best fit index curves for monochromatic waves previously presented by Goda 

 (1970) and chose the higher A-value to take into account the variability of 

 breaker heights. The lower value was chosen as two- thirds of the higher 

 value. Goda (1975) stated, "The choice was arbitrary, but it has yielded good 

 agreement with laboratory and field data." 



44. The relation of Goda (1975) was used by Seelig (1979) to develop 

 curves to estimate nearshore significant wave height over a range of beach 

 slopes and deepwater wave steepnesses. Seelig (1980) used Goda's relationship 

 to present curves to predict the location and magnitude of maximum wave height 

 in the surf zone . 



45. Thornton, Wu, and Guza (1985) introduced the term "mean breaker 

 line" for random waves, defined as the location where an averaged wave height 

 is maximum. Waves at the mean breaker line are both broken and unbroken. The 

 averaged wave height used was root-mean- square (rms) wave height H rms , maxi- 

 mum wave height !!„,„ , and the average of the highest one-third of the 

 recorded wave heights H 1/3 , also written as H s , the significant wave 

 height. Thornton, Wu, and Guza used field data acquired at Torrey Pines and 

 Santa Barbara, California, and laboratory data of Goda (1975); Seelig, Ahrens, 

 and Grosskopf (1983); and Thompson and Vincent (1984) to compare the analy- 

 tical model of Goda as calculated by Seelig with design curves based on 

 monochromatic waves given in the Shore Protection Manual (SPM) (1977) . The 

 model of Goda reasonably estimated H 1/3 and H,,,^ for large wave steepness 

 laboratory data, which was expected since the model was based on the same 

 laboratory data. The Goda model overpredicted H 1/3 for small wave steep- 

 nesses, but reasonably predicted H,,,^ . The depth at breaking was predicted 

 well for all data. The design curves in the SPM were found to be conserva- 

 tive, especially for small wave steepnesses. 



46. Sawaragi, Deguchi , and Park (1989) conducted an experiment with an 

 artificial reef placed in a small wave tank. The reef had a 1/30 slope that 

 extended above SWL and a 1/2 offshore slope. Sawaragi, Deguchi, and Park 

 developed an expression for the A-value of Equation 34 (Goda 1975) for wave 

 height over the reef, but the study concerned energy dissipation rather than 

 breaking wave properties . 



Summary 



47. Estimation of breaker height and location for irregular waves is 

 difficult, since breaking occurs at different locations with different 



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