Augustine Harbor North Groin and South Jetty
Augustine Harbor, Florida, SAJ
Construction and Rehabilitation History
During 1941 a sand-tight terminal groin of timber wall, native
stone, and granite was constructed to a length of 1,580 ft, and
450 lin ft of cresote-treated timber was placed at its shoreward end
widths varied from 6 to 12 ft, and the crown elevation varied from
at the shoreward and seaward ends, respectively. A
2-ft-thick mat foundation was placed using 8,000 tons of native
stone, and 13,300 tons of mostly 5- to 10-ton stone was used to com-
plete the groin. (The largest stone was to be placed at the seaward
end.) The cost of the structure was 5,000.
Granite stone, weighing 600 tons, was placed on the south side of
the north groin at an exposed section of core wall. This placement
was necessary since sand had been accreting on the north side and
eroding on the south side to the point that the highwater line was
150 ft west of the structure. Cost of the repair was ,200.
Repairs were made to 350 ft of the existing north groin, and a
300-ft shoreward extension was completed using 20- to 100-lb core
stone and 300- to 1,000-lb cap stone to guard against flanking of
the structure by the continued recession of the shoreline south of
the groin. The repairs cost ,600.
The seaward 100 ft of north groin had gradually subsided below
A 2,825-ft-long sand-tight south jetty was constructed (Figure 28)
approximately 2,400 ft south of the existing north groin, providing
16-ft-deep channel. The sand-tight section (land-
was constructed to
ft mlw with a
side slopes. The cover stone was 2 to 8 tons with
a core of 200-lb maximum stone placed on a 2.5-ft-thick foundation
blanket (the entire length of the jetty) of 1- to 12-in. pieces.
Seaward of this section the crown width was 12 ft, the crest eleva-
ft (via 300-ft transition), and the side slopes were
The core stone was 200 to 4,000 lb, and the cover stone
consisted to 6- to 10-ton stone. The outermost 350 ft of the struc-
ture had side slopes of
and used 10-ton minimum cover stone.
The channel side of the jetty was protected by a 3-ft-thick apron,
40 ft wide consisting of a
filter bed of 1- to 12-in.
stone, overlayed with 75- to 1,500-lb riprap stone. The total cost
of the jetty plus a shoreward revetment section was 7,000.