Document ID: EPA-HQ-OW-2013-0262-0005
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2014-04-22T04:00Z

PRIVATE  

	INITIAL ENVIRONMENTAL EVALUATION FOR THE PROPOSED REPLACEMENT,

	OPERATION, AND DECOMMISSIONING OF ICE WHARVES AT

	MCMURDO STATION, ANTARCTICA

	May 1992

	National Science Foundation

	Division of Polar Programs

	Washington, D.C.

		CONTENTS

1.	INTRODUCTION		1

2.	PURPOSE AND NEED FOR ACTION 	1

3.	ALTERNATIVES, INCLUDING THE PROPOSED ACTION 	3

3.1	DESCRIPTION OF THE PROPOSED ACTION 	3

		3.1.1  History of the Use of Ice Wharves at McMurdo Station 		3

		3.1.2  Construction 		6

		3.1.3  Use and Maintenance of the Ice Wharf 	11

		3.1.4  Disposal 		12

	3.2	ALTERNATIVES TO THE PROPOSED ACTION 	13

		3.2.1  Use of a Steel Barge or Barges 	13

		3.2.2  Construction of a Permanent Pier 	14

		3.2.3  Ice Dock Alternative	14

		3.2.4  No-Action Alternative 	14

4.	AFFECTED ENVIRONMENT 	15

5.	ENVIRONMENTAL CONSEQUENCES AND MITIGATION 	16

	5.1	PROPOSED ACTION 	16

	5.2	ALTERNATIVES TO THE PROPOSED ACTION 	17

		5.2.1  Use of a Steel Barge or Barges 	17

6.	FINDINGS 	19

7.	LITERATURE CITED 	21

8.	LIST OF PREPARERS	23

	ACRONYMS AND ABBREVIATIONS

ASA		Antarctic Support Associates, Inc.

cfm		cubic feet per meter

cm		centimeter or centimeters

ft		foot or feet

GPM		gallons per minute

IEE		Initial Environmental Evaluation

in.		inch or inches

kg		kilogram

L		liter or liters

lbs		pounds

m		meter or meters

min		minute

NSF		National Science Foundation

NSFA		Naval Support Force Antarctica

PCBS		Polychlorinated biphenyls

SEISSupplemental Environmental Impact Statement

USAP		U.S. Antarctic Program

INITIAL ENVIRONMENTAL EVALUATION FOR THE PROPOSED REPLACEMENT,

	OPERATION, AND DECOMMISSIONING OF ICE WHARVES AT

	MCMURDO STATION, ANTARCTICA

	1.  INTRODUCTION

	The National Science Foundation (NSF) is responsible for the U.S.
Antarctic Program (USAP) that supports a substantial scientific research
program in Antarctica, often in cooperation with other countries.  The
USAP maintains three year-round stations in Antarctica—McMurdo Station
on Ross Island (Fig. 1), the Amundsen-Scott South Pole Station, and
Palmer Station on the Antarctic Peninsula.  McMurdo Station is the major
base for providing logistics support to numerous scientific field camps
on the continent each austral summer.  Logistic and operational support
are provided by the Department of Defense [the Naval Support Force
Antarctica (NSFA), U.S. Army, and U.S. Air Force], the U.S. Department
of Transportation [U.S. Coast Guard], and a civilian contractor
[currently Antarctic Support Associates, Inc. (ASA)].

	An important component of USAP logistic support for the continent, and
for maintenance of safe conditions for personnel is the annual resupply
by ship of supplies and fuel that arrive at McMurdo in late January and
February.  Since 1976, cargo and fuel have been offloaded using an ice
wharf located in Winter Quarters Bay.  In 1991, NSF published a
Supplemental Environmental Impact Statement (SEIS) on the U.S. Antarctic
Program (NSF 1991) that contains a brief description of the ice wharf
and its use at McMurdo Station.  This Initial Environmental Evaluation
(IEE) is tiered to the SEIS and has been prepared to address
specifically the potential environmental impacts of the construction,
use, and periodic replacement of the ice wharf.

	2.  PURPOSE OF AND NEED FOR ACTION

	Docking, loading, and offloading ships at McMurdo Station, Antarctica,
require a large stable platform capable of supporting heavy equipment
and cargo and providing a safe working environment.  Since 1973, ice
wharfs have been constructed to serve this function.  An ice wharf has a
finite life and must be replaced periodically (Voelker et al., 1991, NSF
1991).  In February 1991 the ice wharf at Winter Quarters Bay developed
several cracks extending below the water 



  ADVANCE \Y 676.80 	Figure 1.  McMurdo Sound and vicinity.

line that rendered the wharf inoperable for the 1992–1993 season. 
Replacement of a new ice wharf is therefore needed to accommodate ships
that visit McMurdo Station during one period each year to offload cargo
and fuel and load wastes and other materials that are to be returned to
the United States or New Zealand for disposal or reuse.  The resupply
ship and the fuel ship are accommodated normally between the end of
January and the first two weeks of February each year.  Ice wharves may
continue to be replaced in the future.  In order to resupply McMurdo
Station during the 1992–93 season, construction of a new ice wharf, or
planning for another alternative, must be initiated during the austral
winter.

	The purpose of this IEE is to evaluate potential environmental impacts
that would result from the construction, operation, and eventual
disposal of ice wharves.  The specific actions are (1) construction of
an ice wharf during the winter season, (2) use of the ice wharf, and (3)
eventual disposal of the ice wharf when its useful life is over.

	3.  ALTERNATIVES, INCLUDING THE PROPOSED ACTION

	The proposed action is to periodically construct a new ice wharf using
methods that have been developed since the early 1970s.  In addition to
construction of new wharves, this IEE also evaluates the use of ice
wharves for offloading cargo and fuel and for other ship visits that
occur in late January and February of each season and their eventual
disposal at the end of their useful lives.

	Alternatives to the proposed action that are evaluated in this IEE are
(1) to replace the ice wharf with one or more steel barges, (2) replace
the ice wharf with an ice dock, (3) construct a permanent pier, and (4)
the no-action alternative of not replacing the ice wharf, and offloading
cargo and fuel from an anchored vessel directly onto the sea ice at some
distance from the Station.

3.1   DESCRIPTION OF THE PROPOSED ACTION

3.1.1  History of the Use of Ice Wharves at McMurdo Station

	The ice wharf has been located in Winter Quarters Bay along the Hut
Point peninsula (Fig. 2).  The ice wharf is used to dock vessels for
unloading cargo and petroleum products and

 ADVANCE \Y 676.80 	Figure 2.  McMurdo Station facilities.

for loading wastes and other materials to be retrograded to the
continental United State (or other nations when permitted).  Different
designs of this wharf have been tried over the years.  A history of the
development of docking facilities is summarized here and in Table 1.

 PRIVATE  Table 1.  History of docking facilities at McMurdo Station,
Antarctica

Year

	Pre 1964	Cargo was unloaded from ships on the annual sea ice about 10
km from McMurdo Station and moved to shore by sled.

1964	Shorefast ice at Hut Point served as a wharf.

1972	A steel and wood dock was constructed but destroyed by storm.

1972	A 7.6 ( 15.2 m non-floating ice dock was built for the 1973 season.

1973	A large floating ice wharf (140.2 m seaward face and 193.5 m
landward face) was built.  It was 6.1 to 8.8 m thick and extended 51.8 m
from shore.

1976	A second ice wharf (about 250 m on the seaward face and about 365 m
on the landward face) was completed.  It was 6.4–7.6 m thick and
extended about 90 m from shore.

1980	A third ice wharf was completed.  It's dimensions are not
documented, but it was 4.6 m thick.

1983	A fourth ice wharf was built similar in dimensions to the 1976
wharf.  Thickness of the wharf at the beginning of the summer season was
4.6 m.  Ice was added to the wharf in 1984, 1987, 1988, and 1989.  Ice
thickness probably exceeded 9 m by 1989.

1990	A fifth ice wharf was built similar in design to the 1976 wharf but
only 3.0 to 3.7 m thick.  About 1.5 m of ice was added in 1991.

1992	A new ice wharf is proposed that would have a seaward face of about
198 m and shoreward face of 256 m.  It would extend about 99 m from
shore and be 6.1–6.7 m thick.

	During the International Geophysical Year and for several years
thereafter cargo was offloaded onto the annual sea ice about 10 km from
McMurdo and hauled by sled train to Ross Island.  In 1963–64, Winters
Quarters Bay was opened by ice breaker and the shore ice was used as a
natural wharf, eliminating many hazards associated with transporting
cargo across the sea ice.  This natural wharf deteriorated and was
replaced by a steel and wood dock structure between 1968 and 1972.  This
dock was destroyed in March 1972 by small icebergs driven into Winter
Quarters Bay during a storm.  The first ice dock, 7.6 ( 15.2 m, was
built in the winter of 1972 and was used in conjunction with two short
piers for the January–February 1973 shipping season.  In 1973 a large
floating ice wharf was built that lasted through the 1975 season.  A
second large ice wharf, built in 1976, lasted until 1979 and was
replaced during the winter of 1980 (NSFA 1981).  The third wharf was
built in 1983, was repaired annually, and lasted until 1990.  In
February 1990, this pier was towed 25 km to sea for disposal (NSFA
1990).  The last ice wharf built in 1990 (Fig. 3) broke into three large
pieces in February 1992, was cabled together, and, then was resurfaced
for the 1991–1992 season.  It was removed from Winter Quarters Bay in
March 1992.

3.1.2  Construction

	Table 2 indicates the type and quantities of materials used during this
construction process.  Table 3 lists the construction equipment to be
used.  Lessons learned from the construction and operations of previous
wharves indicate that the procedures detailed in the Engineering Manual
for McMurdo Station (Hoffman 1979) should be followed in constructing a
new ice wharf.  The basic guidelines are as follows:

(1)Design the wharf to be a fully floating structure to reduce stress
due to partial grounding.

(2)Restrain the wharf from drifting out of position by use of bollards
and cable lash-up.

(3)Oversize the wharf to allow for retreat of the seaward ice face due
to the loss of ice in the annual trimming and straightening of the ship
docking face.

(4)Reinforce the wharf with steel cables so if it does crack it will
hold together until it refreezes.  Set the cables back from the face by
about 30.5 m so they do not interfere with trimming.

(5)Begin construction soon after 61 cm of sea ice has formed so the ice
is thick enough to support equipment and there is enough time to achieve
the required thickness of the wharf (6.7–7.9 m) before it is used in
January.



 ADVANCE \Y 662.40 		Figure 3.  Schematic (not to scale) of 1990 ice
wharf in Winter Quarters Bay, McMurdo Station, Antarctica.



 PRIVATE  Table 2.  Types and quantities of materials used during
construction of the ice wharf.

Type	Use	Amount (estimate)

Seawater	To make ice	170,340,000 liters

1" steel cable	Reinforce wharf	6400 m (2134 m/layer)

2" steel pipe	To enable steel cable to be looped	107 m

1.5–2.0" steel pipe	Flooding gauges	91 m

1.9 cm or smaller gravel and fines	Provide a non-slip working surface on
wharf	4,500–5,000 yd3 (3760–4180 m3)

JP-8 gas	Fuel for the construction equipment, lighting pumps, and heated
building	18,900 liters

Mogas	Gasoline for automotive and similar engines	9,500 liters

(6)Emphasize extra safety precautions when building the wharf such as
incorporating a "buddy" system for all workers because of the slippery
surfaces and difficult working conditions.

	The following procedures may be modified slightly since each
reconstruction must be specifically adopted to the existing conditions.

	Construction would begin after the sea ice reaches 61 cm in thickness. 
Snow would be bermed to a depth of about 30 to 60 cm along the perimeter
of the wharf (Fig. 4) in order to contain water that is pumped onto the
ice.  Two 5680 L/min (1500 GPM) pumps would be used to flood the wharf
surface with about 10 cm of water.  Steel pipe, 3.8 to 5.1 cm (1.5 to 2
in.) in diameter would be used as flooding gauges.  The 10.2 cm of water
is expected to freeze in about 24 hours which would allow another 10.2
cm layer to be added.  When the ice thickness of the wharf reaches 1.5 m
(Fig. 5), steel cable would be woven around a series of 5.1 cm (2 in.)
steel pipes that are set into drilled holes.  An area of about 61 ( 15.2
m would be reinforced and would require about 2130 m of cable. 
Flooding would continue to build the ice up for another 1.5 m and a
second layer of cable would be added.  A third layer would be added when
the ice is 4.6 m thick.  The finished thickness of the wharf is planned
to be 6.1 to 6.7 m.  Lighting for the

Figure 4

Figure 5



 PRIVATE  Table 3.  Equipment to be used in construction of the ice
wharf.

Type	Function

2 1500 GPM pumps	Pump water to flood the wharf for ice formation.

2 graders and a D4 and D6 dozer	Make snow berm and spread surfacing
materials.

2 forklifts	Make poles and pipe.

Grid roller	Compaction of surface materials and eliminate air bubbles in
freezing ice.

Trencher	Help create a straight smooth surface on the seaward facing
ice.

Tracked drill (auger)	Drill holes for bollard setting.

Tracked drill	Drill holes for gauges and cable loop pipe.

Compressor 600 cfm	Provide compressed air for air driven equipment.

construction period would be fixed on 9.1 m wooden utility poles. 
Shorter sections of these poles would be used for bollards.  These would
be placed into the ice by drilling and blasting holes, placing the poles
and freezing them in place with a mixture of fresh water and mineral
fines.

	Before the wharf is used for offloading a ship, a 15 to 20 cm layer of
2 cm and smaller gravel (friable pumice) taken from a borrow area would
be applied to the surface.  The seaward face of the ice wharf would also
be trimmed and straightened by trenching and/or blasting the ice.  About
20 people would be involved in the construction which would probably
begin in May and finish in October.  

3.1.3  Use and Maintenance of the Ice Wharf

	The wharf is used primarily for docking a tanker that unloads fuel in
late January and a cargo ship that unloads supplies and loads materials
for retrograde and transport back to the United States or New Zealand. 
The ice breaker that arrives in early January and research vessels that
may visit McMurdo also use the ice wharf.

	At the end of the austral summer season, the surface material would be
removed and stored for reuse the following season.  At least on one
occasion, a storm wet the surface material and froze it in place.  Ice
was than added on top of that material and new surface material was
added. Use of the wharf may result in spills of fuel, antifreeze, oil,
or hydraulic fluids.  The surface material generally absorbs such
spills.  Any noticeable spills would be cleaned up and drummed for
retrograde.  Before removal the NSFA would collect twenty (20) 10.0-gram
samples of the surfacing materials from random locations on the wharf. 
The samples would be stored frozen in pre-cleaned, 8-ounce, clean
wide-mouth glass bottles for analysis of possible contamination.  An
action plan for the sampling of earth-fill materials will be provided by
NSF to NSFA.

	Annually the seaward face of the ice pier becomes eroded by wave action
and discharge of water from ships that dock at the wharf.  In the past,
discharge of coolant water from docked ships has greatly eroded the
wharf face.  A wharf face curtain and a metal deflector shield would be
incorporated into the design to minimize erosion of the ice.  These
precautions would be taken to extend the useful life of the ice wharf.

	The eroded face of the wharf would be trimmed by explosives and
trenching.  Holes 10.2-cm wide would be drilled in a single line, to a
depth of 3.7 m on 0.9 to 1.2 m centers.  Each hole would be loaded with
a uniform charge of 3.7 m of 4,064 gr/cm (1600 gr/in.) detonation cord
(7,010 m/sec velocity). The line would be about 5 m back from the
seaward face.  After blasting, the ice breaker would clear the fractured
ice face and remove it from the bay.  The 30.5 m of ice in front of the
reinforced area of the ice wharf (Fig. 3) would provide the surface for
trimming over the life of the wharf (approximately 4 years or more).

	The wharf could be subjected to much stress due to wave action,
grounding, and ice breakout by the icebreaker.  The cable in the 61 m by
152 m area (Fig. 4) would be designed to prevent the wharf from coming
apart if cracks develop.  Part of the maintenance schedule would be to
allow the cracks to refreeze (heal) and then to form additional ice on
top to strengthen the wharf.  It is assumed that ice would be added each
year.  

3.1.4  Disposal

	When the ice wharf deteriorates (e.g., becomes too small or fractured),
it would be towed to sea and released to melt with the annual sea ice.
Prior to disposal all surfacing material has been, and would continue to
be scraped off; and all structures that can be detached would be
removed. Removal of the ice wharf is essential because it would prevent
another wharf from being built due to space limitations and would be an
obstacle to ships entering the bay.

3.2  ALTERNATIVES TO THE PROPOSED ACTION

3.2.1  Use of a Steel Barge or Barges

	An alternative to reconstructing the ice wharf is to replace it with a
relatively permanent structure that would be towed to McMurdo and
located at the site of the previous ice wharfs in Winter Quarters Bay. 
This structure would consist of one or more steel barges that could be
fabricated for or purchased by the USAP and towed to Antarctica.  The
following discussion of the steel barge alternative is based primarily
on a draft study commissioned by NSF to develop a conceptual design and
cost estimate for a steel barge to replace the ice wharf at McMurdo
Station (Voelker et al. 1991).

	Under this alternative, USAP would either contract to have a new
seagoing barge or barges constructed at a foreign or U.S. shipyard or
would purchase a conventional seagoing barge or barges currently
available on the world market due to the slumping worldwide economy. 
The conceptual design is for a single steel barge that would be 122 m
long and 30.5 m wide.  The barge would have a draft of 4.6–6.1 m and a
freeboard of 3 m, for a maximum depth of approximately 7.6 m.  The barge
would be designed for a useful life of 30 years with low maintenance. 
The design waterline, while at Winter Quarters Bay, was selected as 4.6
m; this would result in a 3-m freeboard that would provide easy access
between the barge and shore.  From the deck edge, the vertical sides
would extend 2.1 m down to permit easy use of fenders between the barge,
vessels moored alongside, and the shore.  At 0.9 m above the waterline
the vertical hull would change to a sloped lower hull to ensure that ice
features do not impinge on the vertical plates.  A specially
strengthened metal "ice belt" of 13.9 kg-plating (30.6 lb) would extend
a vertical distance of 3 m between the 5.5-m and 2.4-m waterlines.  The
standard plating used would be 9.3 kg (20.4 lbs), except for the ice
belt.  The barge would have a low friction hull coating (Inertia 160 or
equivalent).  The deck would be diamond patterned steel and would be
covered with about 10 cm of fill material from a McMurdo borrow area.
For winter freeze-in, the barge would be ballasted with diesel fuel or
some type of antifreeze and anti-corrosion fluid.  Once acquired, the
barge could be towed to Antarctica by the U.S. Coast Guard icebreaker
that makes an annual round trip to Antarctica or by a specially
chartered seagoing tug.  The barge would be moored to the shore at
Winter Quarters Bay.

	The conceptual design for building a single barge as described above
would provide a smaller work area (122 ( 30.5 m) than the 152 ( 61 m
area initially envisioned.  The single barge design was based on
standard engineering design criteria for length, breadth, and depth for
an ocean-going barge.  The Voelker et al. (1991) study suggests that a
larger work area might be achieved by using two or four barges.  Should
this option be pursued, uncertainties about ice build up between the
barges and possible twisting moments from cargo stored on one of the
barges or being transferred from one barge to another would need to be
evaluated.  The single-barge wharf could be equipped with a conveyer
system for moving the cargo from ship to shore rather than using
tractors and trailers, thus compensating for the reduced work area.

	This option using steel barges could be a possible long-term solution. 
It would take 2–4 years to implement, but would require low
maintenance over a 30- to 35-year expected lifetime.

3.2.2  Construction of a Permanent Pier

	After the natural shorefront ice was destroyed through use and wave
action in 1968, an attempt was made to replace it with a steel and wood
panel structure.  This structure was completed in 1972 but was promptly
destroyed by a storm that drove ice against the dock.  It took several
years to remove the debris and some steel I beams may still be frozen in
the ice near the shore.  The failure of this dock emphasizes the need
for the wharf structure to be able to withstand heavy pounding of surf
and small icebergs.  Currently no permanent pier structure has been
designed for McMurdo Station, and history and recurring extreme sea
state conditions suggests this alternative is not feasible and is not
considered further.

3.2.3  Ice Dock Alternative

	Building an ice dock at Winter Quarters Bay differs from constructing
an ice wharf in three major ways.  First, an ice dock is much smaller
than an ice wharf.  The previous ice dock was 7.6 ( 15.2 m and was a
simple platform onto which containers were lifted for removal.  Because
it is not large enough for large trucks to turn around on, the handling
time and unloading time is greatly increased.  Second, the work would
have to take place near the edge of the dock, thus creating a safety
hazard.  Third, the dock cannot be used for mooring a ship, and thus all
lines would need to be tied to shore as well as sea anchors deployed. 
Safety of the vessel would be a concern in the event of a severe storm. 
This alternative is, therefore, not considered viable and is not
considered further.

3.2.4  The No-Action Alternative

	This alternative would require ships to dock at the sea ice edge some
distance from McMurdo.  The sea-ice alternative would require all cargo
containers to be small enough to be moved by sled and light enough to be
supported by the sea ice.  The time to offload and load the ship which
currently takes 12–14 days using the ice wharf would be greatly
extended.  Over 9 million metric tons of material comes into and out of
McMurdo each year by ship.  Also, this is the time when the ice is
becoming thin and safety on that ice is an overriding USAP concern.  The
extended time needed to offload the ships, the constraints on container
size, and safety concerns indicate that this alternative is not viable,
and no further discussion of it is provided here.

	4.  AFFECTED ENVIRONMENT

	McMurdo Station (77(51(S, 166(40(E) is the major support station for
the USAP.  The station is located on Ross Island and consists of more
than 100 structures, extensive storage yards, an ice wharf, an annual
sea-ice runway, a skiway, a helicopter landing area, and other ancillary
structures and features (e.g., communications antennas and roads).

	McMurdo Station is located on a southward-projecting peninsula of Ross
Island at the edge of the Ross Ice Shelf (Fig. 1).  Its weather is
affected by cold air drainage flowing off the continent and ice shelf
and strong cyclones that develop over the Ross and Amundsen seas.  Mean
monthly temperatures at McMurdo range from -3(C (26( F) in December and
January to -28(C (-18(F) in August.  Extreme maximum and minimum
temperatures of 7(C (42(F) and -51(C (-59(F), respectively, were
recorded during a 13-year period at McMurdo.  The mean annual
temperature is approximately -18(C (0(F).  The average precipitation is
17.4 cm of water equivalent annually.  Ice fog is common throughout the
year and sometimes reduces visibility to zero.

	Man's activities at McMurdo have greatly influenced the benthic
populations of Winter Quarters Bay.  Inorganic material such as
discarded equipment and general trash litter the bottom of Winter
Quarters Bay and can be found up to 6 km north to the Cinder Cones
(Dayton and Robilliard 1971).  Levels of purgeable hydrocarbons in
Winter Quarters Bay sediments are as high as 4500 ppm (Lenihan et al.
1990) and are pyrolytic in origin (i.e., products of incomplete burning
or generated by such high temperatures as those encountered in engines).
 Polychlorinated biphenyls (PCBs) with a composition identical to that
of Arochlor 1260 are present in the sediment on the order of 1 ppm, a
level that would be considered high in coastal or estuarine
environments.  This pollution is primarily confined to the bay
(approximately 0.1 km2 in area) because of limited circulation and an
underwater sill that partially encloses the bay and restricts water
movement and flushing (Risebrough et al. 1990).  Fill material along the
shore of the wharf area has eroded into the bay for about 8 to 9 m
(Voelker et al. 1991, Appendix B).

	McMurdo Sound is a deep body of water with depths reaching 500 m just
10 km west of McMurdo (Barry and Dayton 1988).  Ross Island and adjacent
McMurdo Sound provide important breeding sites for such marine mammals
and bird species as Weddell seals, Adelie penguins, and Emperor
penguins.  Weddell seals and migratory skuas are the most conspicuous
wildlife in the immediate vicinity of McMurdo Station.  Killer whales
and leopard seals are present in the area and prey on seals and penguins
in the vicinity when open channels form in the ice.

	Because more than 97% of Antarctica's 14-million-km2 land mass is
covered by ice, exposed rock and other substrate available to support
terrestrial ecosystems is limited.

	5.  ENVIRONMENTAL CONSEQUENCES AND MITIGATION

5.1  PROPOSED ACTION

	Environmental impacts from the construction, operation, and disposal of
the ice wharf are minimal.  These consist of fuel use and associated
emissions, construction material use, disposal at sea, collection and
use of surfacing material, use of explosives, and safety issues.  The
use of about 18,900 liters of JP8 and 9,500 liters of Mogas (gasoline)
to run the construction equipment and provide for the electricity for
the pumps is less than 0.01 percent of the fuel burned at McMurdo each
year.  The total emissions from use of fuel at McMurdo have been
evaluated in the SEIS for the U.S. Antarctica Program and found to have
been both less than minor or transitory impacts (NSF 1991). 
Construction material consists primarily of steel and water.  There are
also some wooden utility poles that would be imbedded in the wharf. 
Transportation of these materials to McMurdo would result in no impacts
of concern, because they represent a very small percentage of the cargo
on the resupply ship (cargo may exceed 6.5 million metric tons). 
Disposal of these items at sea as the wharf melts should result in
little adverse impact.  The steel would eventually dissolve through
oxidation unless it is released to deep waters that are anaerobic.  Iron
released through oxidation provides a limiting nutrient for
phytoplankton production.  The utility poles would be likely to float
for several years, providing substrate for attachment of sessile
organism until they are destroyed by biological processes.  Collection
and use of the fill materials is an ongoing action at McMurdo Station,
occurs only at designated borrow areas, and results in acceptable
impacts (NSF 1991).  Efforts to collect all contaminated fill on the ice
wharves for retrograde should prevent impacts due to the spread of any
hazardous substances.  

	Safety in Antarctica is a primary concern and is given highest priority
by USAP.  The ice wharf would be used only by people with ice safety
training and by qualified equipment operators.  If existing guidelines
are followed, the wharf greatly increases the safety of offloading and
loading compared to the no-action alternative of using the sea ice or an
ice dock that is too small for safe equipment operation.  Use of
explosives to trim the ice face usually results in only a few
detonations of a line of charges per year.  These operations would be
performed only by qualified personal with the proper training.  No
safety problems from these operations have been noted in the past or are
expected in the future.

5.2  ALTERNATIVES TO THE PROPOSED ACTION

5.2.1  Use of Steel Barge or Barges

5.2.1.1  Potential environmental impacts

	Experience in the Arctic has shown that steel barges can be used
successfully for long periods (Voelker et al. 1991).  A life time of 30
years or more is a reasonable expectation.  These barges generally have
no special ice-strengthened features, and operators report that "nothing
dramatic ever happens as a result of the freezing-in process."  Barges
that have been used in the Arctic environment include single-skinned
river fuel barges, light-shelled seismic vessels, and double-skinned,
heavily constructed icebreaking barges.  In the Arctic, the main concern
is not from the freezing-in process, but rather from the danger of the
barge being swept away with the ice during ice breakup.  Careful
selection of the location for freezing-in the barges is needed to ensure
that they are securely moored.

	Under this alternative, the barge would be towed to Antarctica from its
construction site or point of acquisition.  On at least one past
occasion, a fuel barge was towed to Antarctica by an icebreaker that was
making its annual roundtrip to support the USAP.  There was a
significant reduction in cruising speed (from 12 knots to 2–4 knots)
and transit time for the icebreaker.  Careful planning would be required
to avoid effects on icebreaker-supported activities such as refueling of
Marble Point and support of science.  Possibilities for avoiding such
impacts would be to obtain a longer period of support from the U.S.
Coast Guard, possibly arrange to have two icebreakers available, or have
the barge or barges towed by a commercially chartered seagoing tug. 
Environmental impacts from towing the barge would be primarily include
an increased amount of fuel used by the icebreaker.  

	Although the barge or barges would be designed for low maintenance,
replenishment of the deck coating or non-skid surface would be required
on an annual basis, and repair of minor structural damage associated
with normal usage of the barge would be needed periodically.  No
requirement of periodic dry docking is anticipated, and should
significant structural damage to the barge occur, it could probably be
towed to a drydock in New Zealand for repair.  Periodically, the deck
surface material would be replaced.  (It is possible another type of
deck surface would be used.)  Because the deck coating would be procured
in the United States and then transported to Antarctica, the current
practice of acquiring earth materials in the McMurdo area for spreading
on the working surface of the ice wharf would no longer be required, and
the already minimal impacts associated with collection of these
materials would be reduced.  Environmental impacts from maintenance
activities are likely to be both less than minor and transitory.

	Heated storage would be required for the fenders used between the barge
and vessels tieing up to the wharf.  Such storage could result in
impacts of building a new storage facility, but existing storage may be
available.

	It is possible that some dredging would be needed in the area where the
barge or barges would be anchored.  This could create adverse impact
because contaminated bottom sediments (NSF 1991) would be disturbed and
perhaps remobilized.  Unique benthic communities (NSF 1991) could be
disturbed or destroyed by dredging.  However, this area is already
highly disturbed and the sediments contaminated with hydrocarbons.  To
the extent possible, dredging would be avoided.  The barge may require
seabed anchors to keep it in place, which could also result in
disturbance of bottom sediments and communities.  This potential impact
should be minimal because of the localized disturbance.

5.2.1.2  Recommendations

	The following recommendations contained in Voelker et al. (1991) should
be implemented if a final design for using a steel barge or barges to
replace the ice wharf is pursued:

1.Acquire additional monthly data on ice thickness in the immediate
vicinity of and adjacent to the ice wharf site at Winter Quarters Bay
and obtain a series of ice cores in this area to estimate ice strength. 
This information would be used to evaluate if the deterioration of the
ice piers is related in part to the wastewater discharge that occurs
within about 150 m of the site.  More information on the bottom contours
and substrate conditions is also needed.  If it appears that dredging is
needed to allow a barge to be used, a detailed mitigation plan should be
developed to ensure that any adverse impacts from the dredging operation
and the resulting spoils are minimized.

2.Explore the acquisition and use of existing equipment from Arctic
operations.  The suitability of such equipment would need to be
evaluated carefully.  If an existing barge or barges could be obtained,
considerable time and expense could be saved and additional capabilities
(e.g., having cranes, work areas, or berthing capabilities) might be
possible.

3.Examine the possibility of mooring the barge farther from the shore to
eliminate the need for shore-side fenders.

4.Determine if improved methods of deploying oil spill retention booms
could be incorporated into the design of the barge.

5.Evaluate the possibility of carrying cargo on the barge when it is
towed to McMurdo.  Such transport could free up space on the annual
resupply vessel for other materials, equipment, and supplies.  If
schedules could be coordinated, delivery of materials needed for the
construction of the new South Pole Station could be expedited.

6.Determine the need to develop some type of cable or chain to draw
across the bay to protect the barge from icebergs.

	6.  FINDINGS

	The proposed construction of ice wharves at McMurdo Station would
result in both less than minor or transition impacts.  Construction of
the replacement ice wharf would require steel cables, steel pipe, and
wooden poles that are incorporated into the ice structure.  Use of the
wharf would require annual collection of earth materials that would be
applied to the surface of the wharf immediately before it is used each
season.  Although such materials are scraped from the wharf surface at
the end of each year and stockpiled for future use, a considerable
quantity of these materials become embedded in the ice structure and are
not recoverable.  The surface of the ice wharf may become contaminated
with minor spills of petroleum products from the operation of heavy
equipment and the transfer of fuel from the tanker.  Although such
spills would be cleaned up to the extent feasible, some residual
contamination could be retained in the ice wharf structure.  The useful
life of the ice wharf is uncertain.  Although attempts are being made to
improve the design so that the wharf would have an extended life,
history to date indicates that an average of four years is to be
expected because the underlying ice deteriorates and cracks form to the
point that the structure begins to break up.  At the end of its useful
life, therefore, the wharf would be towed to sea and released.  After
the wharf is set adrift, the steel cable, imbedded earth materials, and
any contamination would gradually be released to the ocean.  The
environmental impacts of this disposal are considered to be negligible
because they occur very gradually and the resulting contamination
levels, if any, would be very small.

	Reasons for ice wharf failure or longevity are not well understood. 
The fewer wharves that are built the less materials must be used and
eventually disposed of.  It is therefore suggested that the following
recommendations be considered for implementation.  Some of these
recommendations are aimed at using the wharves as a laboratory to
increase our understanding of ice stress and failure in order to
increase the life of future wharves, if they are built.  These
recommendations are:

1.Perform theoretical analysis or wave flexure in a floating ice wharf,
measurement of the ice properties in the wharf, determination of local
bathymetry, and monitoring of water motion and ice reflection during the
open-water season should be done.

2.Use the proposed McMurdo snow and ice laboratory or suitable
institution for the study of ice wharves.

3.   Evaluate the effects of the McMurdo heated wastewater discharge on
ice wharves.

     

	A substantial effort should also be made to avoid the cracking of the
ice wharf during sea ice breakout by the icebreakers.  Historically this
seems to be the single greatest reason for wharf failure.  Combinations
of trenching and blasting just prior to ice breakout should continue to
be explored as preventive measures.  

	Obtaining twenty (20) 10.0 gram samples of the surface material and
evaluation of those samples for possible contamination is necessary to
detect and to limit the potential spread of any contaminants. 
Evaluation of these samples must be done prior to reuse of the surface
materials.

	The use of a steel barge or barges to replace the ice wharf has many
potential advantages.  Based on experience with barges in the Arctic, a
barge or barges may have a 30-year or longer life.  If a barge or barges
were to be used for the wharf, construction activities currently
required each winter season for the ice wharf would no longer be needed,
resulting in fewer (approximately 6) workers needed in the winter-over
crew.  There is a possibility that mooring the barges to the shore at
Winter Quarters Bay would require dredging.  Dredging could result in
adverse environmental impacts by release of contaminated materials
(e.g., PCBs and residual petroleum products) from the substrate and
disturbance or destruction of unique bottom communities.  The barge or
barges would require low maintenance, consisting primarily of periodic
resurfacing of the deck, tanks, and sides.  Each year the barges tanks
would need to be ballasted to limit potential damage from freezing and
ice.  If diesel fuel could be used to ballast these tanks, the barge
would represent an additional fuel storage facility.  A risk analysis of
the potential of a fuel leak from the ballast tanks would be required
before this option was pursued.  Other possibilities for ballast are
available.  Use of a single barge would limit the size of the work area
and would probably require the development of a conveyer or boom system
to move cargo to and from the shore.  Use of two or four barges would
require additional studies of the effects of ice buildup between the
barges and their ability to resist damage from unequal distribution of
weight during cargo transfer.  Use of steel barges is not a viable
option for the 1992–93 season, but it should be given serious
consideration for implementation in the future.  USAP will conduct
additional environmental review should this alternative be pursued.

	Other alternatives that were considered were a permanent pier, an ice
dock, and the no action alternative of using sea ice as a docking
facility. These alternatives were dismissed because they did not seem to
be practical and/or there were major safety concerns.

	7.  LITERATURE CITED

Barry, J. B., and P. K. Dayton.  1988.  "Current patterns in McMurdo
Sound, Antarctica, and their implications for productivity of local
benthic communities."  Polar Biology 8:367–376.

Dayton, P. K. and G. A. Robilliard.  1971.  "Implications of pollution
to the McMurdo Sound benthos."  Antarctic Journal of the United States
8:53–56.

Hoffman, C. R.  1979.  Engineering Manual for McMurdo Station.  Civil
Engineering Laboratory, Port Hueneme, California.

Lenihan, H. S., J. S. Oliver, J. M. Oakden, and M. D. Stephenson.  1990.
 "Intense and localized benthic marine pollution around McMurdo Station,
Antarctica."  Marine Pollution Bulletin 21(9):422–430.

National Science Foundation (NSF).  1991.  Final Supplemental
Environmental Impact Statement for the U.S. Antarctic Program.  Division
of Polar Programs, Washington, D.C.

Naval Support Force Antarctica (NSFA).  1981.  Report of Operation Deep
Freeze 81, 1980–81.  U.S. Navy, COMNAVSUPPFORANTARCTICA, Port Hueneme,
California.

Naval Support Force Antarctica (NSFA).  1984.  Report of Operation Deep
Freeze 84, 1983–84.  U.S. Navy, COMNAVSUPPFORANTARCTICA, Port Hueneme,
California.

Naval Support Force Antarctica (NSFA).  1990.  Report of Operation Deep
Freeze 1989–90.  U.S. Navy, COMNAVSUPPFORANTARCTICA, Port Hueneme,
California.

Risebrough, R. W., B. W. DeLappe, and C. Younghans-Haug.  1990.  "PCB
and PCT contamination in Winter Quarters Bay, Antarctica."  Marine
Pollution Bulletin 21(11):523-529.

Voelker, R. P., P. V. Minnick, L. A. Schultz, and J. W. St. John. 1991. 
Conceptual Design and Cost of a Steel Barge to Replace the Ice Pier at
McMurdo, Antarctica.  Draft Report submitted to the Division of Polar
Programs, National Science Foundation, Washington, D.C.

	8.  LIST OF PREPARERS

NATIONAL SCIENCE FOUNDATION, DIVISION OF POLAR PROGRAMS 

Dr. Sidney Draggan, Environmental Officer

OAK RIDGE NATIONAL LABORATORY

R. B. McLean, Ph.D., Marine Biology, Florida State University; B.A.,
Biology, Florida State University; 18 years' experience in environmental
assessment.

R. M. Reed, Ph.D., Botany/Plant Ecology, Washington State University;
A.B., Botany, Duke University; 18 years' experience in environmental
assessment.

     Voelker et al. (1991) note that the term ice wharf and ice pier are
synonymous in the context of the McMurdo facility.  The term ice wharf
is used here for consistency.

     The term retrograde is used by USAP to indicate the process of
returning any items (e.g., wastes materials, and scientific samples) to
the United States or other countries for disposal, recycling, or reuse.

 

 

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