Hi Christine,
I've seen you referring to the Assign River Order toolset; however, I'm unable to locate the Assign River Order toolset under the Attribute Tools. Has it been removed in ArcHydro 2? Please see image.
Thanks,
Aslam.
There is a tool in the Arc Hydro Tools toolbox > Attribute Tools toolset called Assign River Order that will calculates the stream order using 3 different methods