Analysis and Ranking of the Acoustic Disturbance Potential of ...

Report No. 6945
BBN Systems and Technologies Corporation
often passing through within an hour. This results in addition of noise
contributions from several large sources and a resulting increase in the
ensonified area beyond that normally expected for a single source. Zone of
influence estimates which have been made for the North Aleutian Planning area
in Section 5.3 would also generally apply in the St. George Basin area north
and nest of Unimak Pass since the ship traffic density and TL characteristics
are expected to be comparable. Observations for specific locations in this
area are given in the following discussion.
1) Akutan Harbor, Akutan Island: A large fish processor has been
operating in this harbor. Numerous diesel and gasoline-powered fishing
vessels deliver catches to the processor, and also seek shelter and drop
anchor in the harbor. Noises from various engines, compressors and other
activities also emanate from the fish processor. Many small outboard-powered
boats from the village also regularly operate in the harbor.
The village is served by one amphibious twin-engine Gruman Goose landing
and taking off from the water near the village almost every day (i.e., every
day that weather permits). Also, other single-engine floatplanes frequently
visit and use the harbor.
2) Lost Haibor, Akun Island: A situation very similar to that described
for Akutan Harbor also exists at Lost Harbor on Akun Island in the eastern
Aleutian Islands (D. Herter, pers. comm.). A major difference between the two
harbors is the lack of a village in Lost Harbor. There is considerable local
small boat and fishing vessel traffic and some floatplane traffic operating in
the vicinity of a fish processor.
3) Unimak Pass: Unimak Pass in the eastern Aleutian Islands which is
about 19 km (12 mi) wide, accommodates high volumes of international shipping
traffic. This can include several large ocean-going vessels, including car
and log-carriers, container ships and freighters, per day). Also, large
numbers of foreign and domestic fishing vessels use the pass year-around.
Shipping traffic is heavy, often including several vessels per hour, and
generally spreads over a several mile-wide corridor when several vessels sail
through the pass simultaneously. On one typical day in August 1982, ship
traffic through Unimak Pass included four large commercial ships (one westbound
car-carrier, one west-bound log-carrier, one west-bound freighter and
one east-bound freighter, all in excess of 500 ft long), one U.S. Coast Guard
Cutter (west-bound and about 300 ft long), and two smaller fishing vessels
(both west-bound and about 100 ft long). These vessels were seen passing
within about four miles of a 200 ft long NOAA ship sailing through the pass
during a two hour interval (D.G. Roseneau, pers. obs.). On occasion, major
elements of large fishing fleets containing dozens of vessels may sail through
the pass one after another in only a few hours or days time.
5.1.8 Shumagin
The north end of the Shumagin Planning Area is traversed by the ship and
barge traffic using Unimak Pass. As a result the combined noise output from
this traffic becomes the major noise contributor in this region. Small boat
and aircraft traffic near shore are secondary noise sources. Oil exploration