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Gully, California

Erosional Landform Pictures


A gully is the first sign of serious erosion of loose soil by running water, although it does not have a permanent stream in it. (more below)
Tiny dry dirt valleys
Photo (c) 2008 Andrew Alden, licensed to About.com (fair use policy)
A gully is part of a spectrum of landforms created as running water erodes sediment. Erosion starts with sheet erosion, until running water concentrates into small irregular channels called rills. The next step is a gully, like this example from near the Temblor Range. As a gully grows, the streamcourse would be called a gulch or ravine, or maybe an arroyo depending on various features. Usually none of these involve erosion of bedrock.

A rill can be ignored—an offroad vehicle can cross it, or a plow can wipe it out. A gully, though, is a nuisance to everyone except the geologist, who can get a clear look at the sediments exposed in its banks.

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