OFFSHORE BREAKWATER PROJECTS ON LAKE ERIE:
The scarcity of adequate recrea-
problems has
tional beaches on the Great Lakes
combined with severe erosion
created a great deal of interest in the use of offshore breakwaters as beach
stabilization
and
devices.
They are appealing since they can be
designed as a single unit or as a series of units (segmented) and are
adaptable
to many coastal environments.
As of 1983, the Buffalo District had constructed
(1) three permanent segmented offshore breakwater projects and (2) a temporary
project in which three different types of low-cost single offshore breakwaters
were constructed and monitored at Geneva State Park, Geneva, Ohio.
The
perma-
nent projects are located at
Lakeview
Park, Lorain,
Ohio; Lakeshore Park,
Ashtabula,
Ohio; and at Presque Isle State Park,
Erie,
Pennsylvania
(Figure
1);
each includes three segmented rubble-mound breakwaters that were constructed
for beach restoration and erosion control.
The four projects are described
below.
Geneva State Park, Geneva, Ohio.
As part of a nationwide program to
construct and monitor various types of low-cost shore protection devices,
three different types of offshore breakwaters, each 100 ft long, were in-
stalled at Geneva State Park.
They included a
gabion
breakwater (rock-filled
wire
baskets), a sta-pod breakwater (26 freestanding precast concrete units,
each wei.hing 2 tons, placed in a single row), and a Z-Wall (14 precast con-
g .
crete wall panels, weighing 6.5 tons each, connected in a zigzag pattern).
The breakwaters were constructed in 1978 and were placed approximately 75 ft
offshore and 500 ft apart to ensure their independent functioning.
The
struc-
tures performed with different degrees of success, and much information was
gained on structural stability, porosity effects, and foundation design
(OCE 1981).
Lakeview
Park, Lorain, Ohio.
In 1977, a series of three segmented off-
shore breakwaters were constructed at
Lakeview
Park to protect a sand
beach-
fill that was placed to create a 1250-ft-long
recreational beach. The park
was initially void of any
useable
beach and was suffering severe erosion when
The design called for three 250-ft-long
rubble-
the project was implemented.
mound breakwaters spaced 160 ft apart and placed 400 to 500 ft from the orig-
The beach
100,000 cu yd of beach fill material was placed.
inal
shoreline.
is terminated by a short 130-ft concrete
groin on the
updrift
(west) side and
The project has been very
a 300-ft rubble-mound groin on the downdrift side.
successful and has been monitored closely through ground surveys and aerial
4
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