4
Morphology Change, and
Channel Shoaling and
Migration
This chapter describes and quantifies morphology change at Mattituck Inlet
from 1891 to present and at Goldsmith Inlet from 1964 to present. For Mattituck
Inlet, change in the offshore and flood shoals, and in the inlet response to the
original navigation project and to subsequent modifications, is analyzed. For
Goldsmith Inlet, change in the channel, inlet orientation, and flood shoal is
analyzed.
Mattituck Inlet
To analyze morphology change for the offshore area at Mattituck Inlet, beach
profiles from the 6-8 October 2002 survey are compared to those from a March
1998 survey (OCTI 1998), spanning a 4-1/2 year interval. The long-term
morphology change of the offshore shoal associated with Mattituck Inlet is
analyzed by comparing a 1927 survey to the survey of 6-8 October 2002. For the
Mattituck Inlet navigation channel and flood shoal, morphology change and
response to jetty modifications is analyzed based upon historic aerial
photographs and data provided by the New York District.
Historic sounding data received from the New York District had been
archived on aperture cards, a form of media that requires a high-resolution
reader. The Hudson Blueprint Company was engaged to read the aperture cards.
Paper maps were produced and scanned in a large-format scanner, and the
resulting images were then calibrated, digitized, and converted into ArcView
shape files by means of Didger software.
Offshore morphology change
Beach profiles. Figures 4-1a to 4-1h plot the 1998 (OCTI 1998) and 2002
beach profile survey data for the offshore area west of Mattituck Inlet. Profile
transects were referenced to established monuments (OCTI 1998). Two
longshore bars can be identified on most of the profile lines, and cross-shore,
primarily seaward movement of the bars occurred between 1998 and 2002
(Figures 4-1e to 4-1h). More data sets are required over several years and with
greater frequency to determine the cause of movement as due to seasonal changes
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Chapter 4 Morphology Change, and Channel Shoaling and Migration
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