The Great Salt Lake is the largest saltwater lake in the Western Hemisphere and the eighth-largest terminal lake in the world. It lies in the northern part of the U.S. state of Utah and has a substantial impact upon the local climate, particularly through lake-effect snow. It is a remnant of Lake Bonneville, a prehistoric body of water that covered much of western Utah.
The United States Geological Survey has estimated that the historical average size of the lake (1847-1986) covers about . However, its area can fluctuate substantially due to its low average depth of . In the 1980s, it reached a historic high of , and the West Desert Pumping Project was established to mitigate flooding by pumping water from the lake into the Great Salt Lake Desert. In 2021, after years of sustained drought and increased water diversion upstream of the lake, it fell to its lowest recorded area at , falling below the previous low set in 1963.
The three major tributaries, the Jordan, Weber, and Bear rivers, together deposit around 1.1 million tons of minerals in the lake per year. Since the lake has no outlet besides evaporation, these minerals accumulate and give the lake high salinity (far saltier than seawater) and density. This density causes swimming in the lake to feel similar to floating.
The lake has been called "America's Dead Sea" and provides a habitat for millions of native birds, brine shrimp, nematodes, shorebirds, and waterfowl, including the largest staging population of Wilson's phalarope in the world.
Origin
The Great Salt Lake is a remnant of a much larger prehistoric lake called Lake Bonneville. At its greatest extent, Lake Bonneville spanned , nearly as large as present-day Lake Michigan and roughly ten times the area of the Great Salt Lake today. Bonneville reached at its deepest point and covered much of present-day Utah and small portions of Idaho and Nevada during the ice ages of the Pleistocene Epoch.
Lake Bonneville existed until about 16,800 years ago, when a large portion of the lake was released through the Red Rock Pass in Idaho, resulting in cataclysmic floods. With the warming climate, the remaining lake began to dry, leaving the Great Salt Lake, Utah Lake, Sevier Lake, and Rush Lake behind.
History
The Great Salt Lake entered written history through the records of Silvestre Vélez de Escalante, who learned of its existence from the Timpanogos Utes in 1776 during the Domínguez–Escalante expedition. No European name was given to it at the time, and it was not shown on the map by Bernardo Miera y Pacheco, the cartographer for the expedition. Escalante had been on the shores of Utah Lake, which he named Laguna Timpanogos. It was the larger of the two lakes that appeared on Miera's map. Other cartographers followed his lead and charted Lake Timpanogos as the largest (or larger) lake in the region. As people became aware of the Great Salt Lake, they interpreted the maps to think that "Timpanogos" referred to the Great Salt Lake. On some maps, the two names were used synonymously. In time, "Timpanogos" was dropped from the maps, and its original association with Utah Lake was forgotten.
In 1824, it was observed, apparently independently, by Jim Bridger and Etienne Provost. Shortly thereafter, other trappers saw it and walked around it. Most of the trappers, however, were illiterate and did not record their discoveries. As oral reports of their findings made their way to those who did make records, some errors were made. In 1843, John C. Fremont led the first scientific expedition to the lake, but with winter coming on, he did not take the time to survey the entire lake. Fremont's glowing reports of the area were published shortly after his expedition, and they influenced the choice of Brigham Young and other members of The Church of Jesus Christ of Latter-day Saints to settle in the Salt Lake Valley in July 1847. Young visited the lake three days after arriving in the valley, and it was supplying salt to the settlers within a month. The Great Salt Lake lends its name to Salt Lake City, originally named "Great Salt Lake City" by Young.
The lake was comprehensively surveyed for the first time in 1850 under the leadership of Howard Stansbury (Stansbury discovered and named the Stansbury mountain range and Stansbury island). Stansbury published a formal report of his survey work which became very popular. His report of the area included a discussion of Mormon religious practices based on Stansbury's interaction with the Mormon community in Great Salt Lake City.
Beginning in November 1895, artist and author Alfred Lambourne spent a year living on the remote Gunnison Island, where he wrote a book of musing and poetry, Our Inland Sea. From November 1895 to March 1896, he was alone. In March, a few guano sifters arrived to harvest and sell the guano of the nesting birds as fertilizer. Lambourne includes musings about these guano sifters in his work. Lambourne left the island early in the winter of 1896 along with the first group of guano sifters.
Causeway A causeway across the lake was built in the 1950s by the Morrison-Knudsen construction company for the Southern Pacific Railroad as a replacement to a previously built wooden trestle, which was the major component of the Lucin Cutoff. The route is owned and operated by Union Pacific. About 15 trains cross the causeway each day. Before 2016, the causeway constrained the flow of water between the northern and southern arms, which had a significant impact on various industries surrounding the lake. The construction of a bridge created an opening of the causeway for water to flow between the arms of the lake.
Willard Bay Reservoir Willard Bay, also known as Willard Bay Reservoir or Arthur V. Watkins Reservoir, is a freshwater reservoir completed in 1964, which separated, drained, and subsequently filled with fresh water from the Weber River a portion of the Great Salt Lake's northeastern arm.
West Desert Pumping Project Record high water levels in the 1980s caused a large amount of property damage for owners on the eastern side of the Great Salt Lake, and the water started to erode the base of Interstate 80. In response, the Utah government built the West Desert Pumping Project on the western side of the lake in 1987. This project consists of a pumping station () at Hogup Ridge, containing three pumps with a combined capacity of moving , an inlet canal, and an outlet canal. Also, there are of dikes and a access road between the town of Lakeside and the pumping station..
The pumping project was designed to increase the surface area of the Great Salt Lake and thus increase the rate of water evaporation. The pumps drove water into the Newfoundland Evaporation Basin in the desert west of the lake. A weir in the dike at the southern end of the Newfoundland Mountains regulated the level of water in the basin, and it sometimes returned salty water from the evaporation basin into the main body of the lake.
At the end of their first year of operation, the pumps had removed about of water from the Great Salt Lake. The project was shut down in June 1989, as the level of the lake had dropped by nearly since reaching its peak levels during 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 removed of water while they operated. Although the pumps are no longer in use, they have been kept in place in case the lake level rises that high again.
Shrinking
Drought conditions, climate change, and the overuse of snowmelt have caused the lake to shrink considerably. As of July 2022, the Great Salt Lake occupies approximately . In 1987, it occupied about . In modern times, the highest recorded surface elevation was on April 15, 1987, and the lowest recorded surface elevation was on December 17, 2022. In 2023, scientists at Brigham Young University estimated that without policy changes, the lake could dry up by 2028, with local species killed off by overly salty water somewhat before that. Continued shrinkage could also turn the lake into a bowl of toxic dust, poisoning the air around Salt Lake City.
Environmentalists proposed establishing a level of above sea level as an official state policy, among other interventions. University of Utah researchers proposed a level between 4,198 and 4,205 feet. A non-binding resolution in the 2023 state legislative session to adopt 4,198 feet was voted down, and Governor Spencer Cox called it "dumb" as there isn't any infrastructure in place to guarantee that donated or sub-leased water rights would actually make it to the lake.
Geography
The lake lies in parts of five counties: Box Elder, Davis, Tooele, Weber, and Salt Lake. 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 Great Salt Lake Desert and Bonneville Salt Flats are 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 flows into the northeast arm of the 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 is fed primarily by the Provo River. The Provo originates 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. The causeway obstructed the normal mixing of the waters of the lake, because there were only three wide breaches. Because no rivers, except a few minor streams, flow directly into the northwest arm, Gunnison Bay, it is substantially saltier than the rest of the lake. This saltier environment promotes different types of algae from those growing in the southern part of the lake, leading to a marked color difference on the two sides of the causeway. In December 2016, the opening of a bridge allowed water to flow from the southern arm of the lake into the northwest arm. At the time of opening of the causeway, the northwest arm was nearly lower than the southern arm. By April 2017, the levels of both arms of the lake had risen due to spring runoff, and the northwest arm was within of the southern arm.
Islands