Question

ii. What is the difference between an estuary and a river?​

Answer 1

Answer:

An estuary is the zone of transition or mixing between the river source and the ocean. The mouth would be more strictly defined as the location where the river ends and the recipient water body begins. The mouth is the lower end of the river, where the river stops being river. An estuary encompasses a larger area, often including inland (upstream) from the mouth and even perhaps a portion of the ocean or bay or whatever outboard from the mouth.

The primary cause of mixing in an estuary is the variable level of the sea with the tide cycle.

Also, for me, estuary involves a salt water body but not a fresh water body, but perhaps I am not correct in that interpretation. I would not consider a river flowing into a fresh water lake to be forming an estuary, even if there is an extensive delta (there would always be a mouth). No tidal mixing.