Figure 7 presents transmitted wave height as a function of incident wave 

 height. As would be expected, these data show larger transmitted wave 

 heights at the higher swl and at the longest wave period. 



Reef Breakwaters (Plans 2, 2A, 3, 4, 4A, and 4A1) 



This approach would use a reef breakwater of sufficient size to reduce 

 19-ft incident waves to about 13-ft waves in front of the existing structure. 

 The first reef structure tested, Plan 2 shown in Figure 8, was constructed to 

 an elevation of -20 ft lwd. It used a crown width of 72 ft, a stone weight of 

 5 tons, and was placed 150 ft lakeward of the existing structure. Testing with 

 various incident conditions produced the following results: 



T p . sec 



H mo , ft Measured 



c, 



Incident 



Behind Reef 



Behind Breakwater 



7.0 



2.3 



2.1 



0.5 



0.22 



7.0 



4.1 



3.7 



0.7 



0.17 



7.0 



6.1 



5.3 



0.9 



0.15 



7.0 



7.6 



6.6 



1.1 



0.14 



7.0 



10.2 



8.3 



1.4 



0.14 



7.0 



11.7 



9.4 



1.6 



0.14 



9.0 



2.8 



2.7 



0.7 



0.25 



9.0 



4.8 



4.4 



1.0 



0.21 



9.0 



7.0 



6.4 



1.3 



0.19 



9.0 



8.2 



7.3 



1.5 



0.18 



9.0 



9.4 



8.4 



1.7 



0.18 



11.6 



1.8 



1.6 



0.7 



0.39 



11.6 



3.9 



3.4 



1.1 



0.28 



11.6 



6.3 



5.3 



1.6 



0.25 



11.6 



8.6 



6.9 



2.0 



0.23 



11.6 



13.1 



10.0 



2.9 



0.22 



11.6 



16.8 



11.9 



4.1 



0.24 



11.6 



18.6 



13.0 



4.8 



0.26 



11.6 



19.8 



14.0 



5.4 



0.27 



The above data show that the chosen structure was successful in reducing a 

 19-ft incident wave to a height of slightly more than 13; however, maximum 

 transmitted heights, though somewhat reduced, still exceeded 1 ft at all 

 periods and 3 ft at the 11.6-sec period. Both the reef (Photo 20) and existing 

 breakwater (Photo 21) were completely stable. 



14 



