This process-based, assessment scheme developed by Montgomery and Buffington utilizes basic energy and mass-balance equations to relate water and sediment flow to a number of geomorphic parameters. Those parameters, when measured in the field, are used to differentiate types of river reaches, and to assess channel condition and response potential in the case of a disturbance. The use of remote sensing is encouraged for the determination of many of the geomorphic parameters. The classification system is intended for mountain channels, but the relationships described can be more widely applied. Two tiers of classification are utilized at the valley segment (landscape scale) and channel reach scales. Both classifications segregate categories along a continuum of sediment transport from transport limited (sediment supply exceeds river's ability to transport it) to supply limited (the river's energy to move sediment far exceeds the delivery of sediment to the channel).
W = channel width
D = flow depth
Ds = scour depth
d50 = median bed grain size
n = roughness coefficient
Ss = sediment storage
S = water surface slope
Montgomery, David R., 2008, Dreams of Natural Streams. Science, 319, 291-292
Bisson, Peter A.; Buffington, John M.; Montgomery, David R. 2006. Chapter 2: Valley Segments, Stream Reaches, and Channel Units in Methods in Stream Ecology, Hauer, F. Richard and Lamberti, Gary A. Editors. Second edition, Academic Press; El Sevier. Pages 23-49.
Montgomery, David R. (2003) Predicting landscape-scale erosion rates using digital elevation models. C. R. Geoscience, 2003, 335, 1121-1130
Montgomery. D. R., and J. M. Buffington. 1998. Channel processes, classification, and response in R. J. Naiman and R. E. Bilby (eds.), River Ecology and Management: Lessons from the Pacific Coastal Ecoregion. Springer, New York, NY. Pages 13-42
Montgomery, David R.; Buffington, John M. (1997) Channel-reach morphology in mountain drainage basins, Geological Society of America Bulletin, (109) 5, p. 596-611