BARRIER ISLANDS
Barrier islands are one of the most
dynamic natural environments on
Earth. They are literally changing
every day.
In addition to movement caused
by longshore transport, they may
move seaward or landward because
of storm erosion and sea level falls
and rises. A barrier island moving
seaward is termed progradational.
Moving landward is retrogradational.
Natural landward migration is
termed island rollover. Rollover is
obvious on undeveloped islands
where sand is transported from the
beach to the marsh during storms.
Storm waves and surge breach the
dunes and deposit sand in an over-wash
fan on the landward side of
the island.
At Wrightsville Beach, the island’s
houses create a barrier to sand move-ment.
However, overwash fans and
landward migration are easily seen
on the undeveloped Masonboro and
Lea-Hutaff islands as well as at the
north end of Carolina Beach and on
Kure Beach in front of the North
Carolina Aquarium at Fort Fisher.
Yes, the beach is moving toward the
aquarium.
So as you lie on your towel, think
about the moving sands and the
changing landscape, and know that
the only constant on a barrier island
is change. But then return to the
beauty of sun, surf, and sand and
enjoy one of the golden treasures of
our region that should be cherished
and protected.
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www.wrightsvillebeachmagazine.com WBM
Roger Shew is a lecturer of geology and
environmental science at University of
North Carolina Wilmington. His back-ground
is in sedimentology, subsurface
methods (core, log, and geophysical
interpretation), resource geology (energy
and water), geoscience education,
and topics in sustainability. He is on
UNCW’s sustainability committee
and on the boards of Cape Fear River
Watch and the Cape Fear Conservation
Collaboration.