tidal stream vs tidewater river

tidal stream and tidewater river both are nouns.

Word	Noun	Adjective	Verb	Adverb
tidal stream	Yes	No	No	No
tidewater river	Yes	No	No	No

As nouns, tidal stream and tidewater river are synonyms defined as:

tidal stream and tidewater river: a stream in which the effects of the tide extend far upstream

Other synonyms of tidal stream include tidal river, tidewater stream.

tidal stream (noun)	tidewater river (noun)
a stream in which the effects of the tide extend far upstream	a stream in which the effects of the tide extend far upstream