sorting. These decreased depths provide an added measure of protection 

 to the beach by forcing waves to break farther offshore. Individual 

 designs of, and the nature of the sediment used in each beach fill, 

 dictate the degree to which these factors benefit the beach area. 

 Consequently, they will not be further addressed in this analysis, but 

 must be kept in mind when dealing with the design or evaluation of a 

 beach fill. 



An interesting feature of Figure 20 is the relative magnitude of the 

 k values (the decay rate) of the MLW, MSL, and MHW curves. The greater 

 the k value, the faster the rate of initial loss (erosion). Conse- 

 quently, the results show that the MHW contour eroded at a faster rate 

 than the MSL contour, which in turn eroded at a faster rate than the MLW 

 contour. In other words, the slope of the beach face readjusted itself 

 and became less steep during the initial loss period. 



4. Beach Behavior from 1965 to 1975. 



(a) Wrightsville Beach. The behavior of Wrightsville Beach in 

 response to coastal processes during the 1965 to 1975 decade is best 

 described by conveniently dividing Wrightsville Beach into three 

 sections — the northern, central, and southern sections. 



The northern section can be characterized as a slowly accreting 

 beach with the rate of accretion falling from a maximum of 1.8 meters 

 per year at Mason Inlet to near zero about 1.75 kilometers farther 

 south. Figure 21 shows the excursion plots for WB3 ■, typical of the 

 beach behavior in this northern section. Superimposed upon the average 

 accreting excursion is a seasonal variation of approximately 20 meters. 

 The minimum excursion distances occur during the first three (winter) 

 months of the year and the maximum from July to September. Figure 21 

 shows that the beach in this section is able to respond to storms, 

 particularly noted are those in February and March of 1973, and to 

 rebuild itself without artificial renourishment. 



Between the points 1.75 and 5 kilometers, the central section of 

 Wrightsville Beach has been eroding constantly since 1965. The excur- 

 sion plots for WB16 (Fig. 22) are typical of the area of maximum erosion 

 experienced around the northern area of the town of Wrightsville Beach. 

 Beach fills in 1965, 1966, and 1970 were placed to protect this town; 

 however, the continued high erosion rate nullified those efforts. The 

 data are too sparse to obtain seasonal variations before 1970, but since 

 that time the seasonal excursion within the central section was 

 approximately 25 meters. 



The behavior of the southern 1.5-kilometer section of Wrightsville 

 Beach has been dominated by the construction of the northern jetty on 

 Masonboro Inlet. During the first 4 months in 1966 (prior to the 1966 

 beach fill), the nearshore zone of the beach immediately north of the 

 nearly -completed jetty accreted by up to 40 meters, especially the MLW 

 and MWL contours of profiles WB49 and WB50. This accretion fillet 



45 



