Aluvial

Aluvial is an adjective used in geology, geography, and soil science to describe features related to alluvium—the sediment transported and deposited by rivers and streams. It is a variant spelling of alluvial, and although still seen in some texts, it is far less common in contemporary English. The term stems from Latin alluvium, referring to washed-up sediment.

Aluvial deposits form where flowing water decelerates, dropping suspended and bedload materials. They are typically well sorted and layered, with material chosen by the energy of the transporting system. Typical settings include river floodplains, alluvial terraces, and alluvial fans at the foot of topographic highs. Soils developed in aluvial materials, called aluvial soils or alluvial soils, are usually fertile, enriched by sediments from upstream sources.

Compared with other sediment-transport regimes, aluvial deposits are distinguished from aeolian (wind-blown) and glacial deposits and from colluvial deposits produced by gravity on slopes. The study of aluvial processes informs hydrogeomorphology, sedimentology, and agronomy, and alluvial settings preserve archives of ecological and climatic change in their stratigraphy.

Note: The more widely used term in English is alluvial; aluvial remains a recognized variant in some dictionaries and in non-English contexts.