Similar to the Chesapeake Bay inlets studied by Byrne et al. (1980),
Goldsmith Inlet is small and located on a coast receiving limited longshore
sediment transport. Unlike the Chesapeake Bay inlets, however, Goldsmith Inlet
is protected by one jetty and comprises medium to coarse grain sediment.
Blockage of longshore sediment transport by the Goldsmith Inlet jetty and the
streaming of this material past the inlet mouth as discussed in Chapter 4 would
reduce sediment arrival to the inlet and, therefore, promote a larger channel
cross-sectional area.
For Goldsmith Inlet, the width-to-depth ratio, W/D = 32, based on
measurements listed in Table 6-6. The inlet channel is, therefore, less efficient
than the small Chesapeake Bay inlets studied by Byrne et al. (1980) where the
average W/D = 23. However, as compared to the larger inlets studied by Jarrett
(1976), it is highly hydraulically efficient.
Goldsmith Inlet ebb shoal
Goldsmith Inlet does not posses an ebb shoal, as discussed in Chapter 4.
Instead, a subaqueous spit is present eastward from the jetty, in the direction of
predominant eastward longshore transport. Longevity of the inlet is inferred to
owe in part to eastward migration and orientation of the inlet mouth, enabling
sediment that would otherwise be deposited in the entrance to bypass the inlet.
The bar crossing the mouth of Goldsmith Inlet is morphologically similar to a
spit growing from the large fillet that forms on the east side of the jetty. This
fillet receives sediment that is transported close to shore and around the jetty
from west to east.
A conventional ebb shoal is considered to form and be maintained as a
balance of the ebb current that transports sediment seaward and wave-induced
currents that transport sediment shoreward. For Goldsmith Inlet, the ebb current
is weak as compared to the flood current, and it is doubtful that it can sustain an
appreciable ebb shoal and sweep the channel clear of course sediment if the inlet
were stabilized to enter normal to the shoreline, parallel to the jetty. In addition,
the ebb discharge from Goldsmith Inlet is relatively small compared to the
volume of water moved by obliquely incident waves. Therefore, the ebb flow is
not adequate to maintain an ebb shoal. In migration of the inlet mouth to the
east, the ebb current issuing from the mouth of the inlet will tend to reinforce the
wave-induced longshore current directed to the east. Based on this interpretation,
the most stable configuration of Goldsmith Inlet is one with the channel directed
toward the east, not northward or parallel to the jetty.
Goldsmith Inlet flood shoal
The flood shoal at Goldsmith Inlet consists of three lobes that are located on
the east bank, west bank, and in the channel where the inlet channel enters
Goldsmith Pond (Figure 6-10). The volume of the flood shoal at Goldsmith Inlet
is estimated directly through bathymetry difference calculations in a GIS, after
Dean and Walton (1973) and using the empirical relation derived by Carr de
Betts (1999).
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Chapter 6 Inlet Morphology and Stability
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