Introduction
The Great Salt Lake in northern Utah is the largest saltwater lake in the Western Hemisphere and the eighth-largest terminal lake in the world. At its average historical extent, the lake covers approximately 4,400 square kilometers, though its size fluctuates dramatically with climate and water usage. The lake is a remnant of the much larger prehistoric Lake Bonneville, which covered much of western Utah during the last Ice Age.
The Great Salt Lake has been shrinking at an alarming rate in recent decades, losing roughly half its surface area since 1987. This decline, driven by agricultural water diversions, urban growth, and drought exacerbated by climate change, poses a severe ecological and public health threat. If the lake continues to shrink, toxic dust laden with heavy metals from the exposed lakebed could affect the health of millions of people in the Salt Lake City metropolitan area.
Geography & Formation
- Surface Area: ~4,400 km² (historical average, now much smaller)
- Max Depth: ~10 m
- Elevation: ~1,280 m above sea level
- Salinity: 5-27% (varies by location and water level)
The Great Salt Lake occupies the lowest portion of the Great Basin, a vast region of internal drainage in the western United States where rivers have no outlet to the ocean. The lake is fed by the Bear, Weber, and Jordan Rivers, and like all terminal lakes, it loses water only through evaporation. This concentrates dissolved minerals, giving the lake its high salinity, which varies from about 5 percent on the fresher southeastern arm to 27 percent on the northern arm.
The lake is a remnant of Lake Bonneville, a freshwater lake that covered 51,000 square kilometers during the Pleistocene. Ancient shorelines etched into the mountains surrounding Salt Lake City are visible evidence of Bonneville's former extent. When the lake overflowed about 14,500 years ago, it carved Red Rock Pass in Idaho and catastrophically flooded down the Snake and Columbia Rivers to the Pacific Ocean.
Water & Hydrology
- Major Tributaries: Bear, Weber, Jordan Rivers
- Water Loss: Entirely through evaporation
- Water Consumption: 60-80% of inflow diverted before reaching lake
- Historic Low: 2022 (record low water level)
The Great Salt Lake's water crisis is fundamentally one of supply and demand. An estimated 60 to 80 percent of the water that would naturally flow into the lake is now diverted for agricultural irrigation and municipal use before it reaches the lake. The Bear River alone, the lake's largest tributary, has over 750 water rights claimed against it. Combined with declining snowpack in the Wasatch Mountains due to climate change, these diversions have pushed the lake to crisis levels.
In 2022, the Great Salt Lake reached its lowest recorded level, exposing hundreds of square kilometers of lakebed. The exposed sediments contain elevated concentrations of arsenic, mercury, and other heavy metals deposited over millennia. When these sediments dry and become airborne as dust, they pose a significant health risk to the 2.5 million people living along the Wasatch Front, drawing comparisons to the ecological disaster of the Aral Sea.
Ecology & Biodiversity
- Brine Shrimp: Trillions (supporting a $57 million industry)
- Migratory Birds: 5-10 million annually
- Key Bird Species: Wilson's phalaropes, eared grebes, American avocets
Despite its harsh salinity, the Great Salt Lake supports a remarkably productive ecosystem based on brine shrimp (Artemia franciscana) and brine flies. Trillions of brine shrimp inhabit the lake, forming the foundation of a food web that supports between 5 and 10 million migratory birds each year. The lake is the most important staging area for Wilson's phalaropes in the Western Hemisphere, with 500,000 birds stopping to feed on their migration from the northern United States to South America.
The brine shrimp also support a significant commercial harvest, producing cysts (eggs) worth approximately $57 million annually that are used worldwide as feed in aquaculture. As the lake shrinks and salinity increases, the brine shrimp population is threatened — above about 17 percent salinity, brine shrimp reproduction declines, and above 27 percent it ceases entirely. The collapse of the brine shrimp population would devastate both the commercial harvest and the millions of migratory birds that depend on them.
Cultural Significance
- Major City: Salt Lake City (1.2 million metro)
- Historic Event: Mormon settlement (1847)
- Art Installation: Spiral Jetty by Robert Smithson (1970)
The Great Salt Lake played a central role in the settlement of Utah. When Brigham Young and the Mormon pioneers arrived in the Salt Lake Valley in 1847, the lake dominated the landscape. The early settlers recognized both the lake's limitations (too salty for irrigation or drinking) and its resources (salt and mineral extraction). The city that grew on its shores became one of the most important in the American West.
Robert Smithson's Spiral Jetty, a 460-meter coil of black basalt rock and earth jutting into the northern arm of the lake, is one of the most famous examples of land art in the world. Created in 1970 when water levels were low, the artwork has been periodically submerged and revealed as the lake has fluctuated. The Spiral Jetty has become an unexpected symbol of the lake's environmental crisis, as its increasing visibility reflects the lake's declining water levels.
Visitor Experience
- Best Season: May to October
- Key Destinations: Antelope Island, Spiral Jetty, Great Salt Lake Marina
- Activities: Floating, birdwatching, hiking, photography
Antelope Island State Park, connected to the mainland by a causeway, is the most popular destination on the Great Salt Lake. The island supports a herd of free-roaming bison, pronghorn antelope, and mule deer, and its beaches allow visitors to experience floating in the salty water. The island's trails offer panoramic views of the lake and the Wasatch Mountains, and it is an excellent location for birdwatching during migration seasons.
Visiting the Spiral Jetty on the remote northern shore requires a long drive on unpaved roads but rewards with a surreal landscape of salt flats, pink-tinged water, and the iconic earthwork sculpture. The experience of floating in the Great Salt Lake is unique in North America — the high salinity makes it impossible to sink, though the water can sting eyes and any cuts. After floating, visitors are advised to rinse off promptly as the brine dries into an uncomfortable salt crust.
Key Facts
- The Great Salt Lake is the largest saltwater lake in the Western Hemisphere
- The lake has lost roughly half its surface area since 1987
- Between 5 and 10 million migratory birds depend on the lake annually
- The brine shrimp industry is worth $57 million per year
- Exposed lakebed sediments contain toxic heavy metals that can become airborne dust
Fun Facts
- The Great Salt Lake is a remnant of Lake Bonneville, which was over 10 times larger and as deep as 300 meters
- The lake is so salty in some areas that it rivals the Dead Sea
- Robert Smithson's Spiral Jetty land art was submerged for decades before reappearing as water levels dropped
- The Union Pacific Railroad built a causeway across the lake in 1959 that divides it into two arms with very different salinities
Final Thoughts
The Great Salt Lake is facing an existential crisis that mirrors the Aral Sea disaster. Once a vast inland sea supporting millions of migratory birds and a thriving commercial shrimp harvest, the lake has been reduced by reckless water consumption to a fraction of its former size. Saving the Great Salt Lake will require fundamental changes to water allocation in Utah, but the alternative — toxic dust storms, ecological collapse, and economic losses — is far worse than the cost of action.