Skip to Main Content
Controls on valley width in mountainous landscapes: the role of landsliding and implications for salmonid habitatAuthor(s): C. May; J. Roering; L.S. Eaton; K.M. Burnett
Source: Geology. 41(4): 503-506
Publication Series: Scientific Journal (JRNL)
Station: Pacific Northwest Research Station
PDF: View PDF (452.19 KB)
DescriptionA fundamental yet unresolved question in fluvial geomorphology is what controls the width of valleys in mountainous terrain. Establishing a predictive relation for valley floor width is critical for realizing links between aquatic ecology and geomorphology because the most productive riverine habitats often occur in low-gradient streams with broad floodplains. Working in the Oregon Coast Range (western United States), we used airborne lidar to explore controls on valley width, and couple these findings with models of salmon habitat potential. We defined how valley floor width varies with drainage area in a catchment that exhibits relatively uniform ridge-and-valley topography sculpted by shallow landslides and debris flows. In drainage areas >0.1 km2, valley width increases as a power law function of drainage area with an exponent of -0.6. Consequently, valley width increases more rapidly downstream than channel width (exponent of -0.4), as derived by local hydraulic geometry. We used this baseline valley width-drainage area function to determine how ancient deep-seated landslides in a nearby catchment influence valley width. Anomalously wide valleys tend to occur upstream of, and adjacent to, large landslides, while downstream valley segments are narrower than predicted from our baseline relation. According to coho salmon habitat-potential models, broad valley segments associated with deep-seated landsliding resulted in a greater proportion of the channel network hosting productive habitat. Because large landslides in this area are structurally controlled, our findings indicate a strong link between geologic properties and aquatic habitat.
- You may send email to email@example.com to request a hard copy of this publication.
- (Please specify exactly which publication you are requesting and your mailing address.)
CitationMay, C.; Roering, J.; Eaton, L.S.; Burnett, K.M. 2013. Controls on valley width in mountainous landscapes: the role of landsliding and implications for salmonid habitat. Geology. 41(4): 503-506.
Keywordsdebris flow, stream channel, salmon habitat
- Structures linking physical and biological processes in headwater streams of the Maybeso watershed, Southeast Alaska
- Quaternary geology and geomorphology of the lower Deschutes River Canyon, Oregon.
- Geomorphic controls on salmon nesting patterns described by a new, narrow-beam terrestrial-aquatic lidar
XML: View XML