Results from the first year following inlet relocation have shown a shift in tidal flows from
Banks Channel to Mason Creek, with the new inlet acting as a sand trap due to the flood-
dominant tidal flows. The location of the inlet has been relatively stable with a small shift of the
channel centerline toward Wrightsville Beach. An increase in ebb flow through Mason Creek
would be expected to reduce interior shoaling and reduce southerly inlet migration. The design
channel geometries at Banks Channel and Mason Inlet should consider the information gathered
in this study in preparing for construction of the first inlet maintenance event. The tidal prism is
significantly greater in Mason Creek than through Banks Channel that, in concert with the
predominant flood over ebb tidal flows, contributes to shoaling rates observed at the inlet
entrance to Banks Channel and Mason Creek. Shoaling appears to have been greatest along the
southern 350 m of Banks Channel. resulting in a reduction in the overall tidal prism through this
channel.
The abandoned ebb shoal at the original inlet quickly collapsed and moved onshore. The ebb
shoal at the relocated inlet is presently symmetrical and growing rapidly. Within 5 years, the ebb
shoal is predicted to be at 90% equilibrium volume, and natural sand bypassing will be nearly
fully established.
ACKNOWLEDGEMENTS
The authors wish to thank Mr. David Weaver, Assistant County Manager to New Hanover
County, N.C. and Mr. David Kellam, Administrator of Figure Eight Island, N.C. for their
assistance and cooperation in this study. Also, we wish to acknowledge special assistance from
the U.S. Army Corps of Engineer District, Wilmington, NC, to Applied Technology and
Management, Inc., and Gahagan and Bryant, Inc. for sharing data and information. Permission
was granted to N.C. Kraus by Headquarters, U.S. Army Corps of Engineers, to publish this
information.
REFERENCES
Cleary, W. May, 1990. A Long Range Plan for Channel Maintenance and Beach Restoration,
Figure Eight Island, North Carolina (1984 to present). 4-20.
Erickson, K.M., Mason, T.P., and Goodrich, M. August, 2000. Environmental Assessment:
Mason Inlet Relocation Project. Final Report prepared for New Hanover County, NC, ATM
99-265, Ch. 2, 4-12.
Jarrett, J.T., 1977. Sediment Budget Analysis-Wrightsville Beach to Kure Beach, NC. GITI
Report 3, Department of the Army, Waterways Experiment Station, Vicksburg, MS, 55 pp.
Kana, T.W. 1989. Beach nourishment through inlet relocation. Proc. Beach Preservation
Technology '89, FSBPA, 293-302.
Kana, T.W., and Williams, T.L. 1985. Managing Shoreline Changes in the Presence of
Nearshore Shoal Migration and Attachment. Proc. Coastal Zone '85, ASCE, New York.
Kraus, N.C. 2000. Reservoir model of ebb-tidal shoal evolution and sand bypassing. J.
Waterway, Port, Coastal, and Ocean Eng., 126(6), 305-313.
U.S. Army Corps of Engineers Wilmington District. 1995. South Atlantic Division,
Environmental Assessment Channel Realignment Maintenance Dredging. Masonboro Inlet.
Walton, T.L., Jr., and Adams, W.D. 1976. Capacity of inlet outer bars to store sand. Proc. 15th
Coastal Eng. Conf., ASCE, 1,919-1,937.
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