extended northwards with time into the area of beach fill and, soon 

 after the completion of the jetty in spring 1966, the southern end of 

 Wrightsville Beach had accreted by approximately 30 to 40 meters. From 

 1968 until the end of the study period, the accretion fillet underwent 

 only minor changes with seasonal fluctuations of 15 to 25 meters. 

 Figure 23 shows typical excursion plots of WB47. 



The long-term excursion rate values for the entire beach are shown 

 in Table 7. The average erosion (excursion loss) per year along 

 Wrightsville Beach due to the rise in sea level is 0.10 meter (see 

 Table 6). This value must be subtracted from the measured excursion 

 rates to determine the average annual loss of beach excursion due 

 primarily to longshore processes. These values are shown in Table 7 and 

 are plotted in Figure 24. 



The average variation in seasonal excursion remained fairly constant 

 along the entire beach, with a maximum variation occurring at MLW and a 

 minimum at MHW. The difference in the seasonal excursions between 

 MLW-MSL and MHW-MSL gives an indication of the average change in beach- 

 face slope from winter to summer beach profiles. Table 8 gives the 

 average excursion values from 325 observations along Wrightsville Beach; 

 Figure 25 provides a visual interpretation of the relative change in 

 seasonal excursion distances. 



There were insufficient data points to quantify the response of 

 Wrightsville Beach to the 1965 and 1966 beach fills. However, 

 Figure 26 shows the semilog plots of the initial excursion loss after 

 the 1970 beach fill. These plots show the combined results from eight 

 profiles and are slightly different from Figure 20. The values of 

 excursion loss at time t after beach-fill placement have been normalized 

 by dividing them by the total initial excursion loss, £f£, and 

 hence, the results from many profiles can be combined to compute the 

 average exponential decay constant. Table 9 gives these values for the 

 MLW, MSL, and MHW contours, together with values of C> the proportion of 

 the MLW to MHW fill excursion which is lost due to sorting and slope 

 adjustment, the initial fill excursion, and the average long-term loss 

 rate. The relative differences in magnitude of the k values for the 

 three contours (shown in Table 9) indicate that the MSL contour eroded 

 faster, on the average, than either the MLW or MHW contours, thus 

 producing, as expected, a concave beach profile. The average long-term 

 excursion rate of -3.8 meters (erosion) per year for all three contours 

 indicates that once long-term slope readjustments occurred, the average 

 beach slope did not change from year to year. 



(b) Carolina Beach . Like Wrightsville Beach, three sections of 

 Carolina Beach (northern end, north-central, and southern half) were 

 affected differently by the action of the coastal processes from 1965 to 

 1975. 



The northern end extends from Carolina Beach Inlet southward for 

 1.5 kilometers to the 22-kilometer point (measured from the northern 



48 



