Alluvion refers to the slow accretion or erosion of soil, sand, and other parts of land. Water usually causes alluvion by moving the shoreline over time. In some areas located besides rivers and oceans, land can continuously change its shape through the daily movement of water. If land becomes eroded, the owner of the property where the erosion occurred loses right to any removed part of the property. This is in contrast to avulsion where large sections of land rapidly are disconnected from the property. Usually caused by extreme weather and flooding, avulsion can cause sudden changes in the property, and property law allows the original owner to keep the dislodged portion of the land. Litigation can arise regarding whether property constitutes avulsion or alluvion because the characterization of the event determines whether the property belongs to the person who originally controlled the property or the person owning where the soil, sand, and other earth moved to.
[Last updated in November of 2021 by the Wex Definitions Team]