widely varying wave conditions and, therefore, is an extremely useful tool 

 in the solution of many types of coastal engineering problems. 



When the refraction coefficient K r is determined, it is multiplied by the 

 shoaling coefficient K s to yield a conversion factor for transfer of deepwa- 

 ter wave heights to shallow-water values. The shoaling coefficient, a func- 

 tion of wave length and water depth, can be obtained from the Shore 

 Protection Manual (1984). 



Refraction and shoaling coefficients and shallow-water directions were 

 obtained at Noyo for various wave periods from five deepwater wave di- 

 rections (northwest counterclockwise through southwest) and are pre- 

 sented in Table 1. Shallow-water wave directions and refraction 

 coefficients represent an average of the values in the immediate vicinity 

 of the Noyo site (approximately the location of the wave generator in the 

 model). Shoaling coefficients were computed for an 81 -ft water depth 

 (75-ft pit elevation with 6-ft tide conditions superimposed) corresponding 

 to the simulated depth at the model wave generator. The wave-height ad- 

 justment factor K r x K s can be applied to any deepwater wave height to ob- 

 tain the corresponding shallow-water value. Based on the refracted 

 directions secured at the approximate locations of the wave generator in 

 the model for each wave period, the following test directions (deepwater 

 direction and corresponding shallow-water direction) were selected for 

 use during model testing. 



Deepwater Direction 

 deg 



Selected Shallow-Water Test Direction 

 deg 



Northwest, 315 



300 



West-northwest, 292.5 



288 



West, 270 



270 



West-southwest, 247.5 



254 



Southwest, 225 



238 



Prototype wave data and selection of test waves 



Measured prototype wave data on which a comprehensive statistical 

 analysis of wave conditions could be based were unavailable for the Noyo 

 Harbor area. However, statistical deepwater wave hindcast data represen- 

 tative of this area were obtained from the Sea-State Engineering Analysis 

 System (SEAS) by Corson (1985). Deepwater SEAS data are summarized 

 in Table 2. These data were converted to shallow-water values by applica- 

 tion of refraction and shoaling coefficients and are shown in Table 3. 

 Characteristics of test waves, wave period and significant wave height, 

 used in the model (selected from Table 3) are shown in the following 

 tabulation: 



Chapter 3 Tests Conditions and Procedures 



15 



