not necessarily, but usually, yes.
No, an estuary is where a river widens and flows into the sea.
it forms at the beginning of a stream or river
London isn't, but it is at the beginning of the Thames estuary.
As far as I know, A river's mouth is simply called the 'river mouth'!
A North Sea Feeder beginning with the letter Y could be the York River estuary, which connects to the North Sea via the Humber Estuary in England.
London is on the River Thames but not quite at its estuary.
The Estuary Delta
the largest estuary in Asia is the Obi river.
The estuary of a river is where the tide meets the stream. A good sentence would be, the boy lost his hat in the estuary of the river.
The River Severn is technically neither a delta nor an estuary. The River Severn is a tidal river that flows into the Bristol Channel. It has characteristics of both a river and an estuary, where the freshwater river meets the saltwater of the sea.
Yes the Delaware Bay is an estuary.
The River Thames flows into it's Estuary between the Counties of Kent and Essex. This is where it meets the North Sea.