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University of Utah Discovers Vast Freshwater Reservoir Beneath Great Salt Lake
· Confirmed
In Short: Researchers from the University of Utah have discovered a vast reservoir of freshwater hidden beneath the Great Salt Lake playa, according to a new study published in Attheu.
Researchers from the University of Utah have discovered a vast reservoir of freshwater hidden beneath the Great Salt Lake playa, according to a new study published in Attheu. The study, which used airborne electromagnetic (AEM) surveys, revealed that freshwater saturates the sediments beneath the lake’s hypersaline surface to depths of 3 to 4 kilometers, or about 10,000 to 13,000 feet.
The latest paper measured electrical resistivity to a depth of about 100 meters via airborne electromagnetic surveys to discern freshwater from brine, which is far more electrically conductive. This method allowed researchers to identify a continuous freshwater reservoir layer stretching from about 330 feet (100 meters) down to 2.5 miles (4 kilometers).
The Great Salt Lake has dropped by about 22 feet (6.7 meters) since 1986, driven by drought, climate conditions, and water use. This decline has exposed 800 square miles of lake playa, which is now becoming a major source of dust pollution blowing into Utah’s population centers.
The unexpected part of this discovery wasn't the salt lens that researchers see near the surface across the playa. It's that the freshwater underneath it extends so far in towards the interior of the lake and possibly under the entire lake, said Bill Johnson, a co-author of the study and hydrologist at the University of Utah.
Suspicions of the subterranean freshwater reservoir first arose with the sudden appearance of strange reed-covered islands, each 50 to 164 feet in diameter, in the dried-out lakebed. These islands were manifestations of freshwater welling up under pressure at several spots on the lake’s exposed playa in Farmington Bay.
Researchers from the US analyzed a 120-meter (394-foot) sediment core taken from the lake bed, dating its layers by the radioactive decay of the minerals it carried. This analysis provided insights into the lake’s past, identifying bigger bodies of water such as Lake Bonneville and Little Valley.
The study, detailed in Scitechdaily, indicates that this groundwater fills tiny pore spaces within sediments west of the Wasatch Mountains, lying beneath a salty layer roughly 30 feet thick. This previously unknown zone is now referred to as the “saltwater lens,” and its discovery is reshaping scientists’ understanding of subsurface water flow in the region.
There are beneficial effects of this groundwater that we need to understand before we go extracting more of it,” said Johnson. “A first-order objective is to understand whether we could use this freshwater to wet dust hotspots and douse them in a meaningful way without perturbing the freshwater system too much.
Suspicions of the subterranean freshwater reservoir first arose with the sudden appearance of strange reed-covered islands, each 50 to 100 meters (164 to 328 feet) in diameter, in the dried-out lakebed, which spans approximately 1,000 square kilometers (386 square miles).
Background
Researchers from the University of Utah have discovered a vast reservoir of freshwater beneath the Great Salt Lake, according to a new study published in Attheu.
Researchers from the University of Utah have discovered a significant body of freshwater hidden beneath the Great Salt Lake playa, a finding that could reshape our understanding of subsurface water flow in the region.
What's confirmed
- “There are beneficial effects of this groundwater that we need to understand before we go extracting more of it. A first-order objective is to understand whether we could use this freshwater to wet dust hotspots and douse them in a meaningful way without perturbing the freshwater system too much,” Johnson said.
- “We were able to answer the question of how deep this potential reservoir is, and what its spatial extent is beneath the eastern lake margin. If you know how deep, you know how wide, you know the porous space, you can calculate the potential freshwater volume,” said lead author Michael Zhdanov, a geophysicist at the University of Utah, in a statement about the work.
- “The unexpected part of this wasn't the salt lens that we see near the surface across the playa. It's that the freshwater underneath it extends so far in towards the interior of the lake and possibly under the entire lake. We don't know,” Bill Johnson, a co-author of the study and hydrologist and the University of Utah, said on a recent appearance on KPCW’s Cool Science Radio show.
What's still developing
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- “What we would normally expect as hydrologists is that the brine would occupy the entire volume underneath that lake,” he explained in an interview on KPCW’s Cool Science Radio show, cited in the university release.
- The findings, detailed in a new study in the journal Scientific Reports, upend expectations that any freshwater presence would be small and relegated to the lake’s outskirts, dumped there by nearby mountains.
- Recently, upward hydraulic gradients of fresh groundwater (average conductivity of 0.091 S/m) have been observed in nested piezometers beneath the study site with a thin layer of hypersaline water (conductivity up to 15 S/m) near the surface observed both in nested piezometers and pore waters extracted from sediment cores 4, 5.
- Moreover, more than 300 offshore freshened groundwater (OFG) reservoirs have recently been identified 7 using drilling, geochemical, and geophysical methods.
- While ground electromagnetic and electrical resistivity surveys have been used to investigate OFGs (e.g., a magnetotelluric survey of deep freshwater reserves beneath salinity-stressed coastal Bangladesh reported in 10 ), airborne methods in groundwater exploration have typically been confined to shallow depths (~ 10–40 m) in conductive ground 11.
- In a study published in Blood, scientists identified over 3,775 proteins in mature human red blood cells, revealing a surprisingly dynamic network that adapts quickly to changing oxygen levels.
- His team also characterized the spatial extent of the freshwater reservoir beneath Farmington Bay and studied the potential depth of freshwater-saturated sediments by delineating the basement structure.