It is often useful to map differences between DEMs to evaluate 2D sediment models. You can do this right in HEC-RAS using the RASter calculator. This video shows you how.
Cameron Ackerman wrote the User Manual for the RASter calculator, and you can find more about it here:
https://www.hec.usace.army.mil/conflu...
This video was funded by the HH&C SET Program.