Rosgen Type G Streams

January 25, 2012 Print Friendly and PDF
A "G" Channel Type.
Photo courtesy of the National Riparian Service Team.

Type G streams or “gullies” are entrenched, narrow, and deep, step/pool channels with a low to moderate sinuosity. Channel slopes are generally steeper than 0.02%, although G channels may be associated with gentler slopes where they occur as down-cut gullies in meadows. Type G streams are found in a variety of landtypes including alluvial fans, debris cones, meadows, or channels with older relic channels. The “fanhead trench” which is a channel feature deeply incised in alluvial fans is typical of G type stream channels. With the exception of those channels containing bedrock and boulder materials, Type G streams have very high bank erosion rates and a high sediment supply, resulting in high bedload and suspended sediment transport rates. Channel degradation and sideslope rejuvenation processes are typical. Cobble, gravel, and sand-bed G channels are often a failed or failing Type B or E channel.


Montana Stream Management Guide for Landowners, Managers, and Stream Users. 1998. Montana Dept. of Environmental Quality. 34 pp.

Rosgen, D. L. (1994). A classification of natural rivers. Catena, 22, 169-199.

Rosgen, D.L. and H.L. Silvey. 1996. Applied River Morphology. Wildland Hydrology Books, Fort Collins, CO.

Surber, Gene and Bob Ehrhart. 1998. Stream and Riparian Area Management. Montana State University Cooperative Extension Service.

United States Environmental Protection Agency. 2008. Fundamentals of the Rosgen Stream Classification System. USDA EPA Watershed Academy. Accessed on 17 May 2010.

Ward, A., J. L. D’Ambrosio, and D. Mecklenburg. 2008. Stream Classification. The Ohio State University Extension. Agriculture and Natural Resources Fact Sheet AEX-445-01.

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This work is supported by the USDA National Institute of Food and Agriculture, New Technologies for Ag Extension project.