Avulsion

The immediate and noticeable addition to land caused by its removal from the property of another, by a sudden change in a water bed or in the course of a stream.

When a stream that is a boundary suddenly abandons its bed and seeks a new bed, the boundary line does not change. It remains in the center of the original bed even if water no longer flows through it. This is known as the rule of avulsion.

Avulsion is not the same as accretion or alluvion, the gradual and imperceptible buildup of land by the continuous activity of the sea, a river, or by other natural causes.