It keeps emptying water out. The mouth of the river doens't change shape or anything. It just is the part of the river when the river empties into a lake or ocean, etc.
The mouth of a river is where it empties into another river, a lake, a sea, or an ocean.
mouth of the river
The part of a river that empties into a body of water is called the mouth of the river
A river - the "river-mouth" is where it empties into the sea or a lake.
the Amazon empties in the Atlantic Ocean
That's the river mouth - or 'delta'.
Mouth
a mouth is a place where a river empties into a larger body of water.
the Amazon empties in the Atlantic ocean
At the point the river empties into a lake or ocean.
It is usually referred to as the mouth of the river.
That is the mouth of the river.