Figures 4-47a through 4-47e plot morphology change within the midchannel
area, migration of the intact portion of the natural in-channel flood shoal, and
eventual closure of the eastern, natural channel. The fact that a dry portion of the
natural flood shoal was left intact may have greatly influenced evolution of the
channel and the present-day flood shoal at Goldsmith Inlet. The continued
existence of the dry portion of the natural flood shoal created two channels that
begin 450 ft into the inlet (Figures 4-47a and 4-47b). The western, modified
channel, as well as the initial 450 ft, would be considerably deeper than the
eastern natural channel. During flood tide, gravel and coarse sediment would,
therefore, tend to accumulate within the modified channel.
The sediment that constituted the portion of the natural flood shoal that was
left intact appears to have been redistributed by tidal currents during the time
period considered. Intrusion of new sediment resulted in the eventual closure of
the eastern natural channel and the apparent creation of new wetland along the
east bank (Figures 4-47c through 4-47e).
An attached shoal developed along the west bank and is illustrated in
Figures 4-47c and 4-47e. The evolution of this attached shoal resulted in an
increasingly sigmoidal channel morphology, which modifies the ebb and flood
current (and resulting sediment deposition). Initial growth of this attached shoal
could be discerned in 1976, and no growth was apparent in 1980 and 1993
(Figures 4-47c and 4-47d). The apparent absence of this attached shoal may be
attributable to the aerial photographs for this period being taken at a time of
higher water. It is also possible, however, that this attached shoal had been
dredged. This attached shoal is observed to have grown rapidly in recent years,
indicating increased sediment deposition within the channel (Figure 4-47e).
The location and areal morphology of the flood shoal for the time period
considered is illustrated in Figures 4-48a through 4-48d, referenced against the
present shoreline (15 April 2004). The photographs of 28 April 1969 and
24 May 1980 appear to have been taken at higher water, when only small
portions of the submerged flood shoal were discernible, and are not shown.
Because the extent of the flood shoal that is visible depends on several factors,
particularly water level, values obtained are approximations. They do, however,
indicate trends of movement and growth of the flood shoal at Goldsmith Inlet.
New work modifications introduced to Goldsmith Inlet resulted in the
migration of the natural flood shoal along the east bank. The sediment that
composed this feature apparently relocated to the eastern bank, where the inlet
empties into Goldsmith Pond. This sediment apparently began the formation of
the eastern lobe of the present-day flood shoal (Figures 4-48a and 4-48b).
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Chapter 4 Morphology Change, and Channel Shoaling and Migration
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