1. Strategies to manage human activity in the tundra 5

2. 5. Trans-Alaska Pipeline System The Trans-Alaska Pipeline System (TAPS), usually called the Alyeska Pipeline in Alaska or the Alaska Pipeline elsewhere, is a major U.S. oil pipeline connecting oil fields in Alaska's North Slope to a North Pacific seaport where the oil can be shipped to the Lower 48 states for refining. The main Trans-Alaska Pipeline runs north to south, almost 800 miles (1,300 km), from the Arctic Ocean at Prudhoe Bay, Alaska to the Gulf of Alaska at Valdez, Alaska, passing near several Alaskan villages and towns, including Wiseman (pop. 21), Bettles (pop.39), Livengood (pop.29), Fox (pop.300), Fairbanks (pop. 34,540), and Glennallen (pop.554)

3. Construction of the pipeline through the sparsely-populated region presented significant challenges due to the difficult terrain and the harsh environment along the route. Between the North Slope and Valdez, there were three mountain ranges, active fault lines, miles of unstable, boggy ground underlain with frost, hundreds of streams and rivers, and migration paths of caribou and moose. Deer and elk are also affected by the construction. Geological activity has damaged the pipeline on several occasions. Since its completion in 1977, the pipeline has transported over 15 billion barrels (2.4 TL) of oil. Opposition Opposition to construction of the pipeline came from two primary sources: Alaska Native groups and conservationists. Alaska Natives were upset that the pipeline would cross land traditionally claimed by a variety of groups but would not contribute economically to those groups. Conservationists were angry at what they saw as an incursion into America's last wilderness. Both opposition movements launched legal campaigns to halt the pipeline and were successful in preventing construction from 1970 to 1973.

4. Although conservation groups and environmental organizations voiced opposition to the pipeline project before 1970, the introduction of the National Environmental Policy Act allowed them legal grounds to halt the project. Arctic engineers had raised concerns about the way plans for a subterranean pipeline showed ignorance of Arctic engineering and permafrost in particular. A clause in NEPA requiring a study of alternatives and another clause requiring an environmental impact statement turned those concerns into tools used by the Wilderness Society, Friends of the Earth, and the Environmental Defense Fund in their spring 1970 lawsuit to stop the project. Due to the injunction against the project, Alyeska was forced to do further research throughout the summer of 1970. The collected material was turned over to the Interior Department in October 1970, and a draft environmental impact statement was published in January 1971. The statement met with massive criticism from almost the moment it was released. The statement amounted to 294 pages but generated more than 12,000 pages of testimony and evidence in Congressional debates by the end of March. Criticisms of the project included its effect on the Alaska tundra, possible pollution, harm to animals, geographic features, and the lack of much engineering information from Alyeska. One element of opposition the report quelled was the discussion of alternatives. All the proposed alternatives—extension of the Alaska Railroad, an alternative route through Canada, establishing a port at Prudhoe Bay, and more—were deemed to pose more environmental risks than construction of a pipeline directly across Alaska Conservation objections

5. Opposition also was directed at the building of the construction and maintenance highway parallel to the pipeline. Although a clause in Alyeska's pipeline proposal called for removal of the pipeline at a certain point, no such provision was made for removal of the road. Sydney Howe, president of the Conservation Foundation, warned: "The oil might last for fifty years. A road would remain forever." This argument relied upon the slow growth of plants and animals in far northern Alaska due to the harsh conditions and short growing season. In testimony, an environmentalist argued that arctic trees, though only a few feet tall, had been seedlings "when George Washington was inaugurated“. The portion of the environmental debate with the biggest symbolic impact took place when discussing the pipeline's impact on caribou herds. Environmentalists proposed that the pipeline would have an effect on caribou similar to the effect of the U.S. transcontinental railroad on the American Bison population of North America. Pipeline critics said the pipeline would block traditional migration routes, making caribou populations smaller and making them easier to hunt. This idea was exploited in anti- pipeline advertising, most notably when a picture of a forklift carrying several legally shot caribou was emblazoned with the slogan, "There is more than one way to get caribou across the Alaska Pipeline". The use of caribou as an example of the pipeline's environmental effects reached a peak in the spring of 1971, when the draft environmental statement was being debated

6. Native objections In 1902, the United States Department of Agriculture set aside 16,000,000 acres (64,750 km 2 ) of Southeast Alaska as the Tongass National Forest. Tlingit natives who lived in the area protested that the land was theirs and had been unfairly taken. In 1935, Congress passed a law allowing the Tlingits to sue for recompense, and the resulting case dragged on until 1968, when a $7.5 million settlement was reached. Following the Native lawsuit to halt work on the Trans-Alaska Pipeline, this precedent was frequently mentioned in debate, causing pressure to resolve the situation more quickly than the 33 years it had taken for the Tlingits to be satisfied. Between 1968 and 1971, a succession of bills were introduced into the U.S. Congress to compensate statewide Native claims. The earliest bill offered $7 million, but this was flatly rejected. The Alaska Federation of Natives, which had been created in 1966, hired former United States Supreme Court justice Arthur Goldberg, who suggested that a settlement should include 40 million acres of land and a payment of $500 million. The issue remained at a standstill until Alyeska began lobbying in favor of a Native claims act in Congress in order to lift the legal injunction against pipeline construction. In October 1971, President Richard Nixon signed the Alaska Native Claims Settlement Act. Under the act, Native groups would renounce their land claims in exchange for $962.5 million and 148,500,000 acres (601,000 km 2 ) in federal land. The money and land were split up among village and regional corporations, which then distributed shares of stock to Natives in the region or village. The shares paid dividends based on both the settlement and corporation profits

7. The trans-Alaska pipeline stretches from the northern settlement of Prudhoe Bay on the Arctic Ocean, across the Brooks, Alaska, and Chugach mountain ranges, to Port Valdez on the state's southern coast. Half of the 799-mile pipeline is buried and half rests on supports aboveground, to avoid permafrost melting that can lead to structural and environmental damage. Up to two million barrels of crude oil are pumped through the four-foot diameter pipeline daily, cooling from an average temperature of 49 degrees Celsius at Prudhoe Bay to about 21 degrees Celsius at Port Valdez. Protected from subzero temperatures by a heated tent-like structure, workers take detailed measurements of corroded sections of pipe using grids that allow a map of the area to be developed for integrity assessment analyses. The measurements are compared with those estimated by a smart pig and then analyzed to determine the remaining strength of the corroded region.

8. Construction The oil companies with exploration rights grouped together as the Alyeska consortium to create a company, the Alyeska Pipeline Service Company, to design, build, and then operate the pipeline. US President Richard Nixon signed the Trans-Alaska Pipeline Authorization Act into law on 16 November 1973, which authorized the construction of the pipeline. The single 48 inch (1.22 m) diameter pipeline was built between 27 March 1975 to 31 May 1977 at a cost of about $8 billion. [31] The pipeline was constructed in six sections by five different contractors employing 21,000 people at the peak of work; 31 workers died in construction accidents. The 800-mile (1,286 km) route presented special challenges. As well as the harsh environment, the need to cross three mountain ranges and many rivers and streams, the permafrost of Alaska meant that more than half of the pipeline's length had to be elevated rather than buried as normal to prevent the ground melting and shifting. There were five years of surveying and geological sampling before construction began. During construction archaeological teams were repeatedly called in to investigate previously unknown sites which were disturbed by excavation. The pipeline crossing the Tanana River

9. Technical details Along the pipeline there are eleven pump stations, each with four pumps. Each electric pump is powered by diesel or natural gas generators. Twelve pump stations were planned but Pump Station 11 was never built, though the southward numbering system for the pump stations retains a place for this nonexistent station. Usually only around seven stations are active at one time, and plans to replace the existing pumps with newer high-efficiency pumps may reduce the number of active stations even further. The pipeline was built above ground in areas where thaw-sensitive permafrost exists. Where the line must be buried, such as highway crossings or avalanche-prone areas, the pipe is encased in an insulated, refrigerated ditch. Nearby refrigeration plants pump cold brine through 6 inch (15 cm) pipes which absorb heat and keep the soil cooled. Other areas of burial are either conventional covered ditches or unrefrigerated but insulated ditches, depending on the sensitivity of the surrounding soil. View of the pipeline's underside, heat pipes, and heat exchangers

10. Oil emerges from the ground at up to 180 °F (80 °C), and travels through the pipeline at temperatures above 120 °F (50 °C). In some elevated portions, heat conduction from the oil through the Vertical Support Members (VSMs) would melt the permafrost in which the VSMs are embedded. This would cause the pipeline to sink and possibly sustain damage. To prevent this, these portions of the pipeline include heat exchangers atop each VSM, passively cooled by convection to the air. Each heat exchanger is thermally coupled by a heat pipe to the base of the VSM. Running through the VSM, the heat pipe transports heat from the base to the heat exchanger. Since ammonia, the working fluid in the heat pipes, has a freezing point lower than the permafrost, the heat pipe works throughout the year, even during the coldest winter nights. This convection cooling system is thought by TAPS engineers to be the greatest innovation associated with the pipeline. Another innovation associated with the pipline is the zig-zag configuration aboveground. Since pipe shifts around far more easily aboveground than when buried, the zig-zag path of the pipeline allows the pipe to move from side to side and lengthwise. This movement may be caused by earthquakes or by thermal expansion and contraction. The VSMs also include "shoes" to allow for horizontal or lateral movement, and crushable blocks to absorb shocks from earthquakes, avalanches, or vehicles. Oil began flowing on 20 June 1977. Since then over 15 billion barrels (2.4×10 9 m 3 ) of oil have been pumped, peaking at 2.1 million barrels per day (330,000 m³/d) in 1988 and currently down to 720,000 barrels per day (114,000 m³/d) (April 2008 average). Around 16,700 tankers had been loaded at the Marine Terminal at Valdez by 2001. The terminal has berths for four tankers and cost almost US$1.4 billion to build. The first tanker to leave the terminal was the ARCO Juneau on 1 August 1977.

11. Maintenance The pipeline is surveyed several times a day, mostly by air. Due to the placement of the surveillance bases, the pipeline can be surveyed in just two hours, but most surveys take longer to ensure thoroughness. Other methods of surveying include regular pipeline inspection gauges ("pigs"), sent through the line. Some pigs are used to remove the buildup of kerosene inside the pipe, while others have electronics which relay radar scans and fluid measurements as they travel. The pipeline has been damaged several times. It was built with earthquakes in mind and has survived several, including the 7.9 magnitude quake of 3 November 2002. It is vulnerable to intentional attack and to forest fires. The highest losses from the pipeline were in February 1978, when a deliberate explosion led to more than 16,000 barrels (2,500 m³) leaking out at Steele Creek, near Fairbanks. From 1977 to 1994 there were 30 to 40 spills a year on average. The worst years in terms of number of incidents were 1991 to 1994, when there were 164 spills, although none were major. Since 1995 the number of spills has been sharply reduced, with total losses from 1997 to 2000 totalling only 6.89 barrels (1.10 m³). The steel pipe is resistant to gunshots, but on 4 October 2001, a drunken gunman named Daniel Carson Lewis shot a hole into a weld near Livengood, causing a spill of about 6,000 barrels (950 m 3 ). Approximately 2 acres (8,100 m 2 ) of tundra were soiled and were removed in the cleanup. The pipeline was repaired and was restarted on 7 October 2001. Lewis, known as a troublemaker in the community of fewer than 30 people, was apprehended four hours after the shooting. He was convicted on multiple state and federal felony charges, including a $10,000 fine and 10-year federal sentence for being a felon in possession of a firearm. In August 2006, after an inspection mandated by the United States Department of Transportation after a March spill, BP announced they had discovered corrosion severe enough to require replacement of 16 of 22 miles (35 km) of transit pipelines at their Prudhoe Bay oil field. No part of the main Trans-Alaska Pipeline was affected, although Alyeska said that lower crude oil volumes could slow pumping during the BP shutdown.

12. Pipeline on slider supports where it crosses the Denali Fault.