excursion probably was larger than appears because only a few shoreline posi- 

 tions were measured. In over one-half the surveyed shore reach, the extreme 

 shoreline position change occurred between the first and last surveys, in- 

 dicating a relatively continuous shore retreat or advance. Because of this 

 trend, patterns shown in Figure 33 are similar to mean shoreline change rate 

 patterns shown in Figure 28. Areas of retreat are more numerous than areas 

 of advance. 

 Sound shoreline change rates 



81. 1850 to 1980. Shoreline changes on the sound side of the barrier 

 islands exhibit few consistencies in an alongshore direction (Figure 34) . 

 The largest retreat rates occurred in the Back Bay area, a constricted fresh- 

 water region reported to be free of inlets in historic time (Figure 9). 

 Accretionary trends adjacent to and south of Oregon Inlet appear to be inlet- 

 associated. The consistent 0.5- to 1.5-m/year retreat of the sound shore- 

 line south of Salvo, North Carolina, also occurs in an area where inlets 

 persistent in historic times have not been reported. Figure 35 illustrates 

 the standard deviation of shoreline position change in the sounds through 

 time. 



82. Partial study period. Figure 36 shows changes in the sound 

 shoreline for the same periods illustrated for the ocean shoreline in Fig- 

 ure 31. The 1852-1980-averaged sound shoreline change rate was -0.1 m/year, 

 a retreat which is 13 percent of the average retreat rate (-0.8 m/year) of 

 the ocean shore. 



83. In the sound adjacent to Oregon Inlet the standard deviation of 

 shoreline change (Figure 35) is very large, suggesting fluctuations that are 

 likely inlet-related. South of Rodanthe, the shoreline retreated in a rela- 

 tively continuous manner. Infrequent and severe storms probably caused the 

 changes in this area. However, the storm effects, which are usually localized 

 in time and location, were probably lost in spatial averaging, especially con- 

 sidering the large survey interval of this study. 



Oregon Inlet 



84. Oregon Inlet was opened in 1846 by a severe coastal storm. Ini- 

 tially, large quantities of water moved through New Inlet (Figure 9) into 

 Pamlico Sound. Precipitation and runoff further increased the volume of 

 water in the sound; when the wind direction changed to the west, some of this 

 ponded water was carried seaward north of the site of present-day Oregon Inlet 



71 



