Empirical eigenf unction analysis has been used successfully to show 

 seasonal trends from beach profile data collected at Torrey Pines Beach, 

 California (Aubrey, 1979). A similar analysis applied to the Holden Beach 

 data set indicates a clear seasonal cycle in the first temporal demeaned 

 eigenf unction for only four (profile lines 8, 10, 12, and 16) of the pro- 

 file lines (Fig. 17) . 



Profile 

 line 16 



Profile 

 line 12 



Profile 

 line 10 



Profile 

 line 8 



1972 



YEAR 



Figure 17. Seasonal trend in selected beach profiles, shown 

 by the first temporal eigenf unction with the 

 mean removed. 



c. Short-Term Changes . 



(1) Dredging Operations . The Wilndngton District has performed 

 maintenance dredging along the Atlantic Intracoastal Waterway (AIW-J) for 

 a number of years. Holden Beach residents speculated that continued dredg- 

 ing in the Lockwoods Folly channel exacerbated the already severe erosion 

 problem at that end of the island. They argued that disposal of the mate- 

 rial on the mainland shore removed a source of sand which, under certain 

 conditions, protected or even nourished the island beach, so since 1967 

 the dredged material has been deposited along the east end of Holden Beach. 

 Dredging operations with material being pumped across the island and depos- 

 ited near profile line 2 are shown in the 19 71 aerial photo in Figure 2. 



Dredging records are incomplete for the BEP study period. Table 6 

 provides dredging dates with the available volumes either given or estimated. 

 There were other reported dredging periods when material was not deposited 

 on Holden Beach. 



37 



