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- **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 Wa shington, D.C.

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iii **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 Con struction ................................ .............. 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

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iv **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

### ICE WHARF IEE May 1992

-vv **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 Prog ram (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 1 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 Initi al 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

1Voelker et al. (1991) note that the term ice wharfand ice pier are synonymous in the context of the McMurdo facility. The term ice wharfis used here for consistency.

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vi 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

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vii **Figure 1. McMurdo Sound an d vicinity.** 

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viii 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 pot ential 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, a nd 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** 

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

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- x x **Figure 2. McMurdo Station facilities.**

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xi

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xii for loading wastes and other materials to be retrogr aded2 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. **Table 1. History o f 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 pr obably 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.

2The 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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xiii 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.

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xiv 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 t o 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 wi th 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 19 92, 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.

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- xvxv (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 t he wharf (6.7

– 7.9 m) before it is used in January.

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xvi

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xvii **Figure 3. Schematic (not to scale) of 1990 ice wharf in Winter Quarters**

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xviii **Bay, McMurdo Station, Antarctica.**

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xix **Table 2. Types and quantities of materials used during constr uction 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 yd 3 (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 l iters
(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 r econstruction 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 conta in 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 expe cted 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

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- xx xx 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. T he finished thickness of the wharf is planned to be 6.1 to 6.7 m. Lighting for the

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xxi Figure 4

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xxii Figure 5

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xxiii **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 surfac e 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

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xxiv 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 su rface 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 N SFA 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 pl an 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 do cked 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.) deto nation 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**

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- xxvxxv 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 conti nue 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.

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xxvi **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 const ructed 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 patte rned 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.

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xxvii 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 sh orefront 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 s everal 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 p ermanent 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 Qua rters 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

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xxviii 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 ic e 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 (Fi g. 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.

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xxix 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 enclose s 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 th e 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

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- xxx xxx 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 tha t 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 actio n 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 t he 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 cha rges 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** 

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xxxi 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. T hese 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 barge s, 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. C areful 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 occasio n, 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 woul d 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 t o 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 r equirement 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.

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xxxii Heated stor age 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 ne eded 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 destro yed 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 dis turbance 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 are a 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.

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xxxiii 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 ba rge 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 pole s 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 petrole um 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 b e released to the ocean. The environmental impacts of this disposal are considered to be negligible

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xxxiv 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, me asurement 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 w inter 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 cou ld result in adverse environmental impacts by

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- xxxvxxxv 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 repre sent 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 enviro nmental 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 Biolo gy **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 Laborator y, 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.

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xxxvi National Science Foundatio n (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, COMNAVS UPPFORANTARCTICA, 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.

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xxxvii **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., B iology, 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.