Along the North Carolina, South Carolina, and Georgia coasts
the variability in the coastal vulnerability index (CVI) ranking (Figure 8) is more strongly influenced by different variables than the New York - New Jersey coast. Here,
geomorphology is still the dominant variable (Figure 9). Variations in the CVI, however,are apparent due to the rate of relative sea-level change and wave
height. The rate of sea-level change
(Figure 10) is lowest at Cape Fear, North Carolina, due to
long-term tectonic uplift of the mid-Carolina Platform High, also
known as the Cape Fear Arch (Gohn, 1988). This factor places the
risk due to sea-level rise for Cape Fear into the moderate category
when other risk variables would give it a higher risk.
The risk due to wave height varies between the north and south
sides of Cape Hatteras and Cape Lookout (Figure 11), and generally decreases from
Cape Hatteras southward into the Georgia embayment. This reflects
differences in wave energy at two spatial scales. At the scale of
each cape, there is a substantial difference in wave energy between
the east-facing (high energy) and south-facing (lower energy) cape
flanks. This is due in part to the orientation of the shoreline
relative to the open Atlantic Ocean, and in part to the sheltering
effect of the large sand shoals that extend several kilometers
southeast from each cape (Heron et al., 1984). The decrease in wave
energy from Cape Hatteras to Georgia is due primarily to the
increasing continental shelf width in this region.
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