was placed around the east end of the plan 6 breakwater and around the 

 end of the east channel pier to break up reflecting and diffracting waves 

 around those structures. Additional stones were placed around the west 

 end of the breakwater and around the end of the west channel pier for 

 plan 6B. (Fig. 4-23.) 



5^ Plan 7 . This plan consisted of one 608-foot-long 

 breakwater located approximately perpendicular to the entrance channel 

 centerline and 200 feet lakeward from the outer end of the east channel 

 pier (Fig. 4-24). 



6^ Plans 7A and 7B . These plans involved variations 

 in the elements of plan 7. For plan 7A, three breakwater cells and 

 connecting sections were added to the west end of the plan 7 structure. 

 For plan 7B, one of these cells was removed, and the other two were 

 angled 30° toward the south. (Fig. 4-24.) 



(j) Summary of Test Results . 



1^ Under existing conditions, Vermilion Harbor is ex- 

 posed to severe wave attack from all directions clockwise from west to 

 northeast. Resulting wave heights in the harbor area are of such magni- 

 tude as to severely restrict the use of the harbor and boat-mooring 

 lagoons. 



2_ The most severe wave conditions in the harbor area 

 are caused by storm waves approaching from the north to northeast 

 directions. 



3 The proposed plan of improvement (plan 1) will not 

 provide sufficient protection for full use of the harbor. 



4 Either plan 7A or 78 will provide the protection 

 desired from wave action at the entrance to the river channel, up the 

 channel, and in the entrances to the boat-mooring lagoons; however, 

 since plan 7B uses one less cellular unit it should be more economical 

 to construct. 



b. Harbor Wave and Surge Action Studies; Intermediate- and Long- 

 Period Waves; and Undistorted- and Distorted-Scale Models . (Since the 

 need for model studies concerning tsunamis is rare and little is known 

 about the methods of modeling this complicated phenomenon, the descrip- 

 tion of a tsunami model is omitted. However, seiche and tsunami models 

 are discussed in the following references: Knapp and Vanoni, 1945; 

 Hudson, 1947 and 1949; Hudson and Wilson, 1949; Palmer, Mulvihill, and 

 Funasaki, 1967; Chatham, 1968.) 



Monterey Harbor, California . 



(a) Project. Enlargement of existing harbor at Monterey, 

 California, by construction of additional breakwaters to provide safe 



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