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Great Salt Lake

2007 Schools Wikipedia Selection. Related subjects: General Geography

   Great Salt Lake, Utah
   Great Salt Lake, Utah - Satellite Photo of the Great Salt Lake as it
   looked in the summer of 2003 after five years of drought, reaching
   near-record lows.

    Satellite Photo of the Great Salt Lake as it looked in the summer of
        2003 after five years of drought, reaching near-record lows.

   Coordinates 41°0′N 112°0′W
   Lake type Endorheic
   hypersaline
   Primary sources Bear
   Jordan
   Weber
   Catchment area 21,500 square miles (34,601 km²)
   Basin countries USA
   Max-length 75 miles (120 km)
   Max-width 28 miles (45 km)
   Surface area ~1,700 square miles (~4,400 km²)
   Average depth 14 feet (4.3 m)
   Max-depth 33 feet (10 m) average, high of 45 feet in 1987, low of 24
   feet in 1963
   Surface elevation historical average of 4,200 feet (1,283 m), 4,196.6
   feet (1,279 m) as of 2006 August 24
   Islands 8-15 (variable, see Islands)
   Settlements Salt Lake and Ogden metropolitan areas.

   Great Salt Lake, located in the northern part of the U.S. state of
   Utah, is the largest salt lake in the Western Hemisphere, the fourth
   largest terminal lake in the world, and the 33rd largest lake on Earth.
   In an average year the lake covers an area of around 1,700 square miles
   (4,400 km²), but the lake's size fluctuates substantially due to its
   shallowness. For instance, in 1963 it reached its lowest recorded level
   at 950 square miles (1,529 km²), but in 1987 the surface area was at
   the historic high of 3,300 square miles(5,311 km²).

   The lake is the largest remnant of Lake Bonneville, a pluvial lake
   which covered much of western Utah in prehistoric times. Great Salt
   Lake is endorheic (has no outlet besides evaporation), and thus has
   very high salinity, far saltier than sea water. The Jordan, Weber, and
   Bear rivers (the three major tributaries) deposit around 1.1 million
   tons of minerals in the lake each year, and the balance of evaporated
   water is mineral-free, concentrating the lake further. Because of its
   unusually high salt concentration, most people can easily float in the
   lake as a result of the higher density of the water, particularly in
   the saltier north arm of the lake, Gunnison Bay. The lake's shallow,
   warm waters cause frequent, sometimes heavy lake-effect snows during
   late fall, early winter, and spring.

   Although it has been called "America's Dead Sea", the lake provides
   habitat for millions of shorebirds and waterfowl, including the largest
   staging population of Wilson's Phalarope in the world. In addition to
   native birds and brine shrimp, the lake is also home, oddly enough, to
   a Chilean flamingo named Pink Floyd.

Origin

   Great Salt Lake is a remnant of a much larger prehistoric lake called
   Lake Bonneville which, at its peak surface area, was nearly as large as
   Lake Michigan and significantly deeper, covering roughly ten times the
   area of Great Salt Lake and over 1,000 feet (305 m) deep. It covered
   much of present-day Utah and small portions of Idaho and Nevada during
   the Pleistocene Epoch, more commonly known as the Great Ice Age,
   between 32,000 and 14,000 years ago. With the change in climate, the
   lake began drying up, leaving Great Salt Lake, Utah Lake, Sevier Lake,
   Rush Lake, and Little Salt Lake as remnants.

Geography

   Great Salt Lake from airspace over Salt Lake City
   Enlarge
   Great Salt Lake from airspace over Salt Lake City

   Great Salt Lake lends its name to Salt Lake City, originally named
   "Great Salt Lake City" by then- President of The Church of Jesus Christ
   of Latter-day Saints (also known as the Mormon or LDS Church) Brigham
   Young, who led a group of Mormon Pioneers to the Salt Lake Valley
   southeast of the lake on 1847 July 24.

   Salt Lake City and its suburbs are located to the southeast and east of
   the lake, between the lake and the Wasatch Mountains, but land around
   the north and west shores is almost uninhabited. The Bonneville Salt
   Flats lie to the west, and the Oquirrh and Stansbury Mountains rise to
   the south.

   The Great Salt Lake is fed by three major rivers and several minor
   streams. The three major rivers are each fed directly or indirectly
   from the Uinta Mountain range in northeastern Utah. The Bear River
   starts on the north slope of the Uintas and flows north past Bear Lake,
   into which some of Bear River's waters have been diverted via a
   man-made canal into the lake, but later empty back into the river by
   means of the Bear Lake Outlet. The river then turns south in southern
   Idaho and eventually flows into the northeast arm of the Great Salt
   Lake. The Weber River also starts on the north slope of the Uinta
   Mountains and flows into the east edge of the lake. The Jordan River
   does not receive its water directly from the Uintas, rather it flows
   from freshwater Utah Lake, which itself is fed primarily by the Provo
   River; the Provo River does originate in the Uintas, a few miles from
   the Weber and Bear. The Jordan flows from the north part of Utah Lake
   into the southeast corner of the Great Salt Lake.

   A railroad line—the Lucin Cutoff—runs across the lake, crossing the
   southern end of Promontory Peninsula. The mostly-solid causeway
   supporting the railway divides the lake into three portions: the
   northeast arm, northwest arm, and southern. This causeway prevents the
   normal mixing of the waters of the lake due to its lack of water
   passages, and since there are no rivers, with the exception of a few
   minor streams, flowing directly into the northwest arm, Gunnison Bay,
   it is now substantially saltier than the rest of the lake.

Islands

   Categorically stating the number of islands is difficult, as the method
   used to determine what is an island is not necessarily the same in each
   source, and what may be considered an island in a high water year may
   be considered a peninsula in another. According to the U.S. Dept of the
   Interior / U.S. Geological Survey, "there are eight named islands in
   the lake that have never been totally submerged during historic time.
   All have been connected to the mainland by exposed shoals during
   periods of low water." In addition to these eight islands, the lake
   also contains a number of small islands, rocks, or shoals which become
   fully or partially submerged at high water levels.

   The Utah Geological Survey, on the other hand, states "the lake
   contains 11 recognized islands, although this number varies depending
   on the level of the lake. Seven islands are in the southern portion of
   the lake and four in the northwestern portion."

   The size and whether or not they are counted as islands depends mostly
   on the level of the lake, which can vary greatly from year to year.
   From largest to smallest, they are Antelope, Stansbury, Fremont,
   Carrington, Dolphin, Cub, Badger, Strongs Knob, Gunnison, Goose,
   Browns, Hat (Bird), Egg Island, Black Rock and White Rock. Dolphin,
   Gunnison, Cub, and Strongs Knob are in the northwest arm, and the rest
   are in the southern portion. There are also a number of small, unnamed
   islands.
   The Great Salt Lake as seen looking north towards Antelope Island from
   Sunset Beach
   Enlarge
   The Great Salt Lake as seen looking north towards Antelope Island from
   Sunset Beach

   Black Rock, Antelope Island, White Rock, Egg Island, Fremont Island,
   and the Promontory mountain range are each extensions of the Oquirrh
   Mountain Range, which dips beneath the lake at its southeastern shore.
   Stansbury, Carrington, and Hat Islands are extensions of the Stansbury
   mountain range, and Strongs Knob is an extension of the Lakeside
   Mountains which run along the lake's western shore. The lake is deepest
   in the area between these island chains, measured by Howard Stansbury
   in 1850 at about 35 feet (10.7 m) deep, and an average depth of 13 feet
   (4 m). When the water levels are low, Antelope Island becomes connected
   to the shore as a peninsula, as do Goose, Browns and some of the other
   islands. Stansbury Island and Strongs Knob remain peninsulas unless the
   water level rises above average. At high levels, some of the smaller
   islands become completely submerged.

Lake-effect

   Due to the warm waters of the Great Salt Lake, lake-effect snow is a
   frequent phenomena of the lake. Cold north, northwest, or west winds
   generally blow across the lake following the passage of a cold front,
   and the temperature difference between the warm lake and the cool air
   can form clouds that lead to precipitation downwind of the lake. It is
   typically heaviest from eastern Tooele County east and north into
   central Davis County. It can deposit highly localized but excessive
   snowfall amounts, generally with a narrow band of snow highly dependent
   on the direction the wind is blowing.

   The lake-effect snows are more likely to occur in late fall, early
   winter, and during spring due to the higher temperature differences
   between the lake and the air above it. The water is generally too cold
   to support lake-effect snow during mid-winter, since the lake
   temperatures usually fall to near the freezing point. During summer,
   the temperature differences can form thunderstorms that form over the
   lake and drift eastward along the northern Wasatch Front. Some
   rainstorms may also be partially contributed due to the lake-effect in
   fall and spring. It is estimated that approximately 6-8 lake-effect
   snowstorms occur in a year, and that 10% of the average precipitation
   of Salt Lake City can be attributed to the lake-effect.

Hydrology

   Map of Great Salt Lake
   Enlarge
   Map of Great Salt Lake

   Water levels have been recorded since 1875, averaging about 4,200 feet
   (1,280 m) above sea level. Since the Great Salt Lake is a shallow lake
   with gently sloping shores around all edges except on the south side,
   small variations in the water level can greatly affect the extent of
   the shoreline. The water level can rise dramatically in wet years and
   fall during drought years. The water level is also affected by the
   amount of water flow diverted for agricultural and urban uses. The
   Jordan and Weber rivers are particularly diverted for other uses. In
   the 1880s Grove Karl Gilbert predicted that the lake — then in the
   middle of many years of recession — would virtually disappear except
   for a small remnant between the islands.

   Great Salt Lake differs in elevation between the south and north parts.
   The Union Pacific Railroad causeway divides the lake into two parts.
   The water-surface elevation of the south part of the lake is usually
   0.5 to 2 feet higher than that of the north part because most of the
   inflow to the lake is to the south part.

West Desert Pumping Project

   Record high water levels in the 1980s caused massive property damage
   for owners on the eastern side of the lake, and started to erode the
   base of Interstate 80. In response, the State of Utah built the West
   Desert pumping project on the western side of the lake, featuring a
   pumping station at Hogup Ridge, containing three pumps with a combined
   capability of releasing 1.5 million gallons-per-minute; a 4.1 mile
   outlet canal, an inlet canal, which allowed water from the Newfoundland
   Evaporation Basin to return to Great Salt Lake; 25 miles of dikes, and
   a 10-mile access road between the railroad town of Lakeside and the
   pumping station.

   The project was designed to increase the surface area of the Great Salt
   Lake, and therefore the rate of evaporation. The pumps released Great
   Salt Lake's waters into the 320,000 acre (1300 km²) Newfoundland
   Evaporation Basin in the west desert. A weir in the dike at the south
   end of the Newfoundland Mountains regulated the level of water in the
   basin, and returned salty water from the basin to the main body of
   Great Salt Lake.

   At the end of their first year in operation, the pumps had released
   around 500,000 acre feet (0.6 km³) of water. The project was shut down
   in June of 1989, as the lake had dropped almost 6 feet (2 m) since
   reaching its peak in June 1986 and March 1987. The Utah Division of
   Water Resources credits the project with "over one-third of that
   decline." In total, the pumps released 2.73 million acre feet (3.4 km³)
   of water while they operated. Although the pumps are not currently in
   use, they are maintained in the event the lake rises to those levels
   again.

Salinity

   Most of the salts dissolved in the lake and deposited in the desert
   flats around it reflect the concentration of solutes by evaporation;
   Lake Bonneville itself was fresh enough to support populations of fish.
   More salt is added yearly via rivers and streams, though the amount is
   much less than the relict salt from Bonneville.

   The salinity of Great Salt Lake is highly variable, and depends on the
   lake's level; it ranges from 5 to 27% (or 50-270 ppt). The ionic
   composition is similar to seawater, much more so than the Dead Sea's;
   compared to the ocean, Great Salt Lake's waters are slightly enriched
   in potassium, and depleted in calcium.

Ecosystem

   The high salinity of the lake makes it uninhabitable for all but a few
   species, including brine shrimp, brine flies, and several forms of
   algae. The brine flies have an estimated population of over one hundred
   billion, and serve as the main source of food for many of the birds
   which migrate to the lake. However, the fresh- and salt-water wetlands
   along the eastern and northern edges of the Great Salt Lake provide
   critical habitat for millions of migratory shorebirds and waterfowl in
   western North America. These marshes account for approximately 75% of
   the wetlands in Utah. Some of the birds that depend on these marshes
   include: Wilson's phalarope, red-necked phalarope, American avocet,
   black-necked stilt, marbled godwit, snowy plover, western sandpiper,
   long-billed dowitcher, tundra swan, American white pelican, white-faced
   ibis, California gull, eared grebe, peregrine falcon, bald eagle, plus
   large populations of various ducks and geese.
   American avocets at Bear River Migratory Bird Refuge
   Enlarge
   American avocets at Bear River Migratory Bird Refuge

   There are twenty-seven private duck clubs, seven state waterfowl
   management areas, and a large federal bird refuge on Great Salt Lake's
   shores. Wetland/wildlife management areas include the Bear River
   Migratory Bird Refuge; Gillmor Sanctuary; Great Salt Lake Shorelands
   Preserve; Salt Creek, Public Shooting Grounds, Harold Crane, Locomotive
   Springs, Ogden Bay, Timpie Springs and Farmington Bay Waterfowl
   Management Areas.

   Several small islands in the lake provide critical nesting areas for
   various birds. Access to Hat, Gunnison and Cub islands is strictly
   limited by the State of Utah in an effort to protect nesting colonies
   of American white pelican (Pelecanus erythrorhynchos).

   There are no fish in the Great Salt Lake because of the high salinity.
   The only aquatic animals able to live in the lake are tiny brine shrimp
   (Artemia franciscana). Their tiny, hard-walled eggs or cysts (diameter
   of about 200 micrometers) are harvested in quantity during the fall and
   early winter. They are fed to prawns in Asia, sold as novelty "
   Sea-Monkeys," and used in testing of toxins, drugs, and other
   chemicals. There are also two species of salt flies and some bacteria
   and algae.

   Salinity differences between the sections of the lake separated by the
   railroad causeway result in significantly different biota. A
   phytoplankton community dominated by blue-green or green algae tint the
   water south of the causeway a greenish colour. North of the causeway,
   the lake is dominated by Dunaliella salina, a species of algae which
   releases beta-carotene, and halophilic bacteria which together give the
   water an unusual reddish or purplish colour. These colour differences
   are especially noticeable in satellite photographs. Although brine
   shrimp can be found in the arm of the lake north of the causeway,
   studies conducted by the Utah Division of Wildlife Resources indicate
   that these are likely transient. Populations of brine shrimp are mostly
   restricted to the lake's south arm.

Pink Floyd the flamingo

   As of 2005, a solitary Chilean flamingo named Pink Floyd winters at the
   Great Salt Lake. It escaped from Salt Lake City's Tracy Aviary in 1987
   and now lives in the wild, eating brine shrimp and socializing with
   gulls and swans. Utah residents have suggested petitioning the state to
   release more flamingos in an effort to keep Floyd company and as a
   possible tourist attraction. Wildlife biologists have resisted these
   efforts, saying that deliberate introduction of a non-native species
   would be ecologically unsound and might have detrimental consequences.

Elevated mercury levels

   U.S. Geological Survey and U.S. Fish & Wildlife researchers, originally
   studying selenium levels in the lake, discovered some of the highest
   levels of methyl-mercury they have ever seen, at 25 nanograms per liter
   of water. For comparison, a fish consumption advisory was issued at the
   Florida Everglades after water there was found to contain 1 nanogram
   per liter.

   This prompted further studies and a health advisory warning hunters not
   to eat Common Goldeneye or Northern Shoveler, two species of duck found
   in the lake. It has been stated that this does not pose a risk to other
   recreational users of the lake.

   After later studies were conducted with a larger number of birds, the
   advisories were revised and another was added for cinnamon teal. Seven
   other species of duck were studied and found to have levels of mercury
   below EPA guidelines, thus being determined safe to eat.

Commerce

   Solar evaporation ponds at Great Salt Lake's northeast end.
   Enlarge
   Solar evaporation ponds at Great Salt Lake's northeast end.

   The lake's north arm contains deposits of oil, but it is of poor
   quality and not economically feasible to extract and purify. As of
   1993, around 3,000 barrels of crude oil had been produced from shallow
   wells along the shore.

   Solar evaporation ponds at the edges of the lake produce salts and
   brine (water with high salt quantity). Minerals extracted from the lake
   include: sodium chloride (common salt), used in water softeners, salt
   lick blocks for livestock, and to melt ice on local roadways; potassium
   sulfate (potash), used as a commercial fertilizer; magnesium-chloride
   brine, used in the production of magnesium metal, chlorine gas, and as
   a dust suppressant. Food-grade salt is not produced from the lake, as
   it would require further costly processing to ensure its purity.
   Mineral-extraction companies operating on the lake pay royalties on
   their products to the State of Utah which owns the lake.

   The harvest of brine shrimp cysts during fall and early winter has
   developed into a significant local industry, with cysts selling for as
   high as $35 a pound. Brine shrimp were first harvested during the
   1950's and sold as commercial fish food. In the 1970's the focus
   changed to their eggs, known as cysts, which were sold primarily
   outside of the United States to be used as food for shrimp, prawns, and
   some fish. Today, these are mostly sold in the Orient and South
   America. The amount of cysts and the quality are affected by several
   factors, but salinity is most important. The cysts will hatch at 2 to
   3% salinity, but the greatest productivity is at salinities above about
   10%. If the salinity drops near 5 to 6%, the cysts will lose buoyancy
   and sink, making them more difficult to harvest.

   A large resort called Saltair has been operated on the southern shore
   of the lake. Rising and lowering water levels have affected Saltair,
   and it has burned down twice. The new resort built in 1981 after large
   fires completely destroyed the second and largest in the 1960s, is but
   a skeleton of the resort's former grandeur.

   Dramatically fluctuating lake levels have inhibited the creation and
   success of tourist-related developments. There is a problem with
   pollution of the lake by industrial and urban effluent. Also,
   especially when the waters are low, decay of insects and other wildlife
   give the shore of the lake a distinctive odour, which may keep some
   tourists from coming near the lake. Despite these issues, the lake
   remains one of Utah's largest tourist attractions. Antelope Island
   State Park is a popular tourist destination that offers panoramic views
   of the lake, hiking and biking trails, wildlife viewing and access to
   beaches.

Miscellanea

   The northwest arm of the lake, near Rozel Point, is the location for
   Robert Smithson's work of land art, Spiral Jetty (1970), which is only
   visible when the level of Great Salt Lake drops below 4,197.8 feet
   (1,280.2 m) above sea level.

   In mid-1877, J.H. McNeil was with many other Barnes and Co. Salt Works
   employees on the lake’s north shore in the evening. They claimed to
   have seen a large monster with a body like a crocodile and a horse’s
   head in the lake. They claimed this monster attacked the men, who
   quickly ran away and hid until morning. This creature is regarded by
   some to have simply been a buffalo in the lake. Thirty years prior,
   "Brother Bainbridge" claimed to have sighted a creature that looked
   like a dolphin in the lake near Antelope Island. This monster is called
   by some the "North Shore Monster."

   The lake and its shores contain oolitic sand, which are small, rounded,
   or spherical grains of sand made up of a nucleus (generally a fecal
   pellet or a small mineral grain) and concentric layers of calcium
   carbonate (lime) and look similar to very small pearls.

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