stormwater drain vs drainage well

stormwater drain and drainage well both are nouns.

Word	Noun	Adjective	Verb	Adverb
stormwater drain	Yes	No	No	No
drainage well	Yes	No	No	No

As nouns, stormwater drain and drainage well are synonyms defined as:

stormwater drain and drainage well: a system of watercourses or drains for carrying off excess water

Other synonyms of stormwater drain include drain system, storm drain, storm sewer.

stormwater drain (noun)	drainage well (noun)
a system of watercourses or drains for carrying off excess water	a system of watercourses or drains for carrying off excess water