F.S. Buonaiuto, N.C. Kraus / Coastal Engineering 48 (2003) 5165
61
referenced to MLLW because it frequently is the
to expand the data range to higher energy inlets
controlling depth for wave propagation. The ebb jet
(Table 2). Grays Harbor, Willapa Bay, and the
is opposed by the incident waves, which can create
Columbia River have large tidal prisms and experi-
breaking bars. Therefore, the limiting depth over the
ence large waves. Charleston Harbor has a relatively
crest of the ebb shoal is expected to depend on both
large tidal prism, but experiences small waves as
the tidal prism and wave height as main forcing
compared to the other larger inlets and entrances
parameters. The depth over crest and will also
examined.
depend on geomorphologic factors such as grain size
Interpretation of the depth over the ebb-shoal crest
and sediment availability, inter-annual changes in the
on transects was verified by surface-area computation,
with each grid point representing 25 m2 at 5-m
hydrodynamic forcing, and other factors not dis-
cussed here.
spacing. The greater the surface area occupied by a
At Moriches Inlet, along the Long Island, NY,
particular depth of the ebb shoal, the more accurate
Atlantic coast and where the average annual wave
the measurement. Analysis of the tidal inlet data
height is 1.4 m and tidal prism 3.48 106 m3, the
revealed several functional relationships between the
limiting depth over the crest of the ebb shoal is 3.5
depth over the ebb-shoal crest and the tidal prism and
average annual significant wave height.
m MLLW. New Pass is located on the west coast of
Limiting (minimum) depth over ebb shoal crest
Florida, with mild wave climate and small tidal
was linearly regressed against the average annual
range. The ebb shoal exhibits temporal variability,
significant wave height (Fig. 8), resulting in the
oscillating between limiting depths of approximately
predictive equation:
1.25 and 2.5 m MLLW from 1994 through 1997. To
resolve the depth of the ebb-shoal crest across the
hC 0:27 3:6HS
MLLW
3
range of wave heights, the SHOALS data sets
(collected at low and medium wave energy coasts)
where hC is the depth over the ebb-shoal crest in
were supplemented with NOS data sets for Grays
meters relative to MLLW, and HS is the average-
Harbor, Columbia River Entrance, and Willapa Bay
Fig. 8. Linear regression between the depth over crest of an ebb shoal and average-annual significant wave height.
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