Gully erosion

Definition

Gully erosion is erosion that cuts deep channels which cannot be crossed by machinery or smoothed by ordinary tillage. Gullies often start where runoff concentrates, such as a compacted track, a field gateway or a culvert outlet, and then grow upslope after heavy storms while draining the surrounding land. They are the advanced stage of a progression that begins with thin sheet erosion and small rills. Fixing the cause of the concentrated flow matters more than filling the channel. See also: Erosion, Runoff, Terrace, and the guide "Soil Erosion by Water and Wind: Mechanisms and Warning Signs".