United States Census Bureau
The United States Census Bureau is a principal agency of the U. S. Federal Statistical System, responsible for producing data about the American people and economy; the Census Bureau is part of the U. S. Department of Commerce and its director is appointed by the President of the United States; the Census Bureau's primary mission is conducting the U. S. Census every ten years, which allocates the seats of the U. S. House of Representatives to the states based on their population; the Bureau's various censuses and surveys help allocate over $400 billion in federal funds every year and it helps states, local communities, businesses make informed decisions. The information provided by the census informs decisions on where to build and maintain schools, transportation infrastructure, police and fire departments. In addition to the decennial census, the Census Bureau continually conducts dozens of other censuses and surveys, including the American Community Survey, the U. S. Economic Census, the Current Population Survey.
Furthermore and foreign trade indicators released by the federal government contain data produced by the Census Bureau. Article One of the United States Constitution directs the population be enumerated at least once every ten years and the resulting counts used to set the number of members from each state in the House of Representatives and, by extension, in the Electoral College; the Census Bureau now conducts a full population count every 10 years in years ending with a zero and uses the term "decennial" to describe the operation. Between censuses, the Census Bureau makes population projections. In addition, Census data directly affects how more than $400 billion per year in federal and state funding is allocated to communities for neighborhood improvements, public health, education and more; the Census Bureau is mandated with fulfilling these obligations: the collecting of statistics about the nation, its people, economy. The Census Bureau's legal authority is codified in Title 13 of the United States Code.
The Census Bureau conducts surveys on behalf of various federal government and local government agencies on topics such as employment, health, consumer expenditures, housing. Within the bureau, these are known as "demographic surveys" and are conducted perpetually between and during decennial population counts; the Census Bureau conducts economic surveys of manufacturing, retail and other establishments and of domestic governments. Between 1790 and 1840, the census was taken by marshals of the judicial districts; the Census Act of 1840 established a central office. Several acts followed that revised and authorized new censuses at the 10-year intervals. In 1902, the temporary Census Office was moved under the Department of Interior, in 1903 it was renamed the Census Bureau under the new Department of Commerce and Labor; the department was intended to consolidate overlapping statistical agencies, but Census Bureau officials were hindered by their subordinate role in the department. An act in 1920 changed the date and authorized manufacturing censuses every two years and agriculture censuses every 10 years.
In 1929, a bill was passed mandating the House of Representatives be reapportioned based on the results of the 1930 Census. In 1954, various acts were codified into Title 13 of the US Code. By law, the Census Bureau must count everyone and submit state population totals to the U. S. President by December 31 of any year ending in a zero. States within the Union receive the results in the spring of the following year; the United States Census Bureau defines four statistical regions, with nine divisions. The Census Bureau regions are "widely used...for data collection and analysis". The Census Bureau definition is pervasive. Regional divisions used by the United States Census Bureau: Region 1: Northeast Division 1: New England Division 2: Mid-Atlantic Region 2: Midwest Division 3: East North Central Division 4: West North Central Region 3: South Division 5: South Atlantic Division 6: East South Central Division 7: West South Central Region 4: West Division 8: Mountain Division 9: Pacific Many federal, state and tribal governments use census data to: Decide the location of new housing and public facilities, Examine the demographic characteristics of communities and the US, Plan transportation systems and roadways, Determine quotas and creation of police and fire precincts, Create localized areas for elections, utilities, etc.
Gathers population information every 10 years The United States Census Bureau is committed to confidentiality, guarantees non-disclosure of any addresses or personal information related to individuals or establishments. Title 13 of the U. S. Code establishes penalties for the disclosure of this information. All Census employees must sign an affidavit of non-disclosure prior to employment; the Bureau cannot share responses, addresses or personal information with anyone including United States or foreign government
A geologic map or geological map is a special-purpose map made to show geological features. Rock units or geologic strata are shown by color or symbols to indicate where they are exposed at the surface. Bedding planes and structural features such as faults, folds and lineations are shown with strike and dip or trend and plunge symbols which give these features' three-dimensional orientations. Stratigraphic contour lines may be used to illustrate the surface of a selected stratum illustrating the subsurface topographic trends of the strata. Isopach maps detail the variations in thickness of stratigraphic units, it is not always possible to properly show this when the strata are fractured, mixed, in some discontinuities, or where they are otherwise disturbed. Rock units are represented by colors. Instead of colors, certain symbols can be used. Different geologic mapping agencies and authorities have different standards for the colors and symbols to be used for rocks of differing types and ages. Geologists take two major types of orientation measurements: orientations of planes and orientations of lines.
Orientations of planes are measured as a "strike" and "dip", while orientations of lines are measured as a "trend" and "plunge". Strike and dip symbols consist of a long "strike" line, perpendicular to the direction of greatest slope along the surface of the bed, a shorter "dip" line on side of the strike line where the bed is going downwards; the angle that the bed makes with the horizontal, along the dip direction, is written next to the dip line. In the azimuthal system and dip are given as "strike/dip". Trend and plunge are used for linear features, their symbol is a single arrow on the map; the arrow is oriented in the downgoing direction of the linear feature and at the end of the arrow, the number of degrees that the feature lies below the horizontal is noted. Trend and plunge are notated as PLUNGE → TREND; the oldest preserved geologic map is the Turin papyrus, which shows the location of building stone and gold deposits in Egypt. The earliest geologic map of the modern era is the 1771 "Map of Part of Auvergne, or figures of, The Current of Lava in which Prisms, Etc. are Made from Basalt.
To be used with Mr. Demarest's theories of this hard basalt. Engraved by Messr. Pasumot and Daily, Geological Engineers of the King." This map is based on Nicolas Desmarest's 1768 detailed study of the geology and eruptive history of the Auvergne volcanoes and a comparison with the columns of the Giant's Causeway of Ireland. He identified both landmarks as features of extinct volcanoes; the 1798 report was incorporated in the 1771 Royal Academy of Science compendium. The first geological map of the U. S. was produced in 1809 by William Maclure. In 1807, Maclure undertook the self-imposed task of making a geological survey of the United States, he mapped nearly every state in the Union. During the rigorous two-year period of his survey, he crossed and recrossed the Allegheny Mountains some 50 times. Maclure's map shows the distribution of five classes of rock in what are now only the eastern states of the present-day US; the first geologic map of Great Britain was created by William Smith in 1815 using principles first formulated by Smith.
In the United States, geologic maps are superimposed over a topographic map with the addition of a color mask with letter symbols to represent the kind of geologic unit. The color mask denotes the exposure of the immediate bedrock if obscured by soil or other cover; each area of color denotes a geologic unit or particular rock formation. However, in areas where the bedrock is overlain by a thick unconsolidated burden of till, terrace sediments, loess deposits, or other important feature, these are shown instead. Stratigraphic contour lines, fault lines and dip symbols, are represented with various symbols as indicated by the map key. Whereas topographic maps are produced by the United States Geological Survey in conjunction with the states, geologic maps are produced by the individual states. There are no geologic map resources for some states, while a few states, such as Kentucky and Georgia, are extensively mapped geologically. In the United Kingdom the term geological map is used; the UK and Isle of Man have been extensively mapped by the British Geological Survey since 1835.
Two 1:625,000 scale maps cover the basic geology for the UK. More detailed sheets are available at scales of 1:250,000, 1:50,000 and 1:10,000; the 1:625,000 and 1:250,000 scales show both onshore and offshore geology, whilst other scales cover exposures on land only. Sheets of all scales fall into two categories: Superficial deposit maps show both bedrock and the deposits on top of it. Bedrock maps show the underlying rock, without superficial deposits; the maps are superimposed over a topographic map base produced by Ordnance Survey, use symbols to represent fault lines and dip or geological units, boreholes etc. Colors are used to represent different geological units. Explanatory booklets (
Fort Yukon, Alaska
Fort Yukon is a city in the Yukon-Koyukuk Census Area in the U. S. state of Alaska. The population, predominately Gwich'in Alaska Natives, was 583 at the 2010 census, down from 595 in 2000. Fort Yukon is the hometown of Alaska Congressman Don Young. Served by Fort Yukon Airport, it is known for having the record highest temperature in Alaska; this area north of the Arctic Circle was occupied for thousands of years by cultures of indigenous people and in historic times by the Gwich’in people. What became the village of Fort Yukon developed from a trading post, Fort Yukon, established by Alexander Hunter Murray of the Hudson's Bay Company, on 25 June 1847. Murray drew numerous sketches of fur trade posts and of people and wrote the Journal of the Yukon, 1847–48, which gave valuable insight into the culture of the Gwich’in at the time. While the post was in Russian America, the Hudson's Bay Company continued to trade there until the American traders expelled it in 1869, following the Alaska Purchase when the Alaska Commercial Company took over the post.
During the Klondike Gold Rush, in the winter of 1897–1898, Fort Yukon received two hundred prospectors from Dawson City, short of supply. A post office was established on July 1898 with John Hawksly as its first postmaster; the settlement suffered over the following decades as a result of several infectious disease epidemics and a 1949 flood. During the 1950s, the United States Air Force established a radar station at Fort Yukon. Since the late 20th century, due in part to its extreme northerly location and its proximity to Fairbanks, it has become a minor tourist destination. On February 7, 1984 a Terrier Malemute-type sounding rocket, with a maximum altitude of 310 miles, was launched from Fort Yukon. Fort Yukon is located at 66°34′2″N 145°15′23″W. Fort Yukon is located on the north bank of the Yukon River at its junction with the Porcupine River, about 145 miles northeast of Fairbanks. According to the United States Census Bureau, the city in Northeastern Alaska has a total area of 7.4 square miles, of which, 7.0 square miles of it is land and 0.4 square miles of it is water.
It is located 8 miles north of the Arctic Circle, at the confluence of the Yukon and Porcupine Rivers and in the middle of the Yukon Flats. The highest temperature recorded in Alaska occurred in Fort Yukon on June 27, 1915, when it reached 100 °F or 37.8 °C. Until 1971, Fort Yukon held the all-time lowest temperature record at −78 °F or −61.1 °C, it still holds the record for the lowest mean monthly temperature when the notoriously cold month of December 1917 had an average daily temperature of −48.3 °F or −44.6 °C and the minimum averaged −58 °F or −50 °C. The climate regime is a strong continental subarctic climate with severe winters, being less influenced by chinook winds than areas to the west – the winter season absolute maximum being 17 °F or 9.4 °C colder than in Fairbanks. Summer temperatures are exceptionally high for such a northerly area, being far warmer than the tree line threshold. In the Summer Fort Yukon has midnight sun and in December there is no sun at all. Fort Yukon first appeared on the 1880 U.
S. Census as an unincorporated village of 109 residents. Of those, 107 were members of the Tinneh Tribe and 2 were Whites, it did not appear on the 1890 census, but has returned in every successive census since 1900. It formally incorporated in 1959, the year Alaska became a state; as of the census of 2000, there were 595 people, 225 households, 137 families residing in the city. The population density was 85.0 people per square mile. There were 317 housing units at an average density of 45.3 per square mile. The racial makeup of the city was 86.05% Native American, 10.76% White, 0.17% Black or African American, 0.17% Asian, 0.17% from other races, 2.69% from two or more races. Hispanic or Latino of any race were 1.34% of the population. There were 225 households out of which 36.0% had children under the age of 18 living with them, 25.8% were married couples living together, 23.1% had a female householder with no husband present, 39.1% were non-families. 34.2% of all households were made up of individuals and 5.8% had someone living alone, 65 years of age or older.
The average household size was 2.62 and the average family size was 3.37. In the city, the population was spread out with 33.4% under the age of 18, 10.3% from 18 to 24, 27.4% from 25 to 44, 22.0% from 45 to 64, 6.9% who were 65 years of age or older. The median age was 32 years. For every 100 females, there were 112.5 males. For every 100 females age 18 and over, there were 111.8 males. The median income for a household in the city was $29,375, the median income for a family was $32,083. Males had a median income of $25,000 versus $27,813 for females; the per capita income for the city was $13,360. About 18.0% of families and 18.5% of the population were below the poverty line, including 14.3% of those under age 18 and 3.5% of those age 65 or over. Yukon Flats School District operates the Fort Yukon School. Clarence Alexander Jonathon Solomon Velma Wallis Don Young Hudson Stuck Media related to Fort Yukon, Alaska at Wikimedia Commons
Per capita income
Per capita income or average income measures the average income earned per person in a given area in a specified year. It is calculated by dividing the area's total income by its total population. Per capita income is national income divided by population size. Per capita income is used to measure an area's average income and compare the wealth of different populations. Per capita income is used to measure a country's standard of living, it is expressed in terms of a used international currency such as the euro or United States dollar, is useful because it is known, is calculable from available gross domestic product and population estimates, produces a useful statistic for comparison of wealth between sovereign territories. This helps to ascertain a country's development status, it is one of the three measures for calculating the Human Development Index of a country. In the United States, it is defined by the U. S. Census Bureau as the following: "Per capita income is the mean money income received in the past 12 months computed for every man and child in a geographic area."
Critics claim that per capita income has several weaknesses in measuring prosperity: Comparisons of per capita income over time need to consider inflation. Without adjusting for inflation, figures tend to overstate the effects of economic growth. International comparisons can be distorted by cost of living differences not reflected in exchange rates. Where the objective is to compare living standards between countries, adjusting for differences in purchasing power parity will more reflect what people are able to buy with their money, it does not reflect income distribution. If a country's income distribution is skewed, a small wealthy class can increase per capita income while the majority of the population has no change in income. In this respect, median income is more useful when measuring of prosperity than per capita income, as it is less influenced by outliers. Non-monetary activity, such as barter or services provided within the family, is not counted; the importance of these services varies among economies.
Per capita income does not consider whether income is invested in factors to improve the area's development, such as health, education, or infrastructure. List of countries by average wage List of countries by GDP per capita—GDP at market or government official exchange rates per inhabitant List of countries by GDP per capita—GDP calculated at purchasing power parity exchange per inhabitant List of countries by GNI per capita List of countries by GNI per capita List of countries by income equality Total personal income
Gold is a chemical element with symbol Au and atomic number 79, making it one of the higher atomic number elements that occur naturally. In its purest form, it is a bright reddish yellow, soft and ductile metal. Chemically, gold is a group 11 element, it is solid under standard conditions. Gold occurs in free elemental form, as nuggets or grains, in rocks, in veins, in alluvial deposits, it occurs in a solid solution series with the native element silver and naturally alloyed with copper and palladium. Less it occurs in minerals as gold compounds with tellurium. Gold is resistant to most acids, though it does dissolve in aqua regia, a mixture of nitric acid and hydrochloric acid, which forms a soluble tetrachloroaurate anion. Gold is insoluble in nitric acid, which dissolves silver and base metals, a property that has long been used to refine gold and to confirm the presence of gold in metallic objects, giving rise to the term acid test. Gold dissolves in alkaline solutions of cyanide, which are used in mining and electroplating.
Gold dissolves in mercury, forming amalgam alloys. A rare element, gold is a precious metal, used for coinage and other arts throughout recorded history. In the past, a gold standard was implemented as a monetary policy, but gold coins ceased to be minted as a circulating currency in the 1930s, the world gold standard was abandoned for a fiat currency system after 1971. A total of 186,700 tonnes of gold exists above ground, as of 2015; the world consumption of new gold produced is about 50% in jewelry, 40% in investments, 10% in industry. Gold's high malleability, resistance to corrosion and most other chemical reactions, conductivity of electricity have led to its continued use in corrosion resistant electrical connectors in all types of computerized devices. Gold is used in infrared shielding, colored-glass production, gold leafing, tooth restoration. Certain gold salts are still used as anti-inflammatories in medicine; as of 2017, the world's largest gold producer by far was China with 440 tonnes per year.
Gold is the most malleable of all metals. It can be drawn into a monoatomic wire, stretched about twice before it breaks; such nanowires distort via formation and migration of dislocations and crystal twins without noticeable hardening. A single gram of gold can be beaten into a sheet of 1 square meter, an avoirdupois ounce into 300 square feet. Gold leaf can be beaten thin enough to become semi-transparent; the transmitted light appears greenish blue, because gold reflects yellow and red. Such semi-transparent sheets strongly reflect infrared light, making them useful as infrared shields in visors of heat-resistant suits, in sun-visors for spacesuits. Gold is a good conductor of electricity. Gold has a density of 19.3 g/cm3 identical to that of tungsten at 19.25 g/cm3. By comparison, the density of lead is 11.34 g/cm3, that of the densest element, osmium, is 22.588±0.015 g/cm3. Whereas most metals are gray or silvery white, gold is reddish-yellow; this color is determined by the frequency of plasma oscillations among the metal's valence electrons, in the ultraviolet range for most metals but in the visible range for gold due to relativistic effects affecting the orbitals around gold atoms.
Similar effects impart a golden hue to metallic caesium. Common colored gold alloys include the distinctive eighteen-karat rose gold created by the addition of copper. Alloys containing palladium or nickel are important in commercial jewelry as these produce white gold alloys. Fourteen-karat gold-copper alloy is nearly identical in color to certain bronze alloys, both may be used to produce police and other badges. White gold alloys can be made with nickel. Fourteen- and eighteen-karat gold alloys with silver alone appear greenish-yellow and are referred to as green gold. Blue gold can be made by alloying with iron, purple gold can be made by alloying with aluminium. Less addition of manganese, aluminium and other elements can produce more unusual colors of gold for various applications. Colloidal gold, used by electron-microscopists, is red. Gold has only one stable isotope, 197Au, its only occurring isotope, so gold is both a mononuclidic and monoisotopic element. Thirty-six radioisotopes have been synthesized, ranging in atomic mass from 169 to 205.
The most stable of these is 195Au with a half-life of 186.1 days. The least stable is 171Au. Most of gold's radioisotopes with atomic masses below 197 decay by some combination of proton emission, α decay, β+ decay; the exceptions are 195Au, which decays by electron capture, 196Au, which decays most by electron capture with a minor β− decay path. All of gold's radioisotopes with atomic masses above 197 decay by β− decay. At least 32 nuclear isomers have been characterized, ranging in atomic mass from 170 to 200. Within that range, only 178Au, 180Au, 181Au, 182Au, 188Au do not have isomers. Gold's most stable isomer is 198m2Au with a half-life of 2.27 days. Gold's least stable isomer is 177m2Au with a half-life of only 7 ns. 184m1Au has three decay paths: β+ decay, isomeric
Galena is a city in the Yukon-Koyukuk Census Area in the U. S. state of Alaska. At the 2010 census the population was 470, with a 2016 estimate of 488 inhabitants. Galena was established in 1918, a military airfield was built adjacent to the city during World War II; the city was incorporated in 1971. The Koyukon Athabascans moved as the wild game migrated. In the summer many families floated on rafts to the Yukon River to fish for salmon. There were 12 summer fish camps located on the Yukon River between the Koyukuk River and the Nowitna River. Galena was established in 1918 near an Athabascan fish camp called Henry's Point, it became a supply and point for nearby lead ore mines that opened in 1918 and 1919. In 1941 and 1942, during World War II, a military air field was built adjacent to the civilian airport, the two facilities shared the runway and flight line facilities; this air field was designated Galena Air Force Station shortly after the split of the United States Air Force from the United States Army, which occurred as a result of the National Security Act of 1947.
During the 1950s, the construction of additional military facilities at Galena and the nearby Campion Air Force Station, in support of Galena's mission as a forward operating base under the auspices of the 5072nd Air Base Group, headquartered at Elmendorf Air Force Base, near Anchorage, provided improvements to the airport and the local infrastructure, causing economic growth for the area. Following the end of the Cold War, in 1993, operation of Galena Air Force Station was turned over to a contractor, all military personnel were withdrawn with only small groups of active personnel visiting the base on an as-needed basis; the former military facility remains in use as a forward operating location, used by the military. This use came under scrutiny by the Base Realignment and Closure Committee in the late 2000s and was closed October 1, 2010; the Air Force retains responsibility for toxin cleanup in the area and engineers from Eielson Air Force Base in Fairbanks still visit the site on occasion.
The base is now controlled by the City of Galena, the Galena School District and the Alaska Department of Transportation. The Alaska Wing of the Civil Air Patrol was pursuing retaining one of the F-16 fighter hangars as a CAP facility for the CAP Wing in Galena, the "Yukon Squadron"; the City of Galena gained notoriety in 2011 when it was noted in media reports as being the US community which received the most benefits from lobbying efforts. The town evaded bankruptcy by aggressively lobbying for state and federal funds for the GILA boarding school in the town, which produced funds that turned the city's finances around. In May 2013, Galena suffered a freak catastrophic flood when the spring breakup on the Yukon River caused an ice jam 20 miles downstream, backing up the river and affecting 90% of homes in the city; this flood was on the scale of a flood never seen before by Galena residents. In the part of town closest to the river, houses were submerged to the roofs in water, properties on higher ground suffered damage also.
Most of the residents had to evacuate in thanks to the efforts of the local airline, volunteer missionary pilots, the Alaska National Guard. Some of the residents chose to stay behind and took refuge in the few last remaining dry parts of town; the flood dike the Air Force built around the runway managed to keep the river from inundating the runway and GILA. Efforts are underway to help Galena rebuild, with the assistance of the Federal Emergency Management Agency and volunteer groups. Galena is located at 64°44′26″N 156°53′8″W. Galena is located on the north bank of the Yukon River, 45 mi east of Nulato; the Innoko National Wildlife Refuge is southwest of Galena. According to the United States Census Bureau, the city has a total area of 24.0 square miles, of which, 17.9 square miles of it is land and 6.1 square miles of it is water. Galena is inaccessible by road to other parts of Alaska. Residents rely on river cargo in the brief summer season for the bulk of its needs, by air travel to access the outside world.
Galena first appeared on the 1890 U. S. Census as the unincorporated native village of "Notaloten", it would not appear again until 1930. It formally incorporated as a city in 1971; as of the census of 2010, there were 470 people, 190 households, 123 families residing in the city. The population density was 26.3 people per square mile. There were 264 housing units at an average density of 14.7 per square mile. The racial makeup of the city was 29.4% White, 0.0% Black or African American, 63.6% Native American, 0.6% Asian, 0.0% Pacific Islander, 0.20% from other races, 6.2% from two or more races. 2.3% of the population were Hispanic or Latino of any race. In the city, the age distribution of the population shows 29.3% under the age of 18, 11.0% from 20 to 29, 20.8% from 30 to 44, 27.6% from 45 to 64, 10.4% who were 65 years of age or older. The median age was 36.8 years. There were 229 females, 166 of whom were 18 years and over, 241 males, 171 of whom were 18 years and over; the median income for a household in the city was $60,313, the median income for a family was $62,917.
The per capita income for the city was $26,551. About 11.5% of the population were below the poverty line and 18.9% were below 125 percent of the poverty line. The headquarters for the Koyukuk/Innoko/Nowitna National Wildlife Refuge is located in Galena; the City of Galena is incorporated as a first-class city, governed by a city council. The city's mayor is Jon Korta; the Louden Tribal Counc
Construction of the Trans-Alaska Pipeline System
The construction of the Trans-Alaska Pipeline System included over 800 miles of oil pipeline, 12 pump stations, a new tanker port. Built on permafrost during 1975–77 between Prudhoe Bay and Valdez, the $8 billion effort required tens of thousands of people working in extreme temperatures and conditions; the first section of pipe was laid in 1975 after more than five years of legal and political arguments. Allegations of faulty welds drew intense scrutiny from national observers. A culture grew around the unique working conditions involved in constructing the pipeline, each union that worked on the project had a different function and stereotype. Thirty-two Alyeska Pipeline Service Company employees and contract workers were killed during the project; the main construction effort lasted until 1977. Several more pump stations, added as oil flow increased, were completed through 1980. Intensive geological sampling and survey work of the pipeline route started in spring 1970. Aerial photograph were taken, a preliminary route was detailed.
Small survey parties physically hammered stakes into the ground. The work was difficult. In places, the foliage was so dense that trees had to be cut down and progress was limited to 20,000 feet per day; the surveyed route passed through several mountain passes: Atigun Pass, Isabel Pass, Thompson Pass, Keystone Canyon. In the latter location, surveyors had to rappel down cliffs in order to perform their work. Surveyors and planners had to deal with the Denali Fault, a major cause of earthquakes, with large amounts of permafrost. In 1969, the unincorporated Trans-Alaska Pipeline System group drilled a series of core samples north of the Brooks Range that demonstrated how ubiquitous the permafrost was along the route; this forced the design of an elevated pipeline, tested in a 1,000 feet loop built near Barrow. This elevation required the pipeline to be insulated, since extreme cold temperatures caused the metal to become brittle when hot oil was being pumped through the pipeline. After ecological objections forced subterranean pipeline crossings, engineers developed a system by which the ground near the pipeline would be refrigerated by chilled brine.
These refrigerated sections would be placed in Styrofoam-lined trenches and covered with gravel for their insulation value. Altogether, 3.5 miles of the pipeline was designed to be built underground in this way. In other places, a lack of permafrost meant it could be placed underground without a special refrigeration plant. Large amounts of gravel were needed for all sections of the pipeline as insulation to keep the heat of above-ground structures from melting the permafrost. Gravel was needed to build the construction and maintenance road, surveyors located 470 sites across Alaska where the needed 65,000,000 cubic yards of gravel could be located; the Pipeline Authorization Act required the pipeline to be able to withstand the maximum earthquake recorded in the area it was built. When crossing the Denali Fault, Teflon-coated sliders were designed to allow the pipeline to move side-to-side in an earthquake. To protect against forward-and-backward shocks and to allow for thermal expansion, the pipeline wasn't designed as a straight line.
Instead, it was intended to be laid in an S-shape, the bends would allow for expansion and movement without breaking. Because most of the pipeline was built above permafrost, each of the pipes holding up the raised sections of pipeline contained a sealed tube of ammonia; as the permafrost below the pipeline warms, the ammonia absorbs the heat and rises to a radiator on top of each stanchion. The ammonia is cooled by the outside air and falls back to the bottom of the tube, where the process repeats; the surveyed route crossed hundreds of rivers. To cross these with the pipeline, engineers designed concrete "jackets" to surround the pipe and weight it down so it would sink to the bottom of the stream or river; because oil is lighter than water, the pipeline would float without the concrete jackets. Dredging rivers and burying the pipeline in the streambed was not allowed due to environmental concerns. In several places—either out of fear of disturbing the river or because of the river's characteristics—pipeline bridges were constructed.
The most notable of these are over the Tanana River. To protect against corrosion in these wet environments, the pipeline was designed with cathodic protection. In terms of spill prevention, the pipeline was designed with one-way valves, computer-aided leak detection, other features; the pipeline was designed to be pressurized, so any leak would be detected by a loss of pressure at one of the pump stations, which could sound an alarm and halt the flow of oil quickly. When it was proposed, the pipeline was scheduled to start at a capacity of 0.6 million barrels per day, with capacity to be expanded to 1.2 million barrels per day in two years, to 2 million barrels per day at an indeterminate time. The oil embargo scrapped these plans, it was intended that the pipeline be built with an initial capacity of 1.2 million barrels per day. This required eight pumping stations to be ready at startup increasing the manpower require