Controls on valley width in mountainous landscapes: The role of landsliding and implications for salmonid habitat

Abstract

Research Article| April 01, 2013 Controls on valley width in mountainous landscapes: The role of landsliding and implications for salmonid habitat C. May; C. May 1Department of Biology, James Madison University, Harrisonburg, Virginia 22807, USA Search for other works by this author on: GSW Google Scholar J. Roering; J. Roering 2Department of Geological Sciences, University of Oregon, Eugene, Oregon 97403, USA Search for other works by this author on: GSW Google Scholar L.S. Eaton; L.S. Eaton 3Department of Geology and Environmental Science, James Madison University, Harrisonburg, Virginia 22807, USA Search for other works by this author on: GSW Google Scholar K.M. Burnett K.M. Burnett 4U.S. Forest Service Pacific Northwest Research Station, Corvallis, Oregon 97331, USA Search for other works by this author on: GSW Google Scholar Author and Article Information C. May 1Department of Biology, James Madison University, Harrisonburg, Virginia 22807, USA J. Roering 2Department of Geological Sciences, University of Oregon, Eugene, Oregon 97403, USA L.S. Eaton 3Department of Geology and Environmental Science, James Madison University, Harrisonburg, Virginia 22807, USA K.M. Burnett 4U.S. Forest Service Pacific Northwest Research Station, Corvallis, Oregon 97331, USA Publisher: Geological Society of America Received: 22 Aug 2012 Revision Received: 10 Nov 2012 Accepted: 12 Nov 2012 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2013 Geological Society of America Geology (2013) 41 (4): 503–506. https://doi.org/10.1130/G33979.1 Article history Received: 22 Aug 2012 Revision Received: 10 Nov 2012 Accepted: 12 Nov 2012 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation C. May, J. Roering, L.S. Eaton, K.M. Burnett; Controls on valley width in mountainous landscapes: The role of landsliding and implications for salmonid habitat. Geology 2013;; 41 (4): 503–506. doi: https://doi.org/10.1130/G33979.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract A 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 do not have access to this content, please speak to your institutional administrator if you feel you should have access.