contrast, the eroded volume above the 1-m contour shows a much less rapid 

 increase. The Bruun fill experiences greater initial erosion during the early 

 stage of wave action, but also greater recovery in the post- storm period. 

 The volume of eroded material above the 0-depth contour does not show signifi- 

 cant increase during the storms, changing only from about 22 to 27 m 3 /m in the 

 case of berm erosion during the northeaster. Eroded volume above the 1-m 

 contour abruptly increases at the start of the storms, going from about 3 to 

 17 m 3 /m in the case of the berm and northeaster. The reason why the volume of 

 erosion above the 0-depth contour is relatively unchanged is that these 

 moderate storms primarily remove material from the upper portion of the 

 profile and redistribute it over the beach face, not transporting it far 

 offshore. 



The hurricane and northeaster produce about the same amount of erosion, 

 25-30 m 3 /m above the 0-depth contour and 13-16 m /m above the 1-m contour. 

 Eroded volumes above the 0-depth contour are comparable to those associated 

 with 2-5 year return period hurricanes and extratropical storms impacting the 

 mid-Atlantic coast (Birkemeier et al . 1987). The longer surge duration of the 

 northeaster was, therefore, approximately equivalent in erosion capacity to 

 the higher surge of the shorter duration hurricane. Time evolution of the 

 eroded volumes above the shoreline shows an approximate exponential approach 

 to an equilibrium value. These results are in general agreement with those 

 obtained by Kriebel and Dean (1985), who numerically examined eroded volume 

 and berm recession as a function of wave height, surge level, and other para- 

 meters . 

 Contours 



Figs. 10 and 11 plot the time evolution of the 0-depth and 1-m contours. 

 Decrease in magnitude of contour position indicates recession of the beach at 

 that contour. The 0-depth contours for both fills and both storms show 

 recession during pre-storm and storm periods, but begin to advance even before 

 the end of the storms and prior to arrival of the recovery waves, as the surge 

 subsides and the wave height decreases. The 1-m contour shows no recovery for 

 the berm because the subaerial dune/berm complex is steep, whereas the 0.5-m 

 contour for the Bruun fill does show some recovery since the gentler slope 



123 



