man-influenced excursion rates. The plots (Figs. 11 to 14) are, in one 

 way, atypical of all profile plots taken along each beach because each 

 of these profiles has some data taken below MLW, whereas the majority of 

 profiles along the entire study area do not. This means that analysis 

 of contours below MLW is not worthwhile due to the paucity of data, and 

 that available data can result in misleading or questionable excursion 

 rates. Only Wrightsville and Carolina Beaches have high temporal 

 densities of data points for each MHW, MSL, and MLW contour and, 

 consequently, only plots from these beaches were redrawn at yet a larger 

 scale and analyzed. All large-scale plots for Wrightsville Beach and a 

 representative set from Carolina Beach are contained in Appendixes A and 

 B, respectively; all smaller scaled plots for Masonboro, Kure, and Fort 

 Fisher Beaches are in Appendixes C, D, and E, respectively. 



Historic events which may have affected the beach erosion-accretion 

 (excursion distance) are indicated on each excursion distance plot for 

 Wrightsville and Carolina Beaches (Figs. 16 and 17). A circle is placed 

 on a data point measured shortly after localized storm activity (see • 

 Table 5), and an arrow is placed at the approximate time beach fills 

 were completed. The same profiles in Figures 11 (WB15) and 12 (CB71) 

 are shown in Figures 16 and 17, respectively, drawn at the larger time 

 scale and with the historic events indicated. Excursion rates between 

 the beach fills (seasonally averaged response shown as a dashline) can 

 now be identified and quantified. Localized storms account for many of 

 the sudden losses in beach volume. However, some erosion (loss of 

 excursion distance) occurs at times other than those indicated in 

 Table 5, possibly due to localized storms of lesser magnitude, but 

 probably due to erosion from swell waves generated from distant storms. 



Sequential beach profiles taken between January 19 70 and December 

 1974 for profile WB15 are presented in Appendix F. These profiles are 

 presented to aid the reader in visualizing the postfill response of 

 Wrightsville Beach and thus to help interpret the results shown in 

 Figure 16. 



The following discussion outlines the general method of analysis 

 used on all excursion distance plots for Wrightsville and Carolina 

 Beaches. A schematic plot, similar to the MLW excursion distance plot 

 for WB15 (Fig. 16), is used as an example and is shown as Figure 18. 

 Section IV. 4 contains a beach-by-beach discussion and quantification 

 detailing the effect of natural and manmade influences on each. 



The three most prominent features exhibited by Figures 16 to 18 are: 

 (a) the long-term erosional-accretional trend is approximately constant 

 (linear) between beach-fill periods with minor fluctuations due to 

 seasonal storm-induced erosion and accretion cycles; (b) the placement 

 of a fill results in a sudden positive spike in the excursion distances; 

 and (c) immediately following a significant beach fill, loss of material 

 occurs at a rapid rate which gradually decreases to equal the long-term 

 recession rate. 



37 



