the Delaware shoreline retreat rate is computed as 5.3 feet per year, nearly 

 the same as the 25-year (1949-74) value from Ludlam Beach. 



d. Sea Level Rise Changes . Using tide gage records and coastal survey 

 data obtained near Atlantic City from 1920 to 1970, Hicks (1972) determined 

 sea level has been rising at a rate of 0.0146 foot per year (about 1.5 feet 

 per century). On Ludlam Beach where the slope varies between 0.02 and 0.036 

 and averages 0.03 (Fig. 26), sea level rise will cause a shoreline retreat of 

 between 0.7 and 0.4 foot per year, averaging 0.5 foot per year or approximately 

 one-tenth of the 25-year rate indicated. These rates neglect any readjustment 

 of the profile to sea level rise. 



4. Volume Changes . 



Cumulative changes in sand volume per lineal foot of beach above MSL are 

 plotted in Appendix D. Four frequencies of beach volume change are identified 

 in the survey data in Appendix D: (a) Changes caused by events (e.g., storms) 

 between successive surveys, (b) monthly changes, (c) yearly changes, and (d) 

 net changes over the 10-year study period. 



a. Storm Changes . Seven storms occurred during the 1962-72 period for 

 which poststorm surveys were available. The survey and storm dates, and the 

 average MSL shoreline change and average volume change between surveys for 

 each storm, are given in Table 6. MSL shoreline changes and volume changes 

 for each storm by profile line are given in Figures 30 and 31. When weighted 

 by the distance between profile lines, the average sand loss for the entire 

 Ludlam Beach shore (2.3 cubic yards per lineal foot of beach) was 80,000 cubic 

 yards per storm. The most severe storm loss occurred in March 1969; 4.6 cubic 

 yards per foot, or a total 160,000 cubic yards, of Ludlam Beach sand was re- 

 moved from above MSL. The average shoreline retreat resulting from this storm 

 was 46.6 feet. Due to the rapid rate at which beach profiles have been observed 

 to recover from storm erosion (e.g., DeWall, Pritchett, and Galvin, 1977; 

 Birkemeier, 1979), these losses may be considered conservative estimates! 



Table 6. Average shoreline and beach volume change for seven 

 storms at Ludlam Beach. 



Storm date 







Survey 



dates 





MSL 

 change 



Unit volume 

 change 





Befc 



re 



After 

















(ft)^ 



(ydVft) ^ 



7-8 Nov. 



1963 



30 



Oct. 



1963 



14 Nov. 



1963 



+ 1.5 



-1.5 



12-14 Sept. 



1964 



29 



Aug. 



1964 



23 Sept 



1964 



+24.5 



-1.5 



22-23 Jan. 



1969 



14 



Jan. 



1969 



11 Feb. 



1969 



-3.9 



-2.8 



1-2 Mar. 



1969 



11 



Feb. 



1969 



14 Mar. 



1969 



-46.6 



-4.6 



17 Dec. 



1970 



9 



Dec. 



1970 



20 Dec. 



1970 



-9.2 



-2.4 



4 Feb. 



1972 



11 



Jan. 



1972 



16 Feb. 



1972 



+ 14.0 



-1.7 



19 Feb. 



1972 



16 



Feb, 



1972 



24 Feb. 



1972 



-5.0 



-1.4 



^Distance-weighted values 



42 



