alluvium vs alluvial deposit

alluvium and alluvial deposit both are nouns.

Word	Noun	Adjective	Verb	Adverb
alluvium	Yes	No	No	No
alluvial deposit	Yes	No	No	No

As nouns, alluvium and alluvial deposit are synonyms defined as:

alluvium and alluvial deposit: clay or silt or gravel carried by rushing streams and deposited where the stream slows down

Other synonyms of alluvium include alluvial sediment, alluvion.

alluvium (noun)	alluvial deposit (noun)
clay or silt or gravel carried by rushing streams and deposited where the stream slows down	clay or silt or gravel carried by rushing streams and deposited where the stream slows down