What a scenery! A confluence of two rivers... What are they called? Are they located at the foot of the Rockies? (I think so). A former meeting place for "coureurs des bois"?The name of the town where I have my office and "my" documentation center for environmental issues means "confluence" in the Breton language (Kemper, rendered as Quimper by the French). But the 4 rivers that meet there are rather dwarves compared to the ones on your photo.
Setu, this particular confluence is melt from glacial activity inthe Grand Tetons.