Environment

A Virtual 3D Satellite Fly-Over of Utah's Once Great Salt Lake Reveals Shocking Shrinkage

Thanks to overuse of water and drought, the lake has shrunk to a record low level, revealing lakebed sediments contaminated with toxic materials.

ImaGeo iconImaGeoBy Tom YulsmanJul 22, 2022 8:30 PM
Great Salt Lake 3D
This simulated 3D view of the Great Salt Lake is based on satellite data collected on July 9, 2022. Much of the lighter colored land around the lake once was covered with water. See below for a virtual flyover of the lake. (Credit: Copernicus Sentinel data processed by Tom Yulsman)

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The Great Salt Lake is not nearly as great as it once was.

On July 3, 2022, the U.S. Geological Survey reported that it had reached its lowest level in 175 years of record keeping. Lake levels will likely continue to drop until fall or early winter, when water flowing into the lake should at least equal what's lost through evaporation.

“This is not the type of record we like to break,” says Joel Ferry, Executive Director of Utah's Department of Natural Resources, in a public statement. “Urgent action is needed to help protect and preserve this critical resource. It’s clear the lake is in trouble."

To help convey just how much trouble the lake is in — along with the millions of people who live near it — I've put together a series of images, some that I took along the shore of the lake on July 9, and others acquired by satellite. This imagery includes a virtual 3D flyover of the lake I created using satellite data acquired on the same day. Please keep reading for that video.

Starved of Fresh Water

When it is full to its historic average level of 4,200 feet above sea level, the lake spreads across 1,700 square miles — that's nearly the size of the state of Delaware. This makes it the Western Hemisphere'a largest saltwater lake.

Its level ebbs and flows naturally with the seasons and changing weather conditions. And that ebb and flow once was in relative balance. Large amounts of water would evaporate with warm summer weather, causing the lake level to drop. Then in spring, runoff from melting snowpack in the Wasatch Range to the east replenished the lake with copious fresh water flows.

As farmers, industry and the fast-growing cities of the Wasatch Front, including Salt Lake City, have diverted more and more water from the rivers coursing down from the mountains, the balance has been upset. A study published in 2017 showed that consumptive use of water had lowered the lake by 11 feet and reduced its volume by 48 percent.

In recent years, relatively thin snowpack plus increased evaporation due to warmer temperatures, have taken an increasing toll. Over the long term, the southwestern quadrant of the United States, which includes Utah, has been gripped by a profound megadrought — the worst in at least 1,200 years. Research has shown that 42 percent of this megadrought is due to human-caused climate change. 

Before and after satellite images reveal the shocking shrinkage of the Great Salt. The before image was acquired by NASA's Terra satellite on July 11, 2000. The after image was captured by the Aqua satellite on July 11 of this year. (Credit: Images from NASA Worldview. Animation by Tom Yulsman)

As a result, the Great Salt Lake has lost much of its greatness, shriveling by two-thirds. The animation of satellite images above drives that sobering fact home.

So does this photograph, taken on July 9 from the south shore of the lake at Great Salt Lake State Park:

Looking east from Great Salt Lake State Park on July 9, 2022, a vast expanse of former lakebed stretches into the distance. (Credit: ©Tom Yulsman)

Not long ago, the vast expanse of light-colored sediment extending to the west from where the two people in the photo above are walking was all underwater.

Off in the distance, about a mile and a half away across the exposed lakebed, you can spot a landmark known as the Great Salt Air. It's in the middle of the right edge of the frame. Currently an entertainment venue, a lakeside resort once stood there:

The Great Salt Air resort, circa 1900. This structure burned down in 1925. The current building on the site, built in 1981 — and flooded by the lake a few years later — was once at the edge of the water. (Credit: Public domain photo via Wikipedia)

And here's the view from the Great Salt Air site today:

The view toward the lake from the back of the Great Salt Air entertainment venue. People once bathed here. Now, the water is more than a half mile away. (Credit: ©Tom Yulsman)

As you can see, it's now a very long walk from the Great Salt Air to the shore of the lake.

Virtual Satellite Flyover

The large expanse of formerly submerged lake bed at the south end of the Great Salt Lake is just a small portion of what's been exposed in recent years. To see the full extent of it, in a dynamic format, check out the virtual flyover I created (with narration) using Sentinel 2 satellite data:

As I mention in the voice-over to the video, research shows that the lakebed sediments harbor harmful contaminants, much of which originated from mining activities in the region. Among the most concerning is arsenic, but there's a veritable witch's brew of many others, including copper, sulfur, silver, phosphorous, chlorine, molybdenum, zirconium, lead, barium, magnesium, uranium, calcium, cobalt, selenium, zinc, antimony and lithium.

The concern is that winds could pick up arsenic — known to cause cancers of the lung, urinary bladder, kidney, liver and skin — and other toxic materials from the dry lake bed and spread it over Salt Lake City and other populated areas of the Wasatch Front.

How big is the risk?

Most of the exposed lakebed containing the contaminants is protected by a crusty surface layer. But a systematic survey conducted between 2016 and 2018 of the 757 square miles of then-exposed lakebed yielded worrisome results: All major areas of exposed lakebed contained "hot spots" where winds could easily kick up dust tainted with arsenic and other toxic materials.

“This is a disaster,” says Kevin Perry of the University of Utah, lead researcher on the survey, quoted in a recent New York Times story. “And the consequences for the ecosystem are absolutely, insanely bad.”

I'll get back to those ecosystem impacts in a minute, but first, just how much of a problem are these hot spots?

Perry and his colleagues found that nearly a tenth of the exposed lakebed was made up of hot spots that produce dust plumes under windy conditions. The researchers also found that high wind events capable of producing substantial dust plumes occurred on about 44 days of every year. In fact, dust plumes from the Great Salt Lake already are known to impair air quality in Salt Lake City, posing a significant public health risk.

Should the lake continue to fall — which is all but inevitable unless water consumption is curbed — the number of dust hot spots in a broad area of the southern portion of the lake would increase.

And even without further declines in the lake's level, hot spots would increase as people ventured out onto the already exposed lakebed, further disturbing the surface crusts. Ultimately, the researchers found that these disturbances, plus reductions in plant cover protecting the crusts, could make more than a fifth of the lakebed vulnerable to producing dust plumes.

Mining Operations on the Shore of the Lake

Since the 1860s, copper and other valuable ores have been mined from the Bingham Mining District in the Oquirrh Mountains just south of the lake. The district includes Kennecott's giant Bingham Canyon open pit copper mine. It's one of the largest and highest producing mines in the world.

A simulated 3D view of Kennecott's Bingham Canyon Mine, created using image data acquired by the Sentinel 2 satellite on July 16, 2022. It's considered to be the largest open pit mine in the world. (Credit: Copernicus Sentinel data modified by Tom Yulsman)

Over many decades, mining wastes containing arsenic and other toxic materials have caused contamination of soils, surface waters, and ground water, leading to several U.S. EPA Superfund cleanup efforts. Moreover, some contaminants appear to have found their way into lakebed sediments at the southern end of the Great Salt Lake.

One possible source is dust blowing over the lake from Kennecott's massive mine waste, or "tailings," impoundment along the south shore. The waste is what's left after the copper ore is extracted.

In their report, Kevin Perry and his colleagues note that despite Kennecott's efforts at dust suppression, high winds commonly kick up big plumes from the tailings pile.

A simulated 3D view of Kennecott's gigantic complex of mine waste piles, with Salt Lake City beyond it to the east. The view was created using image data acquired by the Sentinel 2 satellite on July 16, 2022. The entire complex is more than half the size of Manhattan Island. Grayish colored waste and a blue impoundment pond of the active waste site are clearly visible. (Credit: Copernicus Sentinel data modified by Tom Yulsman)

"There is evidence that some of this fugitive dust is deposited onto the adjacent lakebed," they write. In fact, the team found that four elements — copper, silver, molybdenum and sulfur — peaked in samples taken in the area immediately north of Kennecott's tailings impoundment.

When I visited the area on July 9, it was a particularly windy day. And sure enough, I observed big dust plumes being kicked up from the mine tailings. This was happening despite the efforts of giant sprinklers to keep the dust down.

Under high winds on July 9, 2022, dust swirls up from embankments of a giant mining waste impoundment on the south shore of the Great Salt Lake. The waste, or tailings, comes from a nearby Kennecott copper mining operation. The stack in the distance is part of the ore smelting facility. It's almost as tall as the Empire State Building. (Credit: ©Tom Yulsman)

You can see a small portion of the 250-foot-high tailings impoundment in the photo above. The dust is coming from giant embankments built from coarse mining waste. Finer waste is held in a watery impoundment out of sight in this photo. Using satellite imagery, I estimate that the entire complex of tailings impoundments here is now greater than half the size of the island of Manhattan.

A Coming Ecological Calamity?

The prospect of toxic dust blowing out over Salt Lake City and other communities is bad enough. Scientists and conservationists are also worried about another looming problem.

As the lake shrinks and becomes saltier from lack of fresh water inflows, 10 million migratory birds that stop there to feed are under threat. That's because the changes are disrupting vital wetlands and other habitats, and also stressing the food sources the birds depend on.

Among those food sources is this little critter:

Brine shrimp are part of the foundation of the Great Salt Lake's food web. (Credit: ©Tom Yulsman)

It's a brine shrimp — a half-inch-long crustacean that's hungrily consumed by migrating birds. The problem is that when the salinity of the lake crosses a critical threshold, which the N.Y. Times has reported could happen as early as August, algae that brine shrimp feast on will struggle to survive. If the population of algae crashes, so would the brine shrimp. And that would be a true ecological calamity.

Among the many migratory birds that depend on brine shrimp are Wilson's phalaropes. More than half a million of these birds have been counted on the lake in a single day. That's greater than half of the world's entire population! While there, they gorge on the tiny shrimp, as well as copious clouds of brine flies. This enables them to nearly double their body weight before they head off on a 5,400 mile migratory journey.

A California Gull swoops low over the water at Great Salt Lake State Park on July 9, 2022, possibly looking for brine flies to feed on. Believe it or not, the California Gull is Utah's state bird! (Credit: ©Tom Yulsman)

As many as 1.7 million Eared Grebes — nearly half of the entire North American population — spend time at the Great Salt Lake to grow new feathers. They get the calories they need for this molting process by eating large amounts of brine shrimp.

While they are molting, they cannot fly, making them vulnerable to predators. Luckily, habitats along the Great Salt Lake provide something of a haven from red foxes, coyotes, bobcats and other mammals that might pose a threat. But that could change as the lake continues to shrink and land habitats shift as a result.

The solution is straightforward in concept, but very difficult to realize in practice: Use less water so more can flow into the lake.

Per-capita water use in Utah is the second highest in the United States and is more than two and a half times higher than in other semi-arid parts of the world. Clearly, there's lot's of room for conservation. But efforts to pass legislation and enact policy reforms that would significantly reduce water use have had mixed results. At least so far.

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