Still haven't learned how to reply yet. It gets downright mortifying.
Once again!
I do believe that other river is the Bassac. It is in effect a distributary of the Mekong, but only connects to it well into Cambodia.
Try this map:
http://www.dams.org/images/maps/map_mekong.htm
There was a swifty outfit operating on the Bassac. I'll try to get more.
Fantastic! I'll hold off sending all this to Hugh and Capt's Quarters till that's resolved or dead-ends.