sluice valve vs water gate

sluice valve and water gate both are nouns.

Word	Noun	Adjective	Verb	Adverb
sluice valve	Yes	No	No	No
water gate	Yes	No	No	No

As nouns, sluice valve and water gate are synonyms defined as:

sluice valve and water gate: regulator consisting of a valve or gate that controls the rate of water flow through a sluice

Other synonyms of sluice valve include floodgate, head gate, penstock, sluicegate.

sluice valve (noun)	water gate (noun)
regulator consisting of a valve or gate that controls the rate of water flow through a sluice	regulator consisting of a valve or gate that controls the rate of water flow through a sluice