Great Salt Lake is shrinking, revealing fascinating secrets

Measurements of one of the largest saltwater lakes in the world show that for more than 40 years its water level has been dropping and its surface area shrinking. The Great Salt Lake is now 60 percent smaller than it was a few decades ago. Recently it turned out that the exposed lakebed hides unusual oases, where fresh water springs emerge to feed the lake. Scientists see them as a chance to restore the ecosystem’s balance.

Where does the fresh water in the Great Salt Lake come from?

The decline of the Great Salt Lake is a decidedly negative phenomenon that threatens the balance of the local ecosystem. A study published last year in One Earth showed that the dry lakebed in 2020 emitted 4.1 billion tons of carbon dioxide and other greenhouse gases. The exposed surface also contains elements harmful to health: arsenic, lead, and mercury.

Yet the drying lake hides more secrets. They are gradually being uncovered by geologists from the University of Utah. Their attention was drawn to distinctive oases – round mounds covered with reeds. Professor Bill Johnson of the University of Utah’s Department of Geology and Geophysics suspects that an underground hydraulic system lies beneath the surface. These vegetated spots are points where water was pushed to the surface under pressure.

Electromagnetic measurements carried out using a helicopter-borne antenna showed that groundwater supplies the Great Salt Lake to a much greater extent than previously assumed – not 3 but 12 percent. Prof. Johnson suspects that there may be hundreds of such mounds hiding springs. It still remains unclear, however, where the underground fresh water comes from.

This issue interests scientists primarily because of problematic emissions of greenhouse gases and carcinogenic substances. The reserves of fresh water under the lake basin are seen as a chance to restore the lake and reduce the harmful dust carried by winds from the exposed bottom. According to scientists in Utah, the whole operation would have to be carried out with great caution so as not to damage the surrounding wetlands.

Great Salt Lake – an important part of the ecosystem and the American economy

Located in Utah, the Great Salt Lake is the largest saline body of water in the United States. Among the world’s salt lakes, it ranks eighth in size. Scientists from NASA’s Earth Observatory emphasize that its shallow waters provide rest for millions of birds during seasonal migrations.

The Great Salt Lake is also of considerable economic importance. Its waters are intensively harvested for brine shrimp, magnesium is extracted, and salt is obtained. All these activities generate around $1.5 billion annually for the U.S. economy.

40 years and almost 7 meters less – why is the water level dropping so rapidly?

Utah officials point to two main reasons for the Great Salt Lake’s difficult situation: climate change and increased demand for water for residents and economic purposes. As a result of climate change, less water from mountain streams reaches the lake. Scientists from Utah State University calculated that since 1850 inflows have decreased by 39 percent. In addition, as researchers from NASA’s Earth Observatory note, the Great Salt Lake is increasingly fed by intense rainfall rather than by the slow, steady melting of snowpack.

Outflows, on the other hand, are increasing. Currently, 63 percent of the water withdrawn from the lake is used by agriculture, 13 percent by solar evaporation ponds that produce energy, 11 percent by cities, and the remaining 13 percent for other purposes.

These adverse changes have caused the water level of the Great Salt Lake to fall by about 6.70 meters since 1986, while its surface area has shrunk by as much as 60 percent. State authorities have long emphasized that restoring the lake should now be a priority. However, politicians lack consensus on how to achieve it. The recently discovered oases offer new perspectives in this regard.

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main photo credit: John Morgan/Flickr