Understanding processes controlling sediment transports at the mouth of a highly energetic inlet system (San Francisco Bay, CA)

Mobility of meso-scale morphology on a microtidal ebb delta measured using remote sensing

“…According to results obtained through numerical model simulated at NRI by Chen et al (2012), the residual flow velocities present such patterns, especially when the waves are included in the simulations. Similar patterns were also observed by Elias and Hansen (2013)) at the San Francisco inlet through the use of numerical modeling. Thus, the sand transport by flood flow toward the inlet is, in part, restricted by the ebb jet and the sediments are recirculated back to the ebb-tidal delta, limiting the sediment bypass through into the inlet.…”

“…This interaction may generate or enhance gyres that are dynamical sediment traps that cause accumulations of sand in the swash platforms (Oertel, 1972) or may recirculate back onto the ebb-tidal delta. Elias and Hansen (2013) in their study at the Golden Gate inlet, demonstrate through the application of a numerical model differences in the ebb delta hydrodynamic patterns due to waves. Their comparison of simulations with and without waves, clearly shows that waves interacting with the dominant ebb flow result in increased sediment movement across the ebb delta, following complex patterns such as a recirculation cell in one side of the inlet, while on the other side, the waves increase the seaward and longshore transport onto and over the ebb-delta lobe platform.…”

“…Inlets probably represent one of the most challenging environments for the evaluation of sediment transport quantities related to the acting physical forces (Komar, 1996), and they have been the subject of a number of process-based models that provide valuable information on governing flow and sediment transport patterns (Wang et al, 1995;Cayocca, 2001;Ranasinghe and Pattiaratchi, 2003;Van Leeuwen et al, 2003;Siegle et al, 2004Siegle et al, , 2007Elias and Spek, 2006;Van der Vegt et al, 2006;Elias and Hansen, 2013). However, most of the previous studies have been focused on what might be called the macro-scale morphology of ebb shoals and channels, describing the ebb-tidal delta in terms of a small number of sediment lobes and channels.…”

Morphological and sedimentological response of a mixed-energy barrier island tidal inlet to storm and fair-weather conditions

“…The model system Delft3D has been widely tested in morphodynamic modeling studies for various environments (e.g., Dissanayake et al, 2009;Lesser et al, 2004;Van der Wegen and Roelvink, 2012), yet it has been verified in comparably few morphological studies on nonidealized tidal inlets that take into account a real-world bathymetry (e.g., Elias and Hansen, 2013;Elias and van der Spek, 2006;Elias et al, 2012). The validation of simulated morphodynamics by field observations is generally difficult as in situ data are scarce and only available for very limited areas, if at all.…”

“…Sha and Van den Berg (1993) developed a descriptive model to explain ebb-tidal delta symmetry, i.e., the orientation of the seaward inlet channel with respect to shallow ebb-delta shoals, as a response to the relative direction of waves to the interplay of tidal currents alongshore and within the inlet. Very few studies at mixed-energy tidal inlets have investigated the complex interaction of tideand wave-driven processes and distinguished the contribution of each agent to residual sediment fluxes and morphological changes (e.g., Bertin et al, 2009;Elias and Hansen, 2013;Sha, 1989). Even fewer studies have managed to relate observed distributions of surface sediment grain sizes at tidal inlet systems to distinct physical drivers (e.g., Sha, 1990;van Lancker et al, 2004).…”