The oxygen content of a river or stream is likely to be highest at the source. The source of the river or stream is where it originates.
Answer!-Usually the start of a river is called its source and the end of the river is called the mouth.
The source
The point at which a river forms is called a river source. The source may be from a spring, melted snow from a mountain top, or a lake with a stream flowing out from it.
A stream
There is, in fact, usually a great deal of plant life near a river because a river is usually a reliable source of water and nutrients.
A headwater is the place from which the water in the river or stream originates. It is also called the source of the river or stream
The source of a river is where it starts as a tiny stream. The other end is the mouth, where it reaches the sea.
Upstream or up river
Upstream or up river
Headwater or the source.
yamuna river