Modeling the effects of bed drag coefficient variability under wind waves in South San Francisco Bay

Jeremy D. Bricker, Satoshi Inagaki, Stephen G. Monismith

    Research output: Contribution to conferencePaperpeer-review

    3 Citations (Scopus)

    Abstract

    In this paper, we report the results of a study of the variation of shear stress and the bottom drag coefficient CD with sea state and currents at a shallow site in San Francisco Bay. Via field experiments, we found that the model of Styles & Glenn (2000), though formulated to predict C D under ocean swell on the continental shelf, accurately predicted enhanced drag under wind waves in an estuary (Bricker et al, 2004). Knowing this, we apply the enhanced drag coefficient determined by Styles & Glenn to the estuarine circulation model TRIM-3D of Casulli & Cattani (1994) and Gross et al (1999), and use it to examine the effects of variable roughness on contaminant and sediment transport in South San Francisco Bay. We also investigate the importance of the wave model used in TRIM-3D, by comparing the results of Inagaki et al's (2001) fetch and wave model with those of SWAN (Booj et al, 1999). The different wave models we use generate noticeably different trends in sediment transport and roughness variation. Given a wave model, we find that tidal stage in South San Francisco Bay is quite insensitive to variability in roughness, but tidally-averaged RMS and residual currents are quite sensitive (modified by about 10%), and channel-shoal asymmetry is enhanced. Along with this, the deep channel experiences more erosion of sediment, and the shoals more deposition. Furthermore, variable roughness extends the hydraulic residence time (inhibits flushing) south of the Dumbarton Bridge from 18 days to 19 days.

    Original languageEnglish
    Pages89-107
    Number of pages19
    DOIs
    Publication statusPublished - 2004
    EventEstuarine and Coastal Modeling - Proceedings of the Eighth International Conference - Monterey, CA, United States
    Duration: 2003 Nov 32003 Nov 5

    Conference

    ConferenceEstuarine and Coastal Modeling - Proceedings of the Eighth International Conference
    Country/TerritoryUnited States
    CityMonterey, CA
    Period03/11/303/11/5

    ASJC Scopus subject areas

    • Civil and Structural Engineering
    • Modelling and Simulation
    • Geotechnical Engineering and Engineering Geology

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