shoreline change rates. The arcuate strand has relatively few 

 inlets . 



Dramatic alongshore changes in the shoreline occurred in the 

 vicinity of inlets. Inlet formation and migration and changes 

 in inlet ebb- tidal delta morphology not only affect cross- 

 shore position of the shoreline, but also control growth and 

 decay of spits and barriers in an alongshore direction. 

 Changes in inlet width of over 1,000 m and aerial changes on 

 the order of 110,000 m 2 /year to adjacent spits were observed. 

 Temporal examination of alongshore changes at inlets suggests 

 they result from continuous changes in inlet and ebb delta 

 morphology driven by changes in environmental factors such as 

 reversals in drift direction. 



Shoreline change rates have varied greatly from one period to 

 another. Some segments of shoreline are temporally consistent 

 in change direction, but most alternate between periods of 

 erosion and accretion. Through 130 years of survey data, net 

 change has been in favor of erosion. Temporal variations and 

 difficulties encountered in trying to account for them prevent 

 accurate quantitative forecasts of shoreline change decades 

 into the future . 



The east-west oriented arcuate strand geomorphic zone, extend- 

 ing from North Inlet to Cape Fear River, is the most stable 

 shoreline examined. Approximately 87 percent of this shore- 

 line has changed ±1 m/year or less over the duration of survey 

 data. The remaining shoreline is divided equally between ero- 

 sion and accretion in excess of ±1 m/year. 



Bull Bay, which is protected in several ways from a full range 

 of wave conditions experienced by the rest of the coast, has a 

 stable shoreline. Approximately 82 percent of Bull Bay has 

 changed ±1 m/year or less over the duration of survey data. 

 The most sheltered segments of shoreline (4 percent) have 

 accreted more than 1 m/year, and shoreline open to waves from 

 the northeast (14 percent) has been eroding in excess of 

 1 m/year. 



Segments of shoreline predominantly showing erosion (more than 

 50 percent of shoreline is eroding greater than 1 m/year) were 

 the barrier island shoreline between Tybee Island and 

 St. Helena Sound, the cuspate delta geomorphic zone centered 

 around the Santee River delta, and north of Cape Fear. 

 Although no correlation was evident between shoreline orienta- 

 tion and shoreline change, these three reaches are the most 

 north- south oriented reaches in the study area. Examination 

 of wave data suggested north- south shoreline segments received 

 highest percentages of swell waves. 



The only segment of shoreline in which accretion (greater than 

 1 m/year) dominated was between Charleston Harbor and Bull 

 Bay. Approximately 45 percent of this shoreline was accret- 

 ing, while 30 percent was eroding and 25 percent changed 

 ±1 m/year or less. The dominance of accretion in this area is 



146 



