disposal site at the south end of Figure Eight Island across the narrowest section of the inlet
throat. Sediment excavated from Mason Creek and placed within the 12 acre, diked stockpile
area, provided the primary source of material for the inlet infill operations. An additional 57,400
m3 (75,000 yd3) of sediment excavated from the sand trap was hydraulically placed along the
oceanfront to construct a typical beach profile.
Fig. 5. Mason Inlet one week after inlet opening (photograph March 14, 2002).
Monitoring Plan
A comprehensive physical and biological monitoring program was formulated during the
design and permitting phases of the Project (Table 1) to determine the post-construction
shoreline changes, inlet maintenance dredging requirements, and water quality and
environmental resource impacts,. The monitoring program, (refer to Table 1) was to be
implemented by New Hanover County, North Carolina as an element of the Mason Inlet
Management Plan (MIMP), to address the Project's potential impact to the adjacent island
shoreline(s) position and the new inlet's maintenance dredging volumes and frequency. The
MIMP also established threshold shoreline and beach losses that will trigger maintenance
dredging and, or shoreline restoration events, and that could be performed under the
authorization granted by the Federal Section 404 Permit. This Plan requires video monitoring,
beach profile surveys, rectified aerial photographs, sand sampling, water quality sampling,
biological transects, benthic sampling and migratory and protected shorebird monitoring.
To augment the County's studies, the U.S. Army Corps of Engineers' Coastal Inlets Research
Program is supporting field studies to document development of the new ebb tidal shoal and to
monitor circulation changes within the 3 affected tidal channels of the estuary (Fig. 6). These
field investigations include periodic bathymetric surveys of the abandoned and new ebb-tidal
shoals, and of the entrance and inlet channels; beach profile surveys; and measurement of current
velocity and water surface elevation at three locations. Findings of these comprehensive
monitoring studies will provide valuable data and information to guide future maintenance
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