Alluvium Alluvium 09/10/26 “What is loose sediment deposited by flowing water?” Flowing water erodes sediment and turns it loose. The water will then deposit the sediment as Alluvium. Alluvium soil is typically mixed from a wide range of different grain sizes. Share this: Share on X (Opens in new window) X Share on Facebook (Opens in new window) Facebook Like Loading... Earth/Climate scienceEngineeringUrban Systems