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photographs. Even though the project has experienced a net gain in sand vol-
ume, a small amount of shoreline recession has occurred at the westerly end of
the project (Pope and Rowen 1983).
Presque Isle State Park, Erie, Pennsylvania. Presque Isle is a -I-mile-
long recurved sand spit. As part of a study leading toward a permanent
project to stabilize approximately 6 miles of the spit, three experimental
rubble-mound breakwaters were constructed in 1978 near the easterly end. T h e
breakwaters are each 125 ft long and are separated by gaps of 300 ft and
200 ft. They are located at about the -l.O-ft (LWD) contour. Approximately
5,000 cu yd of beach fill was placed in their lee. This project has also
been highly successful, although the shoreline configuration undergoes signifi-
cant changes during seasonal storms. A monitoring program, including aerial
photographs taken three times a year and ground surveys performed two times a
year, helps document the effects of different gap widths on shoreline response
(U. S. Army Engineer District, Buffalo, 1980).
Lakeshore Park, Ashtabula, Ohio. This project, completed in the fall of
1982, consists of three segmented rubble-mound breakwaters. The breakwaters
are 125 ft long and 200 ft apart and are placed in approximately 5.0 ft of
water which is about 400 ft from the original shoreline. The breakwaters are
placed in a slightly arched configuration to provide better protection to an
800-ft-long and 150-ft-wide beach fill (34,500 cu yd). Essentially, no natural
littoral material can enter the project due to the presence of Ashtabula Harbor
to the west and a large water intake structure to the east. The beach fill
is still adjusting to the incident wave climate, and aerial photography and
ground surveys are being taken to monitor the beach changes (U. S. Army Engi-
neer District, Buffalo, 1982).
S U M M A R Y : Currently, there are no simple explicit techniques for designing
highly effective and efficient offshore breakwater systems, due to the com-
plexity of the problem and to the scarcity of data and field experience. Many
of the physical processes involved are not thoroughly understood, and it will
probably be some time before a comprehensive understanding of these complex
processes is realized. Subjective judgements are required to estimate shore-
line response as a function of wave climatology, project design, and sediment
characteristics. An understanding of the nearshore sediment transport regime
and preproject sediment budget is essential. Such a qualitative design is
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