Stream geomorphology and classification in glacial-fluvial valleys of the North Cascade Mountain Range in Washington State

In the Pacific Northwest, A Classification of Natural Rivers developed by Dave Rosgen (1994) has been the focus of much debate concerning the question of bankfull relevance to channel shaping flow, classification and stream restoration. This study is important because hydrologists and restoration technicians alike need to know whether Rosgen's bankfull indicator-based classification system can systematically and consistently apply to both east and west slope streams of the North Cascade Mountain Range. If so, do bankfull indicators provide consistent relationships to drainage area and other stream dimensions? Can geomorphic stream classification be implemented with consistency and accuracy on both east and west side slopes within glacial-fluvial valleys? Because Rosgen's system depends on dimensions based on stable, reference reaches, it is critical that measurable attributes for assessment of stability be identified. To meet reference site conditions, these attributes must be reproducible and show consistent relationships to bankfull indicators. The research present here demonstrates that bankfull indicators and geomorphic stream dimensions can be applied with consistency for stream classification in glacial-fluvial valleys on both east and west slopes on the North Cascade Mountain Range. A tool for stream stability based on reference reach dimensions was developed and described.