Table 22
Manistiaue Harbor Breakwaters
Manistique, Michigan
Construction and Rehabilitation History
Date
A 420-ft-long timber crib breakwater was constructed offshore of the
1887
site (Figures 59 and 60, Section E. The structure was about 29 ft
)
wide, and stone was placed on each side of the breakwater. Core
stone ranged from 2 to 3 ft in thickness, and cover stone was a mini-
mum of 4.5 ft thick.
A 322-ft-long stone-filled timber crib pier was completed west of the
1909
Section H. The pier was approx-
harbor entrance (Figures 59 and 61,
)
imately 20 ft wide and installed at
an el of
ft lwd. The lakeward
concrete cap (cast in place) and
portion of the structure included a
riprap toe protection. The rest of
the pier consisted of a cap of
precast concrete blocks and stone.
During this time, construction of the east and west breakwaters was
1911-
completed (Figure 59, Sections A- G). The 420-ft-long breakwater
1915
(built in 1887) was capped with concrete and became a portion of the
east breakwater. The shoreward 624 ft of the east breakwater and
were con-
structed of woodpiling and stone. The superstructure consisted of a
concrete cap and stone. The shoreward portion (Section A ) was 8 ft
wide, and the rest of the structure (Section B) was 11 ft wide. The
ft lwd, and stone was included on both sides. The
crest el was
1,000-ft-long lakeward end of the west breakwater and 300 ft of the
east breakwater shoreward of the dogleg section (Figures 59 and 60,
Sections C and D) consisted of wooden crib construction with concrete
caps. The 300 ft of east breakwater and 500-ft-long shoreward end of
were 20 ft wide. The
the portion of the west breakwater (Section
outer 500-ft-long portion of the west structure (Section
was built
had a
ft
24 ft wide. The breakwaters (Sections C and
crest el. The outer 400 ft of the east breakwater (Figures 59
and 61, Sections F and G) consisted of timber crib construction with
concrete caps. The breakwater was 24 ft wide and had a crest el of
ft lwd.
1953
The shoreward end of the east breakwater was extended 200 ft to
shore and 300 ft parallel to the shoreline (Figures 59 and 61, Sec-
tion I. The structure was of rubble-mound construction with
)
side slopes. It had an 8-ft crest width and
ft lwd crest el.
Cover stone on the lakeside ranged from 1 to 3 tons and on the harbor
side from 0.5 to 1.5 tons. The structure presently is entirely on
shore.
1957
The superstructure of the inner 924 ft of the east breakwater (Fig-
ure 59, Sections A , B, and C) was refilled with stone.
(Continued)
99
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