PART V: PRESENT AND FUTURE SHORELINE CHANGES 

 Analysis of Present Shoreline Positions 



167. The shoreline is defined by the zone of intersection of land, sea, 

 and air. Shoreline position at any point in time is a function of complex 

 interaction of five principal factors: sea level, sea energy, sediment sup- 

 ply, geology, and human involvement. These factors operate over very short to 

 very long time scales . Sea level includes daily tides , surges , annual tide 

 variations, climate and geologically controlled water-level changes, and other 

 naturally produced changes to ocean water levels. Little opportunity was 

 available to evaluate sea level effects within the study area beyond what has 

 already been discussed in previous sections. Sea energy is manifested in 

 waves and currents that reach the shoreline. The WIS data were used to 

 examine waves as a factor in controlling shoreline position. Previous 

 research described in Part II indicates most sediment for South Carolina's 

 beaches comes from exhumed pre-Holocene coastal sediments. No quantifiable 

 data exist on sediment supply reaching beaches to allow evaluation of this 

 factor as a control on shoreline position. Nearshore shelf bathymetry, depth 

 to pre-Holocene semiconsolidated sediments, and antecedent topography are 

 geological influences on shoreline position. A brief evaluation of bathymetry 

 and depth to pre-Holocene sediment was conducted in the study area. Human 

 intervention has affected shoreline position in several locations within the 

 study area. At most locations of human intervention, time frames for 

 intervention have been short. However, at Charleston Harbor and Winyah Bay, 

 humans have had an impact for roughly two -thirds of the time embraced by this 

 study. Effects of this intervention on the coastline at Morris Island, South 

 Island, and other locations have been described previously in the shoreline 

 change data analysis. 



168. To compare large amounts of shoreline data generated in this anal- 

 ysis to shoreline orientation, bathymetry, and depth to pre-Holocene material, 

 data were summarized for 282 coastal segments defined in the original mapping 

 procedure (Figures 22a and b) . A summary of shoreline change for each section 

 of each map is included in Appendix A. Since original selection of segments 

 was based solely on the straightness of shoreline and not directly on its 

 erosion/accretion history, the following results can be considered only 



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