Utah Scientists Find Massive Freshwater Reserve Under Salt Lake

Scientists have found something unexpected beneath one of America's saltiest lakes: a massive reservoir of fresh water that could help save the shrinking Great Salt Lake.

Researchers at the University of Utah discovered the underground freshwater layer while investigating mysterious reed-covered mounds sprouting from dried patches of the lake bed. Since these reeds need abundant fresh water to survive, the team suspected groundwater was rising from below.

To solve the mystery, scientists conducted an airborne electromagnetic survey over a 10-square-mile section of the lake. They flew a helicopter with a circular device that sent electromagnetic pulses downward, mapping what lay beneath the salt water and sediment.

The results amazed them. Fresh water saturates the sediments across the entire survey area, extending from 330 feet deep to 2.5 miles in some spots. The water likely accumulated over thousands or even millions of years as snowmelt trickled down from surrounding mountains.

"When I first realized that we found this, I was very excited," said study lead author Michael Zhdanov, a geology and geophysics professor at the University of Utah. "I think it's very important."

The discovery comes at a critical time for Great Salt Lake. Since 1986, the lake has dropped about 22 feet due to human water consumption, drought, and climate change. Exposed sections of lake bed have dried and cracked, creating clouds of toxic dust that threaten nearby communities.

Why This Inspires

This hidden water source offers real hope for restoration. If future surveys confirm the reservoir extends beneath the entire 1,700-square-mile lake, it could provide a solution to the toxic dust problem plaguing dried-up sections.

The research team suspects a layer of cap rock prevents the fresh water from mixing with the salt water above, though more study is needed. Watertight basement rocks form the lower boundary of the reservoir, with faults in these rocks explaining why the depth changes so dramatically.

The team plans to expand their survey across the entire lake to confirm the reservoir's full extent. What started as a small pilot project to test whether electromagnetic pulses could penetrate salt water has revealed something potentially transformative for Utah's water future.

Sometimes the solutions we need are hiding right beneath our feet.