How Much Has the Great Salt Lake Shrunk?

The Great Salt Lake has lost roughly half its water over the past several decades and hit its lowest recorded volume in 2022, capping a decline that has exposed hundreds of square miles of lakebed. Between 2000 and 2018 alone, the lake’s surface dropped about 1.7 meters and its footprint shrank by around 900 square kilometers. The causes, consequences, and possible fixes for this collapse are more tangled than a simple drought story, involving irrigated agriculture, a warming climate, toxic dust, and an ecosystem found nowhere else on Earth.

How the Numbers Have Changed Since Settlers First Measured the Lake

When Mormon pioneers reached the Salt Lake Valley in 1847, the lake was already a sprawling, shallow terminal lake with no outlet to the sea. By 1986, it had swelled to a historic high, covering about 2,300 square miles at an elevation of roughly 4,212 feet above sea level.¹ That high-water mark came after years of heavy snowpack in the surrounding mountains, and the lake flooded railroad causeways and pumping stations built on the assumption it would stay smaller. The swing between extremes has always been dramatic: the lake hit a previous historic low of about 4,191 feet in 1963 before rebounding to that 1986 peak, a range of more than 20 feet.

What happened after 1986 was different. Instead of oscillating, the lake entered a long, mostly one-directional decline. From 1989 to 2022, the surface dropped at an average rate of about 0.1 meter per year.² By the autumn of 2022, the lake reached the lowest water volume in its entire 170-plus-year measurement record.³ Satellite imagery shows the lake’s surface area shrank by about 901 square kilometers just between 2000 and 2018, a loss visible from space as pale, salt-crusted flats emerged where water once sat.⁴

To put the total human-era decline in perspective, researchers who reconstructed the lake’s water inputs from 1847 to 2023 estimated that upstream water consumption has driven a cumulative lake-level drop of as much as 4.6 meters, or about 15 feet.⁵ Because the lake is shallow and broad, even modest changes in depth translate into enormous changes in surface area and volume. A few feet of decline can uncover thousands of acres of lakebed.

What Is Draining the Lake

The popular explanation is drought, and drought does play a role, but it is not the main driver. The dominant cause is straightforward: people intercept nearly two-thirds of the river water and shallow groundwater that would otherwise flow into the lake.² Agriculture accounts for about 71 percent of those diversions, and within agriculture, the picture is strikingly narrow. Roughly 80 percent of agricultural water in the basin goes to growing cattle-feed crops, mainly alfalfa and grass hay, to support nearly a million head of cattle for dairy and beef production.² In other words, the lake’s fate is closely tied to the economics of livestock feed in the arid West.

Climate change compounds the problem. Rising temperatures mean less precipitation falls as snow, the snowpack that does form melts earlier, and more water evaporates from soils and from the lake surface itself. Research on terminal lakes across the Great Basin found that warming coincides with fewer days of snow cover, decreased inflow, and greater evaporation.⁶ Climate projections for the Great Salt Lake basin are sobering: modeling suggests that continued warming could reduce the snowpack’s water content by around 71 percent and cut runoff by roughly 20 percent.⁷ Meanwhile, the volume of water diverted upstream has not decreased to match the shrinking supply, pushing the lake’s water budget further into deficit.

Urban growth adds another layer. The Wasatch Front, the strip of cities running from Provo through Salt Lake City to Ogden, is one of the fastest-growing metro areas in the country. Per-person water use has dropped about 18 percent thanks to conservation, but because the population keeps climbing, overall municipal water use has still risen by roughly 5 percent.⁸ Municipal use is a smaller slice of the pie than agriculture, but it moves in the wrong direction and is politically harder to cut than farm water because it directly affects voters.

What the Lake Supports and What Happens When It Shrinks

The Great Salt Lake is sometimes dismissed as a dead, salty curiosity, but it anchors a surprisingly productive ecosystem. Brine shrimp and brine flies thrive in its briny water, forming the base of a food web that feeds millions of migratory birds. The lake is a hemispheric-scale stopover: Wilson’s phalaropes and red-necked phalaropes, among other species, depend on its shallow, brackish margins to refuel during migration. Large flocks prefer the shallower, less salty parts of the lake, and those are precisely the areas most vulnerable to further declines in freshwater inflow.⁹

Salinity is the key variable for the organisms that live in the water. As the lake shrinks, the same amount of dissolved salt is concentrated in less and less water, driving salinity up. Lab experiments show that brine shrimp survive best at moderate salt concentrations (around 90 parts per thousand) and decline sharply at both very low and very high levels.¹⁰ As salinity climbed past 225 parts per thousand in microcosm experiments, brine shrimp became nearly absent, and brine fly biomass dropped by about 45 percent across the upper salinity range.¹¹ Without those invertebrates, the birds that rely on them lose their food supply.

Below the waterline, ancient microbialites, reef-like structures built by microbial communities over thousands of years, are being exposed to air as the lake recedes.¹² Once exposed, these structures dry out and begin to crumble. Their outer surfaces lose their living microbial coating and turn sandy, then erode quickly when rain or wave action reaches them. Because microbialites are assumed to grow extremely slowly, the damage from even a few years of exposure could take centuries to reverse, if it can be reversed at all.¹³ These structures are not just geological curiosities; they contribute to nutrient cycling in the lake and support the base of the food web.

Toxic Dust From the Exposed Lakebed

When a terminal lake shrinks, it leaves behind a flat expanse of fine sediment laced with whatever the inflowing rivers carried in over millennia, including heavy metals. The Great Salt Lake’s newly exposed playa is a growing source of airborne dust that blows into the Wasatch Front, where roughly 2.5 million people live.

Analysis of that dust finds elevated concentrations of several metals classified as priority pollutants by the EPA. Zinc, copper, and lead showed the highest total concentrations, while cadmium, thallium, and selenium were among the most easily mobilized into soils and water. Simulated stomach-acid extractions showed that cadmium, lead, and arsenic were highly bioaccessible, meaning a child who swallows lakebed dust can absorb a meaningful amount of those metals. Arsenic was the primary driver of estimated non-cancer health risk from ingestion, and the risk was higher for children than for adults.¹⁴ Greenhouse experiments even showed uptake of arsenic and other metals in cabbage leaves exposed to the dust, raising questions about contamination of local food production.¹⁴

The respiratory effects are concerning, too. When mice were exposed to Great Salt Lake dust particles, the dust triggered inflammation in the lungs, including a surge in neutrophils and elevated levels of inflammatory signaling molecules.¹⁵ A separate evaluation of dust deposited in northern Utah communities concluded that children under six are especially vulnerable to health hazards from ingestion at higher rates. Among the metals contributing most to estimated hazard, arsenic and lead were likely derived from the lake’s playa emissions, suggesting that keeping the lakebed submerged is itself a public health measure.¹⁶

Comparisons to other dried-out lakes are hard to avoid. The Owens Lake disaster in California, where the dried lakebed became the single worst source of particulate air pollution in the United States, offers a cautionary parallel. The Great Salt Lake’s exposed area is already far larger than Owens Lake’s playa ever was, and the population downwind is much bigger.

Dust on Snow and the Water-Supply Feedback Loop

There is an underappreciated feedback loop in the lake’s decline. When dust from the exposed lakebed blows east, some of it lands on the Wasatch Range snowpack. Dark dust particles absorb sunlight that clean white snow would reflect, accelerating the melt. A case study of a single mid-April dust event found that dust from sources including the Great Salt Lake dry lakebed accounted for roughly half the season’s total dust loading on the snowpack and sped up snowmelt by about five days.¹⁷

Five days may not sound dramatic, but the timing of snowmelt matters enormously for water supply in the arid West. Earlier melt means more runoff arrives before the growing season, when reservoirs are already full and fields do not yet need irrigation. More water spills past the system unused, and less is available in late summer when demand peaks. So a shrinking lake produces more dust, which melts the snowpack faster, which reduces the water that reaches the lake, which exposes more lakebed, which produces more dust. The researchers noted that the northern Wasatch, closer to the lake, likely experiences even stronger dust deposition and faster melt acceleration than the modeling site they studied.

Can You Refill the Lake?

The most dramatic proposal floated in recent years is a pipeline from the Pacific Ocean to pump seawater into the Great Salt Lake. The idea has a certain brute-force appeal, but the engineering and energy requirements are staggering. Pumping ocean water over the mountains and across hundreds of miles of desert would require at least 400 megawatts of electricity during operation, equivalent to a large power plant or about 11 percent of Utah’s total annual electricity demand. At current energy prices, the electricity alone would cost over $300 million per year and emit nearly a million metric tons of carbon dioxide annually.¹⁸ Those figures are the optimistic baseline; with longer routes, mountainous terrain, larger volumes, or less-efficient pumps, the costs could easily triple. The proposal also raises questions about introducing ocean chemistry into a lake whose ecology evolved with a very different mineral profile.

The more realistic, if less exciting, set of solutions involves reducing the amount of freshwater diverted before it reaches the lake. Because agriculture dominates the water budget, any serious plan has to confront irrigation. Some options include converting from flood irrigation to more efficient sprinkler or drip systems, fallowing fields in dry years in exchange for payments, shifting away from water-intensive crops like alfalfa, or reducing the size of the cattle-feed sector. Utah’s legislature has taken incremental steps, including funding water trusts and creating frameworks for temporary water leasing, but the scale of change needed is much larger than what has been enacted so far.

The 2023 and 2024 water years brought above-average snowpack and a partial rebound in lake levels, providing a temporary reprieve. But one or two wet years do not reverse a structural deficit. The lake’s long-term trajectory depends on whether the region can permanently reduce upstream consumption by a large enough margin to offset both existing diversions and the additional losses from a warming climate.

Who Worries About the Lake, and What They Worry About

Public concern about the Great Salt Lake’s decline is not evenly distributed across the population. A survey of Salt Lake County residents found meaningful differences in what aspects of the crisis people care about, shaped by demographic and personal factors. Hispanic, Latino, and Pacific Islander residents expressed more concern than White residents about the loss of animal habitats and the region’s ability to sustain life, while foreign-born residents were more concerned than U.S.-born residents about quality-of-life impacts.¹⁹

These differences matter for policy. If outreach about the lake’s decline focuses only on ecological loss, it may resonate with some communities but miss the quality-of-life concerns, including air quality, property values, and economic disruption, that motivate others. Effective advocacy probably requires framing the issue in multiple ways rather than assuming everyone shares the same entry point. The survey also hints at a broader challenge: for many residents, the lake has long been treated as an afterthought, a smelly oddity on the way to the airport rather than a critical piece of regional infrastructure. Changing that perception is arguably as important as changing water policy, because public support is what makes politically difficult water reforms possible.

The Brine Shrimp Industry

One often-overlooked economic dimension is the Great Salt Lake’s commercial brine shrimp harvest, which supplies cysts (essentially eggs in a dormant state) to the global aquaculture industry. These cysts are used worldwide as a first food for farmed fish and shrimp larvae. Utah’s harvest has historically been worth tens of millions of dollars annually and supplies a large share of the global market. As salinity fluctuates with the lake’s volume, so does brine shrimp productivity. The relationship is not linear: too little salt and predatory fish can survive, eating the shrimp; too much salt and the shrimp themselves struggle to reproduce and grow. The salinity sweet spot is relatively narrow, and the lake has been pushed toward and occasionally past its upper threshold in recent low-water years. A collapse of the brine shrimp population would ripple through aquaculture supply chains well beyond Utah.

The mineral extraction industry is also directly tied to lake volume. Companies pump lake brine into solar evaporation ponds to harvest magnesium, potassium, and other salts. Lower lake levels mean the remaining brine becomes more concentrated, which can be temporarily useful for extraction efficiency but ultimately reduces the total volume available to pump. Some mineral operations hold senior water rights that effectively compete with the lake itself for the remaining water, creating a tension between short-term industrial value and long-term lake survival.

1
U.S. Geological Survey. Hydrologic characteristics of the Great Salt Lake, Utah: 1847-1986
2
Environmental Challenges. Reducing irrigation of livestock feed is essential to saving Great Salt Lake
3
Geophysical Research Letters. Explaining the 2022 Record Low Great Salt Lake Volume
4
Remote Sensing of Environment. The role of declining snow cover in the desiccation of the Great Salt Lake, Utah, using MODIS data
5
ESS Open Archive. Evaluating Variations in Great Salt Lake Inflow to Infer Human Consumptive Water Use, A Volume Reconstruction Approach
6
Earth and Space Science. Intensified Warming and Aridity Accelerate Terminal Lake Desiccation in the Great Basin of the Western United States
7
Water. Impacts of Changing Temperatures on the Water Budget in the Great Salt Lake Basin
8
DigitalCommons@USU. Impacts of Water Development on Great Salt Lake and the Wasatch Front
9
Ornithological Applications. Threatened habitat at Great Salt Lake: Importance of shallow-water and brackish habitats to Wilson’s and Red-necked phalaropes
10
Hydrobiologia. Demographic responses of an extremophile crustacean to environmental factors: Great Salt Lake (Utah, USA) brine shrimp (Artemia franciscana)
11
Canadian Journal of Fisheries and Aquatic Sciences. The effects of salinity on plankton and benthic communities in the Great Salt Lake, Utah, USA: a microcosm experiment
12
Geosites. Use of remote imagery to map microbialite distribution at Great Salt Lake, Utah: Implications for microbialite exposure
13
PLOS Water. Desiccation of ecosystem-critical microbialites in the shrinking Great Salt Lake, Utah (USA)
14
Atmospheric Environment. Metal mobility and bioaccessibility in Great Salt Lake dust and exposure risks for humans and food crops
15
PubMed Central. Pro-inflammatory effects of inhaled Great Salt Lake dust particles
16
PubMed Central. Contributions of Great Salt Lake Playa- and Industrially Sourced Priority Pollutant Metals in Dust Contribute to Possible Health Hazards in the Communities of Northern Utah
17
Environmental Research Letters. Implications of a shrinking Great Salt Lake for dust on snow deposition in the Wasatch Mountains, UT, as informed by a source to sink case study from the 13–14 April 2017 dust event
18
Environmental Research Communications. Estimated energy and emissions impacts of pumping Pacific Ocean water to Great Salt Lake
19
SAGE Journals (Environment and Behavior). Concerns About the Drying Great Salt Lake: What Do People Care About and Who Cares the Most?