I have successfully transferred survey or AUTOCAD generated x-section to
HEC-RAS 3.1 by having the data in text file format, in MS EXCEL. The
data should be prepared as required by HEC-RAS, i.e Left to rightlooking
downstream to upstream of the channel. Then I just cut from EXCEL and
paste in HEC-RAS cross section window.

I hope this helps.
Sillah.
sillah@envirohydro.com