present numerical investigation, these differing recession values are attri- 
buted to the fact that storms of equal surge level result in varying volumes 
of erosion due to differences in total surge duration. In order to develop a 
single design curve descriptive of the overall relationship, an upper envelope 
line is provided for each plot. In each case, a small number of points lie 
above this line. These points were considered to be atypical in that they 
were found to result from generated storms of unusually long duration. 
165. The resulting straight line recession-recurrence interval rela- 
tionships for both hurricanes and northeasters were combined to produce a 
final single curve for each representative profile. This design curve was 
generated by adding the frequency of occurrence (reciprocal of the recurrence 
period) corresponding to a given envelope curve recession value for both the 
hurricanes and northeasters and taking the reciprocal of the sum to produce a 
return period for the combination. Both the individual storm simulations and 
the combined storm design curves are presented in the following analysis of 
existing condition profiles for the Sea Bright area. This procedure is not 
considered rigorous, but is believed to give a reasonable first-order 
estimate. 
166. Case A-Profile 160. The recession-recurrence interval curves 
corresponding to hurricanes and northeasters for Profile 160 are shown in 
Figures 31 and 32. The computed spread in recession values can readily be 
seen in each plot. As an example, one 400-year storm shown in Figure 31 indi- 
eates a recession of 67 ft. Analysis of the generated total surge shows that 
this event has a duration of 33.0 hr whereas the average generated surge dura- 
tion is on the order of 18-20 hr. For this reason, this point was allowed to 
fall outside the design envelope. The combined hurricane-northeaster design 
curve is shown in Figure 33. 
167. Case B-Profile 82. The recession-recurrence interval calculations 
for Profile 82 indicate that all storm events (both hurricanes and north- 
easters) result in erosion of the entire beach to the seawall. Although re- 
covery of the beach often follows a storm event, the present calculations are 
made for maximum recessions only. An implication of this analysis is that 
even a 10 to 20-year event could severely jeopardize the integrity of the 
seawall. The use of a smaller shape parameter, indicating a smaller grain 
size than first used, also resulted in complete erosion of the beach fronting 
the seawall. Since prediction of scour at the toe of a seawall is beyond the 
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