Hedar (1965) suggested that the breaking process extends over a 

 distance equal to half the shallow-water wavelength. This wavelength is 

 based on the depth at this seaward position. On flat slopes, the resultant 

 height of a wave breaking against the structure varies only a small amount 

 with nearshore slope. A slope of 1 on 15 might increase the design break- 

 ing wave height by 20 to 80 percent depending on deepwater wavelength or 

 period. Galvin (1968,69) indicated a relationship between the distance 

 traveled by a plunging breaker and the wave height at breaking H^,. The 

 relationship between the breaker travel distance x^ and the breaker 

 height H^j depends on the nearshore slope and was expressed by Galvin 

 (1969) as: 



T Hy = (4.0 -9.25 m) Hj, 



(7-3) 



where m is the nearshore slope (ratio of vertical to horizontal distance) 

 and Tp = (4.0 - 9.25 ra) is the dimensionless plunge distance. (See 

 Figure 7-1.) 



Region where Breoking Starts 



Proposed Structur 



Breoking has not been Considered ) 



Wove Profile ot Start 

 of Breoking 



Wove Profile when Breaking 

 is Nearly Complete 



Figure 7-1. Definition of Breaker Geometry 



7-4 



