T [=] sec = T 



g [=] ft/sec^ = Lr^ 



where 



/ = structure freeboard defined as height of the seawall crest 

 above the swl 



b = beach freeboard defined as height of the beach at the base 

 of the seawall above the swl 



d = water depth at the flat bottom of the wave flume 



H = wave height defined as the monochromatic wave height at a 

 distance of 2,000 ft offshore (approximate location of wave 

 generator in model flume tests and the wave height on 

 which the physical model tests were based) 



T = wave period associated with the monochromatic wave 

 height H 



g = gravitational acceleration 



Dimensionless parameters that may also affect overtopping rates 

 include: 



cote 



d/dlOOO 



where 



cotG = cotangent of the beach slope defined as cotangent of the 

 slope from the base of the seawall to the swl 



^2000 = depth at a distance of 2,000 ft offshore 



Because the model profiles did not extend to the wave generator, there 

 was a difference in depth between the wave generator in the flume (ad- 

 justed for scale) and the actual depth offshore of Revere Beach. The ratio 

 d/d2000 is the ratio of the depth in the flume (adjusted for scale) to the 

 depth where the wave heights were determined from the numerical model. 

 Figures 8 through 12 show where the flume bottoms were fitted to the 

 beach profiles and illustrate the differences between depths in the flumes 

 and depths on the surveys at the location of the wave generator. Because 

 input wave information (wave height and period) was obtained from 

 SBEACH at the approximate location of the wave generator (approxi- 

 mately 2,000 ft offshore from the seawall), it was thought that the differ- 

 ence in depths, d/d2000, could play a role in defining the overtopping 



Chapter 3 Research Tasks A, B, and C 



31 



