flowage vs body of water

flowage and body of water both are nouns.

Word	Noun	Adjective	Verb	Adverb
flowage	Yes	No	No	No
body of water	Yes	No	No	No

As nouns, body of water is a hypernym of flowage; that is, body of water is a word with a broader meaning than flowage:

flowage: a body of water that has been created by deliberately flooding an area
body of water: the part of the earth's surface covered with water (such as a river or lake or ocean)

Other hypernyms of flowage include water.

flowage (noun)	body of water (noun)
the act of flooding; filling to overflowing	the part of the earth's surface covered with water (such as a river or lake or ocean)
a body of water that has been created by deliberately flooding an area
gradual internal motion or deformation of a solid body (as by heat)