Photo courtesy of the National Riparian Service Team.
Type D streams are multiple-channel, or braided, systems with a very high channel width/depth ratio, and a channel slope generally the same as the attendant valley slope. Type D streams are found in landforms and related valley types consisting of steep depositional fans, steep glacial trough valleys, glacial outwash valleys, broad alluvial mountain valleys, and deltas. While the very wide and shallow Type D streams are not deeply incised, they can be laterally contained in narrower or confined valleys. They are characterized by high bank erosion, large deposition occurring as both longitudinal and transverse bars, and annual shifts of the bed location. Meander width ratios are very low. Sediment supply is generally unlimited and bed features are the result of a series of various bar types and unvegetated islands that shift position frequently during runoff events. Braided channels can occur across a wide range of morphological and topographical conditions. A good example of a naturally braided system would be a glacial outwash stream in Alaska. Similar systems can be found in the deserts of the Southwest where sand is the dominant bed material.
References
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. http://www.epa.gov/watertrain/stream_class/index.htm 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.