/. The breakwater configuration of Plan 43 will result in improved surge 

 conditions due to long-period wave energy in Noyo River and Harbor. 



g. The breakwater configuration of Plan 43 will not interfere with the 

 movement of riverine sediment seaward into Noyo Cove; however, 

 the structure will direct sediment to the northern portion of the cove. 



The Noyo River and Harbor model was reactivated to determine the op- 

 timum breakwater plan that would provide the fishing fleet protection 

 from hazardous wave conditions while traveling through the jettied en- 

 trance. The breakwater plan was developed for 14-ft design waves, as op- 

 posed to waves up to 32 ft in the initial study. During storm conditions 

 above a certain threshold (approximately 14-ft waves) fishermen presum- 

 ably do not go out to fish; therefore, there are fewer benefits for protect- 

 ing the entrance under these extreme conditions. Most benefits would be 

 derived for wave conditions with heights of 14 ft or less. Details of the 

 supplement tests were published in Bottin and Mize (1989). Conclusions 

 based on results of these tests are listed below. Plan numbers refer to the 

 supplemental investigation. 



a. Existing conditions are characterized by very rough and turbulent 

 wave conditions in the Noyo River jettied entrance for 15-sec, 14-ft 

 incident design wave conditions. Waves with maximum heights 

 ranging from 9.3 to 11.7 ft will occur in the entrance, depending on 

 direction of wave approach. 



b. Of the test plans involving a shore-connected outer north breakwater 

 and a detached inner breakwater (Plans 1 through 14), Plan 14 

 (300-ft-long outer and 250-ft-long inner breakwaters) will meet the 

 established 6.0-ft wave-height criterion in the existing entrance for 

 design wave conditions from all directions. Wave heights in the 

 entrance for waves from the predominant west-northwest direction will 

 be 3.5 ft or less. 



c. Incremental removal of the Plan 14 outer breakwater (Plans 27 

 through 31) indicated that the 250-ft-long inner breakwater alone 

 (Plan 31) would meet the established criterion for design wave 

 conditions from all directions. Wave heights up to 5.8 ft will exist 

 in the entrance for waves from the predominant west-northwest 

 direction. 



d. Neither the outer shore-connected north breakwater and outer 

 detached south breakwater (Plan 15) nor the outer detached south 

 breakwater plans (Plans 16 through 18) will meet the established 

 wave-height criterion for design wave conditions. Maximum wave 

 heights will range from 7.4 to 1 1.2 ft in the existing entrance for 

 these plans. 



e. Of the improvement plans involving a curved breakwater seaward of 

 the existing entrance (Plans 19 through 22), the 450-ft-long 



Chapter 1 Introduction 



