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0.5 10 1.5 2 2.5 30 35 4.0 



Contour above MSI (m) 



Figure 28. Mean and standard deviation of unit volume changes by contour 

 for 17 selected storms at Atlantic City profile lines. 



is -100,000 cubic meters over the 5-kilometer study area compared to the gross 

 annual longshore transport rate of about 500,000 cubic meters (for the entire 

 littoral zone); this short-term beach erosion indicates that most of the sedi- 

 ment transport during storms is offshore. 



In Figure 29 the unit volume changes at each profile, as determined from 

 prestorm and poststorm survey data, are compared to the changes in MSL shore- 

 line position (0.0 contour) for the same storm data. In this way, volume 

 changes resulting in accretion and erosion are compared to shoreline changes 

 resulting in progression (advancement) and recession (retreat). Figure 30, 

 which depicts trends in volume change versus shoreline change for selected 

 storms, shows considerable differences between these two values, indicating, 

 at least during storms, that volume accretion is not necessarily accompanied 

 by MSL shoreline progression nor is volume erosion always accompanied by MSL 

 shoreline recession. These data demonstrate the need for caution when eval- 

 uating short-term beach changes from aerial photos. 



b. Beach-Fill Changes . Two major beach-fill projects at Atlantic City 

 during the BEP study (in 1963 and 1970) used a combination of stockpiling and 

 direct placement. Stockpiling entails periodically placing beach material at 

 a concentrated updrift location in the depleted area, and allowing natural 

 processes to move the fill downdrift to nourish the beach. Direct placement 

 involves placing the fill along the entire area to be nourished. 



As mentioned previously, the 1963 fill project consisted of 428,000 cubic 

 meters of fill placed between Oriental and Virginia Avenues to replenish the 

 greatly eroded beach resulting from the March 1962 storm. Figures 31 and 32 

 indicate the 1963 and 1970 beach-fill limits and the beach profiles before and 

 after both fills. Figure 33 shows the unit volume change from 1963 to 1972 

 for each profile line. These data indicate that the 1963 fill remained for 

 approximately 4 years on profile line 3 and provided nourishment to profile 

 lines 4 to 7 at later times as a result of natural processes, as indicated by 

 the dashline tracing volume increases along the profile lines. However, those 

 same natural processes caused a continued erosion problem that required the 



35 



