Wave-height experiments for the initial improvement plans (Plans 1-8) indi- 

 ated that Plan 8 provided slightly better wave protection to the harbor than the 

 other plans. For typical storm-wave conditions, wave heights in the harbor for 

 Plan 8 were 0.03 to 0.21 m (0.1 to 0.7 ft) less than the other improvement plans; 

 and for extreme storm-wave conditions, from 0.06 to 0.30 m (0.2 to 1.0 ft) less 

 than the other plans. An evaluation of the sediment-tracer experiments, however, 

 revealed that Plan 8 resulted in significantly more shoaling in the harbor entrance 

 relative to the other plans. The breakwater configurations of Plans 3, 4, 6, and 7 

 experienced essentially no shoaling of the harbor entrance. An evaluation of wave 

 conditions in the harbor for these plans indicated that Plans 6 and 7 provided 

 greater wave protection than Plans 3 and 4. Therefore, the breakwater configura- 

 tions of Plans 6 and 7 were considered optimum at this point with respect to wave 

 conditions in the harbor and the prevention of shoaling in the entrance channel. 

 Based on model results, these breakwater layouts were used as a basis for 

 subsequent experiments. 



The breakwater layouts of Plans 9 and 10 were similar to those of Plans 7 and 

 6, respectively; but a portion of the existing north breakwater was removed, and 

 the depths were reduced on the harbor side of the new structure. A comparison of 

 wave heights obtained for Plans 9 and 10 revealed that the results were similar. In 

 some instances, the Plan 9 breakwater configuration resulted in slightly larger 

 wave heights at a particular location in the harbor; and in some cases, the Plan 10 

 layout resulted in slightly larger values. A comparison of wave heights obtained 

 for Plans 9 and 10 with those of existing conditions indicated, however, that both 

 plans significantly reduced wave heights in the harbor. The Plan 9 breakwater 

 configuraion resulted in wave-height reductions ranging from 31 to 71 percent in 

 the harbor considering all hydrodynamic conditions; and the Plan 10 breakwater 

 resulted in reductions ranging from 34 to 67 percent. 



Sediment-tracer experiments for Plans 9 and 10 revealed similar patterns and 

 subsequent deposits for waves from 1 1 deg with both no flow and riverflow 

 conditions. Waves from 59 deg revealed similar patterns and deposits for no flow 

 conditions; however, with riverflow conditions, slight deposits occurred in the 

 harbor entrance for Plan 10. These results indicate that the Plan 9 breakwater 

 configuration will provide slightly more shoaling protection of the harbor entrance 

 than that of Plan 10. Both plans, however, are a significant improvement over 

 existing conditions, which shoal for every experimental series. 



Wave-induced current patterns and magnitudes for Plans 9 and 10 revealed 

 similar results, with currents moving southerly along the shoreline and past the 

 harbor. Weak eddies also formed at the harbor entrance. The breakwaters of 

 Plans 9 and 10 deflected currents slightly lakeward as they passed the harbor 

 versus those of existing conditions. Once past the harbor, currents moved 

 southerly along the shoreline for all situations. 



A comparison of wave heights in the harbor as a result of boat wakes 

 indicated that Plan 9 would result in slightly smaller values than Plan 10 for the 

 27- and 30-m-long (90- and 100-ft-long) vessels. For the 183- and 210-m-long 

 (600- and 630-ft-long) vessels, wave heights in the harbor were similar. A 

 comparison of boat wakes for the Plans 9 and 10 layouts with existing conditions 



Chapter 6 Physical Model 59 



