Table 11 



Metlakabla Harbor 



Annette Island, Alaska 



Date(s) Construction and Rehabilitation History 



Old Harbor 



1945 The project was adopted. 



1956 The project was completed, including dredging 2.18 acres to -10 ft 

 mllw and constructing a 900-ft rubble-mound breakwater. The break- 

 water was constructed to elevation +22 ft mllw, crest width of 4 ft, 

 and side slopes of 1:1.5 seaward and 1:1.25 on the basin side. The 

 rock fill core was covered with a 3.5-ft layer of armor rock on the 

 crest and the seaward side, A cross section of the breakwater is 

 shown in Figure 29. 



1985 The harbor is illustrated in Figure 29, and an aerial photograph of 



the harbor is presented in Figure 30. There are no reports of needed 

 repairs or rehabilitation. 



New Harbor 



1972 The new harbor project was adopted. 



1981 Rubble-mound breakwaters were constructed, including a 1,255-ft west 

 breakwater and a 1,150-ft east breakwater. The breakwaters were con- 

 structed to elevation +23.5 ft mllw, crest widths of 6.5 ft except 

 for a 5-ft crest width on the first 66O ft of the east breakwater, 

 and side slopes of 1:1.5. The west breakwater was covered with a 

 4.5-ft-thick armor layer over a 2-ft-thick layer of secondary rock, 

 on the crest and the seaward sides, and to +12 or +14 ft mllw on the 

 basin side or to the toe on the basin side at the end. The rest of 

 the basin side was covered with a 6. 5-ft layer of secondary rock. 

 The east breakwater was covered with armor stone on the crest and to 

 -11 ft mllw on the seaward side and +14 ft mllw on the basin side, 

 and to the toe at the end. The armor layer was 4.5 ft thick, except 

 for a 3. 5-ft- thick layer over the first 660 ft, all over a 2-ft-thick 

 secondary rock layer. The secondary rock layer was 6.5 ft thick in 

 areas not covered with armor rock (or 5.5 ft thick over the first 

 660 ft where not covered with armor rock). All armor rock was Class 

 "A", 900 to 1,500 lb with 50 percent greater than 1,200 lb, except 

 the first 660 ft of the east Jetty which was covered with Class "B" 

 armor rock (300 to 900 lb) 50 percent greater than 500 lb. The 

 secondary rock weighed 20 to 300 lb, and the core rock was greater 

 than a #4 sieve and less than 1,000 lb. The design wave was 6.1 ft, 

 nonbreaking. The harbor is illustrated in Figure 31; breakwater 

 cross sections are shown in Figure 32. 



(Continued) 

 77 



