HR: 1340h
AN: H53B-1244    [Abstracts]
TI: Predictive Design Morphologies for Gravel Augmentation
AU: * Brown, R A
EM: rabro@ucdavis.edu
AF: University of California, Davis, 219 Veihemeyer Hall, LAWR, 1 Shields Avenue, Davis, Ca 95616
AU: Pasternack, G B
EM: gpast@ucdavis.edu
AF: University of California, Davis, 219 Veihemeyer Hall, LAWR, 1 Shields Avenue, Davis, Ca 95616
AB: Spawning habitat rehabilitation (SHR) is an interdisciplinary practice merging hydrology, geomorphology, aquatic ecology, and civil engineering to improve existing aquatic habitat and restoring fluvial complexity. Although SHR is widespread, it needs a science-based design process. The Spawning Habitat Integrated Rehabilitation Approach (SHIRA) is a scientifically peer-reviewed framework for doing SHR on regulated rivers. Although SHIRA has shown success with gravel augmentation on the Mokulmne River using hypothesis driven designs, the goal of this study was to evaluate several more natural processes for their potential in SHR, and to do so at the geomorphic-unit scale for the first time. Multiple design hypotheses were included in 6 SHR scenarios for rehabilitating the Lewiston Dam reach of the Trinity River, CA. Morphologies tested for their process mechanics included central bars, transverse-oblique bars, riffles, point bars, and bench-constricted pools. Varying longitudinal and lateral approach slopes for each feature were evaluated as well as feature sequencing. For each design scenario, a 2D model predicted local depth, velocity, shields stress, depth of scour, and habitat suitability for life stages of chinook and steelhead salmon at 300 and 6000 cfs. Data were analyzed to determine if conceptually expected geomorphic and ecological outcomes were in fact predicted by the 2D model. One design will be selected for actual construction in 2005 to evaluate 2D model predictions.
UR: http://shira.lawr.ucdavis.edu
DE: 1803 Anthropogenic effects
DE: 1815 Erosion and sedimentation
DE: 1824 Geomorphology (1625)
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting