Skip to Main Content
Substrate controls on the longitudinal profile of bedrock channels: Implications for reach-scale roughnessAuthor(s): Jaime R. Goode; Ellen Wohl
Source: Journal of Geophysical Research-Earth Surface. 115: F03018. doi:10.1029/2008JF001188.
Publication Series: Miscellaneous Publication
View PDF (802.28 KB)
DescriptionIn this paper we examine the relationships among bedrock properties and hydraulics in shaping bedrock channel morphology at the reach scale. The Ocoee River and four other bedrock streams in the Blue Ridge province of the southeastern United States, which have reach scale differences in bedrock erodibility controlled by lithologic and structural variation, are the focus of this study. We describe a simple conceptual model for concentrated erosion in bedrock channels and test three hypotheses in order to investigate the interactions among rock erodibility, characteristics of undulating rib like bed forms, reach scale gradient, and hydraulic roughness and energy dissipation. Substrate differences correlate with variation in reach morphology (i.e., gradient, bed form orientation, and amplitude), such that less erodible substrates are associated with steeper reach gradient and with transversely oriented ribs of greater amplitude. One dimensional modeling in HEC RAS indicated that in the reach with the least erodible substrate and greatest bed slope and rib amplitude, the reach averaged hydraulic roughness was the greatest. Increased hydraulic roughness in steeper reaches points to the importance of positive and negative feedbacks in these systems: Greater substrate erosional resistance limits profile lowering, which likely creates steeper bed slopes and greater stream power, creating a self-enhancing feedback. This local increase in stream power is balanced by increased roughness resulting from the erosional processes that produce bedrock ribs, which represents a self regulating feedback. The overall result reflects quantifiable adjustments between substrate resistance and hydraulic driving forces in bedrock channels.
- You may send email to firstname.lastname@example.org to request a hard copy of this publication.
- (Please specify exactly which publication you are requesting and your mailing address.)
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationGoode, Jaime R.; Wohl, Ellen. 2010. Substrate controls on the longitudinal profile of bedrock channels: Implications for reach-scale roughness. Journal of Geophysical Research-Earth Surface. 115: F03018. doi:10.1029/2008JF001188.
Keywordsbedrock properties, bedrock channel morphology, reach scale
- Lithological and fluvial controls on the geomorphology of tropical montane stream channels in Puerto Rico
- Effects of hydraulic roughness on surface textures of gravel-bed rivers
- Pool spacing in forest channels
XML: View XML