alluvium
/əˈl(j)uːvɪəm
/noun [mass noun]
A deposit of clay, silt, and sand left by flowing floodwater in a river valley or delta, typically producing fertile soil.Many vineyards are located on valley bottoms underlain by alluvium which can provide deep, free-draining soils of variable grain size....
- The measured soil parameters at the sites were within the normal range for bottomland hardwood soils of Mississippi River alluvium.
- In the east, which is lower and flatter, river gravels and alluvium from the North Sea have produced dark, rich soils.
Origin
Mid 17th century: Latin, neuter of alluvius 'washed against', from ad- 'towards' + luere 'to wash'.