Table 73 



Port Sanilac Harbor Breakwaters 



Port Sanilac, Michigan 



Date(s) Construction and Rehabilitation History 



1951 Construction of a 1 ,230-ft-long north breakwater and a 949-ft-long 

 south breakwater (Figure 195, Types A, B, C, and D) was completed. 

 The shoreward ends of both structures consisted of steel sheetpiling 

 with an el of +8.0 ft Iwd (Figure 196, Type D) . Riprap was placed on 

 the lakesides of the structures. The remaining portions of the 

 breakwaters were constructed of sand- and gravel-filled cellular 

 steel sheet-pile structures with cell diameters ranging from 23.87 

 (Figure 196, Type A) to 28.85 ft (Figure 196, Types B and C) . The 

 Type C structure at the lakeward end of the north breakwater (Fig- 

 ure 196) had a crest el of +10 ft Iwd, and the remaining portions 

 (Types A and B) were installed at a +8 ft Iwd crest el. Riprap was 

 placed on both sides of the lakeward portion of the north breakwater 

 (Type C) and on only the lakesides of the cells of the remaining 

 structures (Types A and B) . The cells were capped with asphalt. 



1975 To reduce wave heights in the harbor to approximately one-half foot, 

 a 327-ft-long extension to the north breakwater and a 69-ft-long ex- 

 tension of the south breakwater (Figure 195, Types E and F) was com- 

 pleted. The north breakwater extension consisted of stone-filled, 

 steel sheet-pile cells with a diameter of 43 ft and a crest el of 

 +10 ft Iwd (Figure 196, Type E) . The south breakwater extension was 

 constructed of stone-filled cellular sheet piles (Figure 196, Type F) 

 with diameters of 31.8 ft and a crest el of +8 ft Iwd. The exten- 

 sions were capped with bituminous concrete. Riprap stone ranging 

 from 1,000 lb to 1 ton was placed on both sides of the north break- 

 water extension and on the lakeside of the south extension. 



1984 A site inspection of the structures revealed that some of the asphalt 

 caps of the north breakwater had settled, but the breakwaters were 

 generally in good condition. An aerial view of the Port Sanilac 

 Harbor breakwaters is shown in Figure 197. 



298 



