5 Conclusions 



Based on the results of the hydraulic model investigation reported 

 herein, it is concluded that: 



a. Existing conditions are characterized by rough and turbulent wave 

 conditions in the Noyo River entrance. Maximum wave heights 

 ranged from 8.5 to 13.7 ft in the entrance for operational conditions 

 (incident waves with heights of 14 ft or less) and from 12.2 to 

 15.2 ft for extreme conditions (waves up to 32 ft in height), 

 depending on incident wave direction. 



b. The offshore breakwater plan will result in maximum wave heights 

 ranging from 6.3 to 9.3 ft in the entrance for operational wave 

 conditions and 8.7 to 14.6 ft for extreme conditions, depending on 

 incident wave direction. 



c. The offshore breakwater plan will not meet the 6.0-ft wave-height 

 criterion in the entrance for all incident waves of 14 ft or less 

 (operational conditions). Based on hindcast data, however, the 

 breakwater plan will result in the criterion being achieved 37 percent 

 more of the time than it currently is for existing conditions when 

 operational waves are present. This is equivalent to an average of 

 23.5 days per year. The magnitude of the average wave height in 

 the jettied entrance will be decreased by about 27 percent as a result 

 of the offshore breakwater for operational waves. 



d. With no waves present, the offshore breakwater resulted in riverine 

 sediment patterns similar to those obtained for existing conditions 

 except for the 100-year (41,000 cfs) discharge. For this condition, 

 the breakwater prevented material from moving as far seaward in 

 the cove as it did under existing conditions. 



e. With waves present from west-northwest and west, the offshore 

 breakwater slightly changes the paths of migration and subsequent 

 deposits for some river discharges and does not for others. In 

 general, considering all test conditions, riverine sediment will 

 deposit in an area in the cove between the existing jettied entrance 



Chapter 5 Conclusions 



27 



