tidewater river vs tidal river

tidewater river and tidal river both are nouns.

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

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

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

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

tidewater river (noun)	tidal 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