detention basin vs river basin

detention basin and river basin both are nouns.

Word	Noun	Adjective	Verb	Adverb
detention basin	Yes	No	No	No
river basin	Yes	No	No	No

As nouns, river basin is a hypernym of detention basin; that is, river basin is a word with a broader meaning than detention basin:

detention basin: a storage site (such as a small reservoir) that delays the flow of water downstream
river basin: the entire geographical area drained by a river and its tributaries; an area characterized by all runoff being conveyed to the same outlet

Other hypernyms of detention basin include basin, catchment area, catchment basin, drainage area, drainage basin, watershed.

detention basin (noun)	river basin (noun)
a storage site (such as a small reservoir) that delays the flow of water downstream	the entire geographical area drained by a river and its tributaries; an area characterized by all runoff being conveyed to the same outlet