down drift of the ebb shoal. Bypassing occurs by sediment entering the channel from the south
(updrift), and it can then be moved offshore by tide, as well as by material transported from the
ebb shoal.
Fig. 12. Change in depth and transport vectors at hr 99, storm wave
Case 4: Tide and Fair-Weather Wave
Morphology change and transport vectors for combined tide and fair-weather wave forcing
are shown in Fig. 13 at flood and ebb. Patterns of morphology change are similar to those for the
fair-weather wave simulation (no tide) (Fig. 11), indicating that the waves are the dominant
transport mechanism. However, the tidal currents do modify the transport patterns. The tip of
the north jetty experiences greater erosion with tide and waves than with waves only, and the tip
of the south jetty experiences less erosion. Comparison of Figs. 10, 11, and 13 indicates that
waves dominate the bypassing and move material over the ebb shoal. In the interior of the inlet,
transport by tide dominates that of waves.
Case 5: Tide and Storm Wave
Transport vectors and morphology change for the tide combined with storm waves are shown
in Fig. 14. Changes in bathymetry for this simulation show little difference from the case with
storm waves only, indicating the dominance of the waves in sediment transport. The most
notable difference between the two simulations (Figs. 12, 14) is that the distance material is
transported northward from the ebb shoal is reduced with the presence of the tide (the red band
on the north side of the shoal is wider in the case with tide only). A reduction in the material
carried away from the shoal in this region probably owes to flood tidal currents that weaken the
north-directed wave-driven currents over the northern portion of the ebb shoal.
Militello and Kraus
11
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