Yes, junctions are in RiverCAD. Select Reach | Junctions. You need to have at least 3 reaches in order to have a junction (as you do in HEC-RAS).
If you don't have the latest RiverCAD, you will need to download it off of our website, at:
http://www.bossintl.com/products/dow.../RiverCAD.html
Let me know if you need any other assistance.
Sincerely,
Chris Maeder, M.S., P.E.
Senior Technical Engineer
chris.maeder@bossintl.com