The relatively large tidal range and large sediment grain size contribute to
maintenance of inlet stability. Continual degradation of the jetty at Goldsmith
Inlet, which allows sediment to enter the inlet, acts to reduce inlet stability.
Channel migration between 1996 and 2002 is not known. It is inferred that
increasing rates of sediment bypassing around the jetty and close to shore, owing
to full impoundment on the west side and spit growth on the east side, promote
eastward migration of the inlet entrance. Migration of the channel creates an
increasingly sigmoidal or "S"-shaped configuration, which decreases the flushing
capacity of the inlet because of increasing length of channel and associated
increase in friction.
Table 4-6
Summary of Morphology Change at Goldsmith Inlet, 1955 to
Present
Date
Inlet entrance
Inlet channel
Inlet Exit
1955
--
Natural in-channel flood shoal --
1963 - 1964
Construction of jetty
--
1964
New work dredging New work dredging
New work dredging
Impoundment west
Natural flood shoal migration
of jetty and
Initial formation of present
1964 - 1972
associated erosion
east and west lobes
east of jetty
Initial formation of
spit east of jetty
Mature and stable east lobe
1972 - 1976
--
Assumed
acceleration of
sediment intrusion
Closure of Inlet
Closure of eastern natural
Continued flood shoal
1976 - 1980
(1980)
channel
growth
Assumed stability
through regular
Mature and stable west
dredging
lobe
1980 - 1990
--
Establishment of
Period of channel infilling
natural effective
begins
sediment bypassing
Continued spit
Development of attached west
development
bank shoal
Continued period of
1990 - 2002
channel infilling
Initial channel
Channel infilling in mid -
migration
channel
Rapid spit formation Inundation of Wetlands
Continued period of
2002 - 2003
presumably from raised
Rapid eastward
channel infilling
elevation of channel infilling
channel migration
Dredging and
April 2004
--
--
reorientation of inlet
202
Chapter 4 Morphology Change, and Channel Shoaling and Migration
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