Table 1 1
Metlakatla Harbor
Annette Island, Alaska
Date
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
rubble-mound breakwater. The break-
water was constructed to elevation +22 ft mllw, crest width of ft,
and side slopes of
seaward and
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.
The harbor is illustrated in Figure 29, and an aerial photograph of
1985
the harbor is presented in Figure 30. There are no reports of needed
repairs or rehabilitation.
New Harbor
The new harbor project was adopted.
1972
18
91
Rubble-mound breakwaters were constructed, including a 1,255-ft west
breakwater and a 1,150-ft east breakwater. The breakwaters were con-
mllw, crest widths of 6.5 ft except
structed to elevation
for a 5-ft crest width on the first 660
of the east breakwater,
The west breakwater was covered with a
and side slopes of
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
- 1 1 ft mllw on the seaward side and +14
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
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
lb) 50 percent greater than 500 lb. The
armor rock
to
secondary rock weighed 20 to 300 lb, and the core rock was greater
sieve and less than 1,000 lb. The design wave was 6.1 ft,
than a
cross sections are shown in Figure 32.
(Continued)
77
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