a vetch is a form of:

Alluvium



noun — Plural: Alluvia, Alluviums
1.
(sand clay, etc. gradually deposited by running. water, as along a river bed) ដីល្បាប់
ENGLISH MEANING
noun — Plural: Alluvia, Alluviums
1.
Deposits of earth, sand, gravel, and other transported matter, made by rivers, floods, or other causes, upon land not permanently submerged beneath the waters of lakes or seas.