The an excellent Salt Lake. This photo was take away by one astronaut board the International space Station in the summer the 2001. (Image credit: NASA planet Observatory)
Great Salt Lake, in northern Utah, is the biggest lake west that the Mississippi River and also the largest salt lake in the west Hemisphere. Sometimes referred to together America’s Dead Sea, the is however a critically essential habitat for millions of native and also migratory birds and also is a federally managed bird refuge. The is likewise home come several species of algae, brine shrimp and also brine flies.

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Great Salt Lake includes several islands, causeways, a railroad, 3 state parks and an earthwork sculpture called the Spiral Jetty. The lake is a famous recreation area, v hiking, sailing and swimming available.


Great Salt Lake is commonly bigger 보다 the claims of Delaware and also Rhode Island, follow to the U.S. Geological inspection (USGS). The size changes, however, as water levels rise and fall. The lake is just 14 feet (4 meters) deep on mean so a foot that water loss have the right to make a big difference in its complete size.

These space the mean dimensions of an excellent Salt Lake, according to USGS, girlfriend of great Salt Lake, and the university of Utah.

Surface area: 1,700 square mile (4,402 square kilometers) on an typical yearLength: 75 mile (120 km)Width: 28 miles (45 km)Average altitude the the water surface: 4,200 feet (1,280 meters)Maximum depth: 33 feet (10 m)Average depth: 14 feet (4 m)Total watershed area: 21,000 square miles (54389.75 square km), encompassing many of north Utah and also parts that Nevada, Idaho and also Wyoming.Record high water level: In 1986, the altitude in ~ the water surface was 4,212 feet (1,283 m) and the lake’s complete surface area was 2,300 square mile (5,956 square km).Record low water level: In 1963, the altitude in ~ the water surface was 4,191 feet (1,277 m) and also the lake’s total surface area was 937 square miles (2,426 square km).


Great Salt Lake lies in a region of the Western joined States dubbed the an excellent Basin. The Wasatch range rises to the east of the lake, with number of 11,000-foot mountains. The an excellent Salt Lake Desert is west the the lake. It features a flat expanse that salt crust called the Bonneville Salt Flats, which has ideal problems for attempts to break land-speed records.

The lake is a remnant of Lake Bonneville, one ancient, freshwater lake indigenous the last ice cream Age, claimed Bonnie Baxter, manager of the good Salt Lake Institute and a professor of biology in ~ Westminster college in Salt Lake City. Lake Bonneville was 325 miles (523 km) long and also 135 miles (217 km) large and 1,000 feet (308 m) deep.

Lake Bonneville formed about 30,000 years earlier from a small saline lake. Almost 17,000 years ago, Lake Bonneville overflowed at Red Rock happen in Idaho and a yearlong flood ensued. The lake lost about 375 feet (114 m) the water, according to the USGS. Lake Bonneville underwent several periods of shrinking and also stabilizing. These changes were due to increased evaporation and also a warming climate. There space four various shorelines visible together ridges top top Utah’s Wasatch Mountains. The Bonneville Salt Flats in western Utah room a remnant of Lake Bonneville.

The modern an excellent Salt Lake emerged around 10,000 year ago. Local aboriginal American people knew about an excellent Salt Lake, the course. The an initial non-native human being to watch the lake is stated to be explorer Jim Bridger in 1824, according to the Utah geological Survey. The very first thorough expedition of the lake to be by a party led by man C. Fremont in 1843. On that expedition, Kit Carson visited among the lake"s islands and carved a cross close to the summit of one island the is now referred to as Fremont Island. Members of the Church the Jesus Christ the Latter-day Saints (or Mormons) arrived in the area in 1847 and used the islands because that grazing cattle and likewise enjoyed swim in the lake and holding picnics ~ above its shores.

On may 10, 1869, the Transcontinental Railroad was completed ~ above the Promontory Peninsula on the north finish of good Salt Lake. Though momentous, this wedding the the rails was no efficient; great Salt Lake had actually caused the engineers to build a detour onto the rugged mountains of the peninsula. In 1902, the southern Pacific constructed an east-west wood railroad trestle across good Salt Lake dubbed the Lucien Cutoff, i beg your pardon bypassed Promontory Peninsula completely, follow to American Rails. In 1959 the wood trestle was replaced with a rock-fill causeway the is quiet in use today.


As Lake Bonneville shrank, every one of the minerals in it — including salt — focused into steadily much less water. Every year, 2.2 million loads (1,814, 369 metric tons) the salt operation into great Salt Lake indigenous tributary rivers, follow to USGS. “This buildup of minerals and no outlet to the s results in a salt lake,” said Baxter.

“Terminal lakes are frequently salty,” she said Live Science. “Water evaporates, however salt stays behind and accumulates. A terminal lake holds whatever that has actually ever entered the lake except water, which can leave by evaporation.”

Great Salt Lake is a salt chloride lake, stated Baxter. The hypersaline northern arm (also called Gunnison Bay) is around 30 percent salt. The southern portion of the lake (also called Gilbert Bay) fluctuates in between 6 and 27 percent salinity. Around 4.3 billion loads (3,628,738,960 metric tons) that salt are in great Salt Lake.

As with many other saline lakes, consisting of the Dead Sea, it is possible to to rise in great Salt Lake.


An aerial shot reflects the causeway the divides the northern and also southern parts of the an excellent Salt Lake. The rosy color of the northern waters is the result of the pigmented, salt-loving microbes. (Image credit: Courtesy of an excellent Salt Lake Institute)


Great Salt Lake has actually three feeders: the Bear, Weber and also Jordan rivers, follow to great Salt Lake info System at Utah State University. These rivers carry fresh water from melted snow in the Wasatch Mountains right into the eastern area of the lake. Sixty-six percent of fresh water start the lake originates from these rivers. Added fresh water comes from rainfall, groundwater and springs, according to good Salt Lake Ecosystem Program. No feeders reach Gunnison just in the northwestern part of the lake. The western part of the good Salt Lake watershed is desert and also does not bring water into the lake other than in very wet years.

There space 11 islands in great Salt Lake, consisting of the 28,800-acre (116 square km) Antelope Island, i m sorry is residence to a state park and one of America’s largest free-roaming herds the bison, according to the Utah State Parks. Gunnison Island is home to a big population that pelicans. Number of of the bigger islands in the southern part of an excellent Salt Lake, including Antelope Island, end up being peninsulas once the water level is low. The Promontory Peninsula, house to the golden Spike National historical Site, divides Gunnison bay from the remainder of the north area of the lake (also called Bear river Bay).

Willard only is a human-made freshwater reservoir ~ above the northeastern flood plains of great Salt Lake, according to Utah State Parks. The area to be separated from great Salt Lake in 1964 and is now a state park.

The Spiral Jetty is a massive earthwork sculpture top top the north shore of good Salt Lake. Earthwork artist Robert Smithson constructed it in 1970. Smithson used much more than 6,000 tons (5,443 metric tons) of black basalt rocks and earth dug up from the website to develop a 1,500-foot-long (457 m) spiral the extends into the water, according to Dia Art. The is visible as soon as the water level is below 4,197 feet (1,279 m) altitude.

The Union Pacific Railroad northern Causeway is 21 miles (33 km) long and also was constructed as a railroad shortcut. That divides Gunnison Bay, the north arm that the lake, indigenous Gilbert just in the south, follow to friends of good Salt Lake. Human-built attributes like causeways and dykes impede water flow, which create microenvironments, claimed Jaimi Butler, coordinator that the great Salt Lake Institute. The clearest example of this is in the much north of the lake, wherein the Union Pacific Railroad northern Causeway blocks freshwater flow and also has created a super-saturation the salt and an extreme environment.

“Not countless things live increase there, and the microbes that execute are pink or red,” claimed Butler. “Their red pigments aid them resolve the harsh environment.” together a result, the water is often pink colored.

Mineral extractionis a significant economic function of an excellent Salt Lake, said Butler. According to USGS, five businesses extract salt and other minerals from the lake with solar evaporation ponds. No food-grade salt originates from the lake; good Salt Lake salt is offered for deicers, road salt, water softeners and salt licks because that livestock. Additionally, claimed Butler, a enormous brine shrimp harvest occurs every fall. The brine shrimp are mainly sent come Asia and also South America where they are offered as feeders because that commercially get an impression prawn and fish.

Among Utah residents, an excellent Salt Lake is well known for periodically emitting a stench favor rotten eggs. It is caused by hydrogen sulfide, i m sorry certain varieties of bacteria in the lakebed breath out into the air. Despite the odor annoys humans, butler emphasized the it is simply “microbes doing your job. They room transforming energy into part other type that is beneficial to the birds and the bugs.”

Oolitic sand is pill-shaped sand widespread on the bottom of great Salt Lake and also several beaches. That is soft, smooth and round unlike consistent sand that is jagged-edged, follow to an excellent Salt Lake Ecosystem Program. A serial of oolitic sand starts as a brine shrimp fecal pellet or other tiny bit of debris. Calcium and magnesium lead carbonate particles develop up approximately it, developing oolitic sand and also separating brine shrimp waste from the rest of the water. In this way, oolitic sand functions as a filter for good Salt Lake.


Great Salt Lake has a vibrant and unique ecosystem. The is most famous as an essential refuge for moving birds. “Great Salt Lake is the largest inland human body of water on the Pacific flyway,” described Baxter. “This is a vital habitat for migrating birds come feed and grow in before they move on. Over there are only two invertebrates in the lake, brine shrimp and brine flies, however the number of these species provide an amazing amount the food for these birds.”

The dimension of its wetlands and the diversity of that aquatic environments additionally make an excellent Salt Lake appeal to numerous different bird species. Some room the American avocet, phalarope, fully eagle, barn owl, earn grebe, golden eagle, north harrier and also snowy plover, follow to an excellent Salt Lake Marina.

“We have actually one of America’s biggest pelican populations,” added Butler. “Pelicans eat fish but they colony in Gunnison Island, in the northern arm of the lake that has 10 times the amount of salt together the ocean. They nest there since it’s remote and also there space no predators top top the island.”

According to good Salt Lake Ecosystem Program, much more than 7.5 million bird in 257 types either avoid at great Salt Lake ~ above their migrations of live at it, consisting of one-third of the world’s populace of phalaropes (500,000 birds).

Brine shrimp space the most populous pet in good Salt Lake. These small crustaceans live in salt water roughly the world, however only one species, Artemia franciscana, lives in good Salt Lake. Castle measure as much as 0.5 inch (1.37 centimeters) long and also can live in water through up come 33 percent salinity, follow to an excellent Salt Lake Ecosystem Program. Lock can control how much salt gets into their human body tissues much better than any kind of other organism on Earth due to skin lining their stomachs and gills. Researchers suspect the they originally came to great Salt Lake together embryos in safety shells top top the feet of migrating birds.

There space at least three species of brine flies that flourish at good Salt Lake. Scientists estimate that there may be billions the brine paris swarming about the lake throughout the summer, according to an excellent Salt Lake Ecosystem Program. They room visible together swarms of small brown insects, yet they do not bite. In their larval state, theyeat birds blooms in the water.


There are many threats to good Salt Lake, stated Butler, however by much the many pressing is water loss. Due to the fact that 2011, great Salt Lake has shrunk by nearly 40 percent. In November 2016, NASA exit satellite pictures demonstrating the decline. Approximately 50 percent that the lake bed is now exposed.

The West is in a dryness cycle that, compounded by warming temperature in Utah and also surrounding states, outcomes in less snowpack and also precipitation, and, consequently less water entering an excellent Salt Lake v rivers, snowfall and also rainfall, stated Butler.

But regional human task plays a lot bigger function in good Salt Lake water loss. A 2016 white file co-authored through Wayne Wurtsbaugh and also published by the Utah State University defines how water flowing into the lake indigenous rivers has actually been lessened by 39 percent in the critical 150 years. Currently, about 40 percent of the river water is diverted and also used because that farming, industry and also other creates of human being consumption. Follow to Wurtsbaugh, human water use has lowered the lake level 11 feet (3.3 meters) in the critical 10 years.

Water ns affects the entire ecosystem of great Salt Lake. It increases salinity, which could impact brine shrimp and also birds. Migrating fowl have actually fewer areas to stay, together wetlands are desiccated. Butler listed the pelican population: “Pelicans colony on Gunnison Island due to the fact that it has no predators, however when the water levels are too low, predators have the right to walk out to the island.”

Additionally, stated Butler, water loss effects the salt and brine shrimp harvest economy. The devices aren’t built for low water levels. Reduced lake levels additionally increase wind-blown dust, make the lake less obtainable via boat and could have actually unforeseen results on the Utah climate.

Humans also influence the lake through pollution. Great Salt Lake is unique amongst saline lakes in the it is beside a significant metropolitan area, claimed Butler, and the Salt Lake City area is intended to double to 4 million civilization over the next 30 years. The proximity can cause problems, which room exacerbated by good Salt Lake’s lack of outlet. “Everything that happens in the watershed and airshed have the right to be watched in the lake,” stated Butler. Rivers lug not only trash but toxins and other chemicals into great Salt Lake. Polluted air bring in additional toxins.

But toxin troubles don’t only come from regional sources. According to the college of Utah hereditary Learning scientific research Center, good Salt Lake has the highest possible levels of mercury of anywhere in the united States. Industry roughly the people emits mercury toxins, yet they room benign in the atmosphere. Bacteria in good Salt Lake revolve it right into toxic mercury.

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Butler emphasized that the mercury exists primarily in a deep brine class (about 19 feet or 6 meter down), i m sorry the consistent water and also brine does not penetrate. Therefore, that is for sure for human beings to swim in an excellent Salt Lake. Advisories have actually been approve for people to avoid eating usual goldeneye, cinnamon teal and also northern shoveler duck captured around good Salt Lake since of your mercury levels.