ERDC/CHL CHETN-II-47
March 2004
Figure 15. Nearshore geology of Folly Beach, SC, in relation to the three hot spots (courtesy of Paul
Gayes, Coastal Carolina University)
Tybee Island, GA. Tybee Island is located on the upper Georgia coast and has a long history of
beach fill, seawall and groin construction in response to shore front erosion. The latest Tybee Island
Shore Protection project consists of several project features including: construction of a north end
terminal groin, a south end terminal groin, an oceanfront beach fill, additional sand placed at the
island's south tip beach with t-head groin rehab, and a Back River groin field and beach fill to
mitigate for erosion on the back side of the island's southern tip. These components were completed
by July 2000.
One hot spot has formed on the ocean beach in the middle of the island (Figure 16). The suspected
cause of this hot spot is a change in shoreline orientation, which is also a nodal point for sediment
transport north into the Savannah River entrance and south to Tybee Creek (Back River) inlet. The
hot spot has become a sediment source for transport in both directions away from the placement
area. Methods taken to addressing the hot spot include the construction of groins at the hot spot area
to interfere with the longshore transport, lengthening and sand tightening of the north end groin to
trap sand from loss into the Savannah River entrance, increasing the beach's berm width and
increasing the frequency of renourishment to provide a sand supply to this nodal point.
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