monthly temperatures range from about 60C in
increment of emissions to cause a significant im-
July and August to about 28C in December and
pact. Development of a compacted-snow runway
January. The mean annual temperature is 49.3C
at the South Pole Station would be a net beneficial
(Schwerdtfeger 1984). Precipitation at the South
impact during any rebuilding project because
Pole is either light snow or, more frequently, ice
wheeled aircraft could be used, at least in part, to
crystals. The estimated annual average accumu-
support science at the South Pole and provide,
lation is 7 cm of water equivalent (Schwerdtfeger
therefore, more efficient operation, fewer flights
1984).
to deliver the same amount of cargo, and less fuel
Snow is lost only by ablation or blowing to-
used. Long-term development of a runway for
ward the edge of the continent. Snow has accu-
wheeled aircraft may not be economically fea-
mulated and formed an ice cap over the continent
sible after any rebuilding project has been com-
about 2,850 m thick. This ice sheet moves about
pleted.
10 m/year toward the Weddell Sea (Giovinetto
and Bentley 1985). The South Pole site includes
Environmental consequences of
the current station completed in 1975 and former
the no-action alternative
facilities now covered by snow. Because the South
Under the no-action alternative, any reconstruc-
Pole Station is located on the high-altitude, in-
tion of the South Pole Station would be depen-
land plateau, there are no aquatic or terrestrial
dent on using LC-130s to transport construction
ecological resources.
materials and equipment or other alternatives such
as overland traverse or airdrops. Environmental
Environmental consequences of
impacts of using LC-130s would be similar to
developing a compacted-snow runway
those from existing operations (NSF 1991). Be-
Construction of a compacted-snow runway is
cause of the limited cargo capability of the LC-
expected to have only "minor or transitory" (that
130s, any construction period would have to be
is, no significant) environmental impacts. Addi-
extended. Use of LC-130s to transport construc-
tional personnel and specialized equipment would
tion materials, equipment, and personnel would
be required to prepare the runway because main-
greatly limit the available support for science and
tenance of the existing skiway would continue to
would have a significant adverse impact on the
be needed. Operation of a compacted-snow run-
science program. Use of airdrops would increase
way would result in similar impacts to those ex-
the cost of transport. Overland traverse of materi-
perienced with the existing skiway. Spills and
als from McMurdo is possible, but very expen-
leaks of oil, fuel, lubricants, and other fluids from
sive, and it would involve an extended risk to the
aircraft, runway construction and maintenance
safety and health of personnel involved with the
equipment, and fuel storage sites could result in
traverse.
deterioration of the compacted-snow surface and
would be cleaned up to the extent possible. To
Other potential
avoid or minimize impacts from contaminated
blue-ice runway sites
snow materials, NSF would instruct its contractor
to collect and process contaminated snow materi-
Affected environment
als to remove contaminants. Contaminated mate-
Very little is known about most of the 84 po-
rials would then be transported to McMurdo for
tential airfield sites identified by Swithinbank
appropriate retrograde from Antarctica.
(1991). In most cases, no one has ever visited the
Assuming that the present level of scientific
sites identified from the aerial photographs. One
research would be maintained during any con-
important exception is the Patriot Hills blue-ice
struction activities at the South Pole Station, a
site that is located to the north of the isolated
greater number of flights would occur involving
Patriot Hills ridge in the Ellsworth Mountains
(Fig. B3). The ice field covers a 2-km 8-km area
a combination of ski-equipped LC-130 and
wheeled C-130 aircraft. As a result of more flights,
and is low in elevation (750 m) relative to Mount
there would be a higher level of atmospheric emis-
Howe and Mill Glacier. The site has been used for
sions from aircraft during this period. Impacts
wheel landings of DC-4 aircraft, and temporary
from aircraft emissions have been discussed in
camps capable of housing up to 40 people have
the SEIS (NSF 1991), and the increased level of
been maintained during the summer months on
flights that would result from any construction
the moraine at Patriot Hills (Mellor and Swithin-
activities at South Pole would not add a sufficient
bank 1989). Currently, the site is used for wheel
109
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