a dry river bed
channel
The path that a stream follows is a channel.
Benthos
the flow of the river.
velocity
Delta
Tangent plane "is the floor". I never heard that the touching point has a specific name.
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.
Sea Floor Spreading
Drainage Basin
The term for the place where a tide meets a river current is called the "tidal bore." This phenomenon occurs when the rising tide enters a river channel, causing the water to flow upstream against the current.