HR: 16:15h
AN: B44B-04    [Abstracts]
TI: Interactions of geomorphic process and form associated with Chinook salmon spawning habitat on the Yuba River, northern California.
AU: * Moir, H J
EM: hjmoir@ucdavis.edu
AF: University of California, Davis, One Shields Avenue, Davis, CA 95616 United States
AU: Pasternack, G B
EM: gpast@ucdavis.edu
AF: University of California, Davis, One Shields Avenue, Davis, CA 95616 United States
AB: The study identifies the links between channel form, physical process and habitat utilisation at a site on the Yuba River that annually experiences high levels of spawning activity by chinook salmon (Oncorhynchus tshawytscha). Such relationships control the provision of suitable habitat conditions and are responsible for the longer-term maintenance and evolution of the geomorphic features that support spawning. Data of this nature are essential to provide the basis for sustainable rehabilitation designs that are sympathetic to natural geomorphic and ecological processes. An initial assessment linked a 2-D hydrodynamic, sediment entrainment, and physical habitat model of the site resolved at the micro-habitat scale (0.1-1.0 m, the scale at which fish actually experience a river) with over 400 redd positions. At the micro-habitat scale, the model described the hydraulic (i.e. depth, velocity, Froude number, shear stress) environment associated with spawning site utilisation. Habitat suitability indices (HSIs) for spawning Chinook salmon were applied to model output to predict habitat availability that was then compared to actual redd distributions at the site. Micro-habitat scale information was then nested within a 10-100 m scale geomorphic context to identify discrete hydraulic-morphological habitat types, assess cross-section geomorphic conditions, and predict sediment transport rates. Using the 2D model and tracer experiments, information of sediment mobility over a range of discharges provided an indication of the processes that control the sedimentology of the site and, ultimately, the distribution of habitat.
DE: 1815 Erosion and sedimentation
DE: 1824 Geomorphology (1625)
DE: 1860 Runoff and streamflow
SC: Biogeosciences [B]
MN: 2005 Joint Assembly