Federal Register, Volume 76, Number 149, August 3, 2011, Pages 46595-47054 Page: 47,034
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47034 Federal Register/Vol. 76, No. 149/Wednesday, August 3, 2011 /Rules and Regulations
TABLE 1-CONDITIONAL OIL SPILL PROBABILITIES (PERCENT) IN REGARD TO ENVIRONMENTAL RESOURCE AREAS (ERAS)
AND LAND SEGMENTS (LSS) FOR LAUNCH AREAS (LAS) AND PIPELINES (PLS) OFFSHORE OF FOUR OIL AND GAS IN-
DUSTRY SITES. VALUES IN PARENTHESES ARE FOR PIPELINE SEGMENTS-Continued
[* = Less than one-half percent.]
Launch area Season
of spill ERA ERA ERA ERA ERA ERA ERA LS85 LS97 LS 102 LS 107 LS 138 LS 144 LS 145
(pipeline seg- (duration 55 92 93 94 95 96 100 LS 85 LS 97 LS 102 LS 107 LS 138 LS 144 LS 145
meant) of spill)
Winter 1(1) 2(3) *(*) *(*) *(*) 1(1) *(*) 3(4) 2(1) *(*) *(*) 2(2) 29(29) 1(1)
LA 12 (PL 11) Summer *(2) 12(12) 7(3) 2(1) 1(*) 13(6) 3(2) *(*) 7(6) 1(1) 1(1) 9(3) 33(29) 1(*)
Winter 1(1) 11(8) 1(*) 1(*) *(*) 12(2) 1(*) 3(3) 4(4) *(*) *(*) 3(2) 31(28) 2(1)
LA 12 (PL 12) Summer *(*) 12(9) 7(7) 2(3) 1(1) 13(12) 3(5) *(*) 7(5) 1(2) 1(3) 9(11) 33(32) 1(1)
Winter 1(1) 11(8) 1(1) 1(1) *(*) 12(11) 1(1) 3(3) 4(3) *(1) *(1) 3(4) 31(30) 2(2)
Definitions of ERAs and LSs, from Tables A.1-13, A.1-20, and A.1-22 (MMS, 2008).
ERA 55: Point Barrow, Plover Islands (Aug-Nov).
ERA 92: Thetis, Jones, Cottle and Return Islands, West Dock (Jan-Dec).
ERA 93: Cross and No Name Island (Aug-Nov).
ERA 94: Maguire Islands, Flaxman Island, Barrier Islands (Jan-Dec).
ERA 95: Arey and Barter Islands and Bernard Spit (Aug-Nov).
ERA 96: Midway, Cross and Bartlett Islands (May-October).
ERA 100: Jago and Tapkaurak Spits (May-October).
Seasonal LS 85: Barrow, Browerville, Elson Lagoon (August-November).
LS 97: Beechey Point, Bertoncini, Bodfish, Cottle and, Jones Islands, Milne Point, Simpson Lagoon.
LS 102: Flaxman Island, Maguire Islands, North Star Island, Point Hopson, Point Sweeney, Point Thomson, Staines River.
LS 107: Bernard Harbor, Jago Lagoon, Kaktovik, Kaktovik Lagoon.
Grouped LS 138: Arctic National Wildlife Refuge (Jan-Dec).
Grouped LS 144: United States Beaufort Coast (Jan-Dec).
Grouped LS 145: Canada Beaufort Coast (Jan-Dec).
Polar bears are most vulnerable to a
large oil spill during the open-water
period, when bears form aggregations on
shore. In the Beaufort Sea, these
aggregations often form in the fall near
subsistence-harvested bowhead whale
carcasses. Specific aggregation areas
include Point Barrow, Cross Island, and
Kaktovik. In recent years, more than 60
polar bears have been observed feeding
on whale carcasses just outside of
Kaktovik, and in the autumn of 2002,
NSB and Service biologists documented
more than 100 polar bears in and
around Barrow. In order for significant
impacts to polar bears to occur, (1) A
large oil spill would have to occur, (2)
oil would have to contact an area where
polar bears aggregate, and (3) the
aggregation of polar bears would have to
occur at the same time as the spill. The
risk of all three of these events occurring
simultaneously is extremely low.
We identified polar bear aggregations
in environmental resource areas and
non-grouped land segments (ERA 55,
93, 95, 96, 100; LS 85, 107). Assuming
a spill occurs during summer or winter,
the OSRA estimates the chance of
contacting these aggregations is 13
percent or less (Table 1). The OSRA
estimates LA12 has the highest chance
of a large spill contacting ERA 96
(Midway, Cross, and Bartlett islands).
Some polar bears aggregate at these
islands during August-October (3
months). If a large oil spill occurred and
contacted those aggregation sites outside
of that timeframe of use by polar bears,
potential impacts to polar bears would
Coastal areas, such as the Arctic
National Wildlife Refuge (ANWR) and
nearshore barrier islands exhibiting
relief (containing tundra habitat),
provide important denning habitat for
polar bears (Amstrup 1993, Amstrup
and Gardner 1994, Durner et al. 2006,
USFWS unpubl. data). Considering that
65 percent of confirmed terrestrial dens
found in Alaska from 1981-2005 were
on coastal or island bluffs (Durner et al.
2006), oiling of such habitats could have
negative effects on polar bears, although
the specific nature and ramifications of
such effects are unknown.
Assuming a large oil spill occurs, and
extrapolating the OSRA estimates to
tundra relief barrier islands (ERA 92, 93,
and 94, LS 97 and 102); these areas have
up to a 12 percent chance of a large spill
contacting them (with a range of less
than 0.5 percent to 12 percent) from
LA12 (Table 1). The OSRA estimates
suggest that there is an 11 percent
chance that oil would contact the
coastline of the ANWR (LS 138). The
Kaktovik area (ERA 95 and 100, LS 107)
has up to a 5 percent chance of spill
contact, assuming spills occur during
the summer season and contact the
coastline within 60 days. The chance of
a spill contacting the coast near Barrow
(ERA 55, LS 85) would be as high as 5
percent (Table 1).
All barrier islands are important
resting and travel corridors for polar
bears; larger barrier islands that contain
tundra relief are also important denning
habitat. Tundra-bearing barrier islands
within the geographic region and near
oil field development are the Jones
Island group of Pingok, Bertoncini,
Bodfish, Cottle, Howe, Foggy, Tigvariak,
and Flaxman islands. In addition, Cross
Island has gravel relief, and polar bears
have denned on it. The Jones Island
group is located in ERA 92 and LS 97.
If a spill were to originate from an LA
8 pipeline segment during the summer
months, the probability that this spill
would contact these land segments
could be as great as 8 percent. The
probability that a spill from LA10 would
contact the Jones Island group would
range from 1 percent to as high as 11
percent. Likewise, for LA 12, PL 11 and
the LA 12, PL 12, the range would be
from 4 percent to as high as 12 percent
and from 3 percent to as high as 12
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