything in RiverCAD to compute the fill volume for the encroachment area. The reason is that generally you need to manually edit the final floodway encroachment along the river, which is not a straight line. The encroachment will tend to bend along with the river and not be a straight line between cross sections. There is a bit of "art" to finalizing this encroachment.
Note that once you have created the encroachment line, you can either use Civil 3D, Land Desktop, or our Terrain Module to determine the fill volume.
Sincerely,
Chris E. Maeder, M.S., P.E.
Senior Technical Engineer
chris.maeder@bossintl.com