

1.3 





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'50.4exp(-}3.S7F') 







- 



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 m 



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RELATIVE FREEBOARO. F' = 



\ mo p/ 



Figure 10. Q versus F' for Phase II seawall 



Interactions, or various runup effects caused by the complex seawall geometry 

 for the various swl's. 



37. The RFM did provide a predictive tool for estimating overtopping 

 rates with the beach elevation at 3.4 ft above NGVD. NAO requested calcula- 

 tions of overtopping rates, using existing model data, for a bottom elevation 

 of 3.4 ft above NGVD in front of the seawall instead of the +1.0 ft elevation 

 which was tested. Because time requirements prohibited modification of the 

 physical model and additional testing, CERC performed an analysis which meshed 

 the RFM and the STHM to compute these overtopping estimates. 



38. The RFM was used to estimate an overtopping rate for a shallower 

 water depth based on its exponential curve. This new value for overtopping 

 was compared to an average overtopping measured from the model tests with 

 deeper water levels (bottom elevation of +3.4 NGVD as opposed to +1.0 NGVD). 

 The percent reduction in average overtopping was computed for each of the 

 three design water levels. These values are shown in Table 6. The percent 

 reductions were then multiplied against the physical model results, and the 

 STHM was again applied. Only the hurricane data at 95 and 100 percent gain 



26 



