PART VII: CONCLUSION 



54. Using the STHM and a minimum beach elevation of +3.4 ft NGVD, it 

 appears the Phase II seawall design will reduce overtopping rates and volumes 

 to a suitable level as determined by NAO. Calculated values show that with 

 the beach elevation held at +1.0 ft NGVD, overtopping rates increase signifi- 

 cantly. However, adjusted values for the shallower beach elevation show that 

 under the design storm events much lower overtopping rates are expected. The 

 lower overtopping rates can be assured only if the beach is well maintained 

 through the life of the project. Since these overtopping rates are for gen- 

 eral conditions, there could be localized areas that experience higher or 

 lower overtopping rates due to the two-dimensional nature of the physical 

 model which cannot consider three-dimensional effects such as wave focusing, 

 divergence, or bathymetry variations along the length of the study area. It 

 is also difficult to predict the degree to which wind-induced overtopping will 

 affect the total volume and peak rates during a storm. 



55. The most critical time for the project would be after the passage 

 of more than one significant storm between renourishment intervals. The beach 

 would be in an eroded state which makes the seawall more susceptible to storm- 

 induced overtopping. Proper and prompt maintenance of the beach template 

 after erosion events is critical for effective project performance. 



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