PROFILE VIEWS 



RELATIVE FREEBOARD, F' 



Figure 20. Comparison of overtopping trend curves for the Roughans 

 Point seawall with no revetment (configuration RP-1) and the same 

 seawall fronted by a standard riprap revetment (configuration RP-2) 



profile would provide a major discontinuity at the wall to disrupt the wave 

 action and runup flow and still allow the recurve to be effective. It was 

 also felt that it would be better to build the revetment more like a wave 

 absorber rather than using the standard riprap revetment design. The absorber 

 revetment design would use additional armor stone out near the toe to trip the 

 waves and dissipate the energy as far offshore as possible. These concepts 

 led to the design of a wide berm profile wave absorber revetment. 

 Berms 



26. The performance of the wide berm absorber revetment (configura- 

 tion 4) in reducing wave overtopping of the seawall can be compared to the 

 overtopping trends for a seawall fronted by a traditional riprap revetment 

 (configuration 2) in Figure 21. Over most of the range of interest, as indi- 

 cated, the wide berm configuration is better than the standard riprap revet- 

 ment. The influence of a berm is noted also in discussion of the influence of 

 extensive toe protection used for the Cape Hatteras vertical wall configuration 

 and demonstrated by the data shown in Figure 19. In general, it appears that 



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