In contemporary English, there is no single term that denotes authoritatively the direction in which a stream or river flows. 'Stream-flow' may be used; however, 'downstream' is practically applicable and commonly used, along with a number of other equivalent terms.
The path of a river is called its "channel" or watercourse. Where a passage is through cliffs or canyons, it may be called a gorge.
none of your buisness
downstream, downhill, downriver
Course
A hop
The river could have lots of rocks and heavy currents
it was the only good route from Maryland to Ohio river
colorado river
For Christians it's called: Baptism
Mississippi river
en route they will cross a state boundary created by what river
amazon river (fail)
The river's course is its route; where it goes.
Mississippi River
He thought it was the Northwest Passage, a route to travel, by ship, from the Atlantic to the Pacific.
The Columbia River