Figure 4. Kiawah’s northeast end shows the abundant vegetated beach ridges (foreground) and enormous volume of sand provided
by the Stono Inlet ebb-tidal delta. Waves breaking in the distance (top of photo) show the extent of the delta’s lobe.
(Photo by L. Sautter, 2008).
How do these related processes of tidal currents and
wave energies shape Kiawah Island? Kiawah is a northeast-
southwest trending barrier island of approximately 9.7 miles
in length. The island’s outline has a shape that Dr. Miles
Hayes likened to a drumstick, with the bulbous “meaty”
end (2.5 miles wide) near to Stono Inlet (Figure 3). Much of
the sand that comprises this bulbous end was transported
by waves from the inlet’s ebb-tidal delta to Kiawah’s beach.
Large sand bodies called swash bars periodically detach
from the delta and wave energy allows the sand to migrate
slowly landward and weld onto the downdrift beach. In some
cases, enough sand accretes so that the wind can form dunes
that subsequently become vegetated with sea oats and dune
grasses. These early plants are highly tolerant of the ocean’s
salty spray and help to anchor the dunes, forming vegetated
beach ridges (Figure 4).
Over long periods of time more swash bars detach from
the ebb-tidal delta and weld onto the downdrift beach. New
dunes build seaward of old dunes, and less salt-tolerant plant
species are then able to take hold in the partially protected
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environment of the second through fourth (or more) rows
of beach ridges. Eventually, the seaward accretion of the
shoreline thoroughly protects the oldest vegetated beach
ridges from the ocean’s salt spray, allowing live oaks to take
hold and thrive. Live oak and Palmetto trees establish what is
known as the maritime forest for our region. These two plants
are referred to as the climax species that no other vegetation
species in this environment can out-compete.
Longshore transport toward the southwest distributes
some of the ebb-tidal delta sand that was welded onto the
shore, providing abundant sand to Kiawah’s downdrift
beaches. Transported sand moves down the beach in the
zig-zag pattern described above, and eventually reaches a
barrier island’s downdrift inlet. Many sand grains enter the
inlet and are swept by tidal currents out to the inlet’s ebb-tidal
delta. Other grains, though, may be deposited at the island’s
terminus, at the edge of the inlet. This accretion allows the
island to “grow” in the downdrift direction, creating an
elongate feature known as a recurved spit (Figures 3 and 5).
The spit is analogous to a drumstick’s handle and often has
Naturally Kiawah