Geomorphological stream channel classification in aquatic habitat restoration: Uses and limitations

Abstract Land managers in western North America have embraced classification of stream channels based on geomorphological characteristics as the importance of channel stability in successful restoration of aquatic and riparian habitat has become widely recognized. Classification can permit rapid inventory of large regions, provide a stratified geomorphological framework within which more detailed observations can be organized, and provide an initial basis for selecting restoration strategies. Existing classifications are arbitrary, developed by creating classes out of a continuum of channel form. Moreover, stream channels are dynamic, and the existing condition does not necessarily reflect former, long‐term, or future conditions. The user should not confuse the classification exercise with a complete understanding of the channel. Before any channel works are actually undertaken, site‐specific studies are essential, including historical studies to determine former channel conditions and to shed light on underlying causes for degradation of aquatic or riparian resources. When applying a classification system, the raw data collected should be reported, not simply the resultant channel classes. Channels that do not fit neatly within pre‐existing classes should be reported as such and not lumped in classes where they ‚should’︁ be.