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Valley segments, stream reaches, and channel units

Bisson, Peter A., Montgomery, David R., Buffington, John M. 2006. Valley segments, stream reaches, and channel units. In: Hauer, F. R.; Lamberti, G. A., eds. Methods in Stream Ecology. Second Edition. San Diego, CA: Academic Press. p. 23-49.

Valley segments, stream reaches, and channel units are three hierarchically nested subdivisions of the drainage network (Frissell et al. 1986), falling in size between landscapes and watersheds (see Chapter 1) and individual point measurements made along the stream network (Table 2.1; also see Chapters 3 and 4). These three subdivisions compose the habitat for large, mobile aquatic organisms such as fishes. Within the hierarchy of spatial scales (Figure 2.1 ), valley segments, stream reaches, and channel units represent the largest physical subdivisions that can be directly altered by human activities. As such, it is useful to understand how they respond to anthropogenic disturbance, but to do so requires classification systems and quantitative assessment procedures that facilitate accurate, repeatable descriptions and convey information about biophysical processes that create, maintain, and destroy channel structure.

Keywords: valley segments, stream reaches, channel units, drainage network, landscapes, watersheds, spatial scales

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Title: RMRS Other Publications: Valley segments, stream reaches, and channel units
Electronic Publish Date: July 20, 2007
Last Update:
July 20, 2007

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