the flow of the river.
a dry river bed
Flood plain, ie lowwer course or river mouth.
velocity
The path that a stream follows is a channel.
Riverbed, or simply bed.
Delta
prognosis
Of course, please provide me with the term you would like me to define.
Alluvial soil is the term that describes soil developed from silt and clay deposited by a flooding river. This type of soil is typically fertile and well-draining due to its composition.
shingles
Drainage Basin
No. It is a noun (ship's course, golf course, river course). The meaning is a path, route, or progression. Course is a noun-adjunct in the term 'three course meal' (each stage of the meal is a course or path).