What is a River?
A body of natural fresh water that flows from high land to low land. Rivers begin at the source which can be a pond, a lake, a stream waterfall or other bodies of water. Rivers flow to the sea or ocean. Where the river meets the sea or ocean is known as the mouth of the river.
See https://www.youtube.com/watch?v=7kgQNRQjIUU
River Processes
There are three (3) river processes:
River Erosion
River Transport
River Deposition