Table 6 

 Overtopping Adjustments * 













Swl 



Berm Elevation 



Relative Values 





ft 



ft, 



above NGVD 

 + 1.0 



cfs/ft 



Percent Change 



9.5 



0.798 



51 







+ 3.4 



0.409 





8.0 





+ 1.0 

 + 3.4 



0.326 

 0.102 



31 



7.0 





+ 1.0 

 + 3.4 



0.134 

 0.021 



16 



* Based on exponential curve averaged for hurricane data at 95 

 and 100 percent gain. 



were used because these represented the design conditions. Results are pre- 

 sented in the following section. 



Wind-Induced Overtopping 



39. The physical model results do not include the effects of local wind 

 on overtopping rates. Wind effects can cause an increase in wave energy 

 through wind-to-water energy transfers and thus higher runup and overtopping 

 through increased advection of spray over the structure. To establish a rela- 

 tion between wave-induced and wind-induced overtopping, several steps were 

 taken. A search of pertinent literature was conducted but no documented re- 

 search suitably addressed the computation of additional overtopping due to 

 wind. There were no published procedures which could be used to base a recom- 

 mendation for adjusting the Virginia Beach model results to include wind over- 

 topping other than the method described in the SPM (1984). However, other 

 attempts were made to determine relative values and perhaps provide insight 

 into wind-induced overtopping. 



40. As part of this study, CERC contracted Dr. Donald Resio of Offshore 

 and Coastal Technologies, Inc., who has conducted analytical studies for the 

 oil industry oa wind-Induced overtopping.* Dr. Reslo used video tapes of the 



* Unpublished report by Donald T. Resio (1987), "Assessment of Wind Effects 

 on Wave Overtopping of Proposed Virginia Beach Seawall," prepared for USAE 

 Waterways Experiment Station, Vicksburg, MS. 



27 



