avulsion

noun | \ ə-ˈvəl-shən \ | avul·sion

1. : a sudden cutting off of land by flood or change in the course of a body of water; especially : one that separates a portion from one person's property and joins it to the property of another — compare accretion : one that separates a portion from one person's property and joins it to the property of another — compare accretion