S a = specific gravity of an individual armor unit relative to the water in 

 which it is placed, S a = y a h w 

 cot a = reciprocal of breakwater slope, 1 .7 



thus obtaining 



K = 0.00 1495// 3 



Stability results for the three plans investigated can be summarized as follows: 



Plan 



H mo . ft* 



Stability Coefficient 



1A1 



<15.6 



<5.7 



1A2 



18.6 



9.6 



1A3 



15.6 



5.7 



* Lesser value of initial and repeat tests. 



Development of Improvement Plans 



A number of plans to improve stability of the existing structure were 

 considered. Those chosen for model testing included placing a submerged 

 breakwater 100-200 ft lakeward of the existing structure, attaching a berm 

 breakwater to the lakeside of the existing structure, and the addition of 18-ton 

 angular stone to the lakeside and/or harbor-side slope of the structure. 



Base Conditions 



In order to provide a baseline for comparing various improvement plans, 

 transmitted wave heights were measured for a range of wave conditions on the 

 existing structure. Results of these tests were as follows: 



r_, sec 



p 



Incident H mo . ft 



Transmitted H mo , ft 



swl 1 = 0.0 ft Iwd 



7.0 



2.3 



0.5 



7.0 



4.0 



0.7 



7.0 



6.7 



0.9 



7.0 



9.7 



1.2 



7.0 



11.7 



1.5 



7.0 



2.9 



0.7 



(Continued) 



swl = still-water level. 



12 



Chapter 3 Tests and Results 



