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

Report No. 6945
BBN Systems and Technologies Corporation
In Section 2 the distribution of marine mammal species was described on a
species-by-species basis. However, since the distributions of various sound
sources in the Alaskan marine environment are very diverse and variable, it is
more useful to discuss the source distribution on a planning area basis. A
detailed description of the sources and their locations has been developed and
is presented in the form of a summary table together with a narrative discussion
focussed primarily. on the Alaskan coastal OCS planning areas, including
adjacent landward regions, with emphasis on the Chukchi Sea, Norton Basin,
North Aleutian Basin, and Shumagin Areas.
Source distribution information for the most significant source types has
also been used to produce two map overlays which can be used with the species
distribution maps presented in Section 2. These overlays show estimated
source distribution patterns for fishing vessel, commercial shipping, aircraft,
and cultural activities. The overlays, which are self-explanatory, are
located in an envelope inside the back cover of this report.
5.1.1 Beaufort Sea
This area has been the location of much oil exploration and offshore
drilling activity in recent years and several specific studies of underwater
noise have been completed in the region (Miles et al. 1987, Greene 1987a,
Ljungblad et al. 1985). The seismic sources, icebreakers, drillships, supply
vessels 2nd helicopter traffic associated with this activity are the major
sources of man-made noise in this area. Secondary sources are supply barge
activity for the Prudhoe Bay complex, commercial air traffic into Prudhoe Bay
and Barrow, and hunting from small motor-powered vessels. A listing of the
major sources is given in Table 5.1.
5.1.2 Chukchi Sea
Little direct information is available on man-made noise in the Chukchi
Sea. The seismic source activity required for oil and gas development is
undoubtedly a dominant noise contributor for this region. The noise produced
by icebreakers that occasionally pass through this region will be louder than
that produced by locally operating sources. Supply barge and aircraft traffic
are secondary contributors. Some observations for specific areas are as
follows :
1) Point Lay: Some small boat traffic occurs along the coast in the
vicinity of the summering whales when residents of Point Lay and Wainwright
visit one another, or travel to coastal hunting and fishing camps, or go on
other hunting forays. Also, some low-level aircraft traffic occurs along the
coast between Point Lay, Wainwright and Barrow nearly every day. Single and
twin-engine airtaxi aircraft often follow the beach below 150 m (500 ft)
because of local weather conditions. An average of about one to two small
aircraft land and take off low over the coast at Point Lay per day, and about
one larger multi-engine cargo aircraft services the nearby DEW Line radar
facility each month (D. Schmidt, pers. comm.).