In addition, Battjes (1974a) obtained the field measurements of 

 Dorrestein (1962) to verify his theory. Differences between measured and 

 calculated values for two separate cases when averaged over the surf zone 

 proved to be less than experimental error. It was concluded that the field 

 measurements lend support to the computational model. 



Goda's (1975) model for irregular waves is very similar except it uses 

 a varying probability function for the wave breaking criteria. It was 

 checked against experiments in a 30-meter basin with a 1:50 slope and a 

 water depth of 35 centimeters in the uniform end. Also on 1:10 slope where 

 the Hq = 50 centimeters in constant depth region. However, no comparison 

 of theory versus experimental results was presented by Goda (1975) for wave 

 setdown or setup . 



Finally, in support of the purely empirical relations for r\^ax (^^* ^^^^ 

 put forth by Hansen (1978a), Figure 55 presents the field data (black dots) 

 along with some measured or theoretical values. Generalizations for other 

 locations are pure speculation. 



K,,s ig- 



m w 



2.40 1 " ~ §- 



2.00 



1.60 



1.20 



1 n~~^7n — 



1/ w I 



7max=0,50-HBs 



0.20 0.40 Q60 OjSO 1.00 m T^max 0,20 0,^ 0,60 0,80 m ^max 



Figure 55. Empirical data for maximum wave setup (after Hansen, 1978), 



167 



