Researchers have identified a vast freshwater reservoir beneath the hypersaline surface of Utah’s Great Salt Lake, potentially covering an area equivalent to around 500,000 football fields. The underground water body, situated approximately 3 to 4 kilometers (about 10,000 to 13,000 feet) below the surface, challenges prior assumptions about the lake’s subsurface composition.
Using advanced airborne electromagnetic (AEM) surveys, scientists from the University of Utah created detailed 3D images of the lake’s geological structure. This innovative technique allowed them to differentiate between saltwater and freshwater based on electrical resistivity, revealing the presence of significant freshwater saturation within sediments beneath the lake.
Published in Scientific Reports, a journal affiliated with Nature, the study highlights that the freshwater extends deep into the sediments beneath the hypersaline surface. Lead researcher and geology professor Michael Zhdanov explained, “By understanding the depth and extent of this potential reservoir, we can estimate its volume and implications for water resources.”
Bill Johnson, a hydrologist and co-author of all recent Great Salt Lake groundwater studies, noted that the freshwater appears to be entering the subsurface from the lake’s interior rather than from its periphery. During a recent appearance on KPCW’s Cool Science Radio, Johnson said, “What’s surprising is that the freshwater extends so far inward, possibly under the entire lake. It’s not just confined to the edges, as we’d typically expect.”
He added, “Hydrologists usually anticipate that the denser brine would occupy the entire subsurface volume, with freshwater coming in from the mountains at the edges. Instead, we’re seeing deep volumes of freshwater moving inward beneath the saline lens.”
The discovery holds significant potential for water management strategies, especially in combating dust pollution on the exposed lakebed. Experts suggest that harnessing this underground freshwater could help wet the lakebed without disrupting the existing saline system, offering a promising avenue for sustainable water use in the region.