A newly recognized underground freshwater system beneath the Nice Salt Lake is changing into clearer because of a examine that used airborne electromagnetic (AEM) surveys to map geologic formations beneath Farmington Bay and Antelope Island alongside the lake’s southeastern edge.
Researchers from the College of Utah analyzed the info and located that freshwater fills sediments beneath the lake’s extremely salty floor, reaching depths of three to 4 kilometers, or about 10,000 to 13,000 toes. The helicopter-based survey was carried out final 12 months after scientists noticed freshwater rising beneath strain in components of the uncovered lakebed in Farmington Bay, forming uncommon mounds lined in dense phragmites reeds.
In response to lead writer Michael Zhdanov, the examine marks the primary time AEM know-how has efficiently detected freshwater beneath the skinny layer of conductive saltwater on the floor of the Nice Salt Lake. The crew additionally mapped how far the freshwater extends beneath Farmington Bay and estimated how deep the water-saturated sediments go by figuring out the underlying basement construction.
“We had been capable of reply the query of how deep is that this potential reservoir, and what’s its spatial extent beneath the jap lake margin. If you understand how deep, you understand how vast, you understand the porous house, you’ll be able to calculate the potential freshwater quantity,” mentioned Zhdanov, a distinguished professor of geology & geophysics and director of the Consortium for Electromagnetic Modeling and Inversion, or CEMI.
State-Funded Analysis on a Newly Found Aquifer
The findings had been printed within the Nature-affiliated journal Scientific Reviews. This work is a part of a broader analysis initiative led by the College of Utah’s Division of Geology & Geophysics and funded by the Utah Division of Pure Sources. The purpose is to higher perceive groundwater beneath the Nice Salt Lake, the biggest terminal lake within the Western Hemisphere.
Senior college and graduate college students have contributed to this ongoing effort, which has already produced two extra research, with extra anticipated.
The brand new outcomes point out that freshwater could also be transferring into the subsurface towards the lake’s inside fairly than staying close to the perimeters, which is what scientists sometimes count on. Hydrologist Invoice Johnson, a co-author on the groundwater research, highlighted how uncommon this sample is.
“The surprising a part of this wasn’t the salt lens that we see close to the floor throughout the playa. It is that the freshwater beneath it extends up to now in in the direction of the inside of the lake and probably beneath the whole lake. We do not know,” Johnson mentioned on a latest look on KPCW’s Cool Science Radio present. “What we might usually count on as hydrologists is that that brine would occupy the whole quantity beneath that lake. It is denser than the freshwater. You’d count on the freshwater from the mountains to return in someplace on the periphery. However we discover it is coming in in the direction of the inside. And there is what seems to be deep quantity of this freshwater coming in beneath that saline lens.”
Freshwater Might Assist Scale back Poisonous Mud
The analysis was prompted by the looks of round mounds on the dried lakebed in Farmington Bay over latest years. These options measure 50 to 100 meters throughout and are lined in tall reeds reaching about 15 toes. As water ranges within the lake have dropped, round 800 sq. miles of uncovered lakebed have grow to be a rising supply of mud air pollution affecting close by communities.
Johnson and his colleagues are investigating whether or not the artesian groundwater may very well be used safely to cut back mud, which comprises dangerous metals.
“There are helpful results of this groundwater that we have to perceive earlier than we go extracting extra of it. A primary-order goal is to know whether or not we might use this freshwater to moist mud hotspots and douse them in a significant approach with out perturbing the freshwater system an excessive amount of,” Johnson mentioned. “To me, that is a main goal as a result of it’s totally sensible and it is unlikely we’ll be capable of fill Farmington Bay and different components of the playa sufficient to keep away from some mud spots showing on the increased elevations. This may be an effective way to get at that.”
Johnson, together with colleagues together with Mike Thorne and Kip Solomon, is in search of funding to broaden the analysis to cowl a bigger portion of the lake.
Airborne Surveys Reveal Subsurface Construction
On this examine, scientists used airborne electromagnetic surveys to measure electrical resistivity right down to about 100 meters, permitting them to differentiate freshwater from saltwater, which conducts electrical energy extra simply. To hold out the work, Johnson and Zhdanov employed a Canadian geophysical crew to fly devices suspended beneath a helicopter in February 2025. The plane accomplished 10 east-west survey strains throughout Farmington Bay and the northern a part of Antelope Island, protecting a complete of 154 miles.
Zhdanov’s crew used the info to map the place freshwater meets saline water underground. One of many reed-covered mounds was positioned immediately above a degree the place freshwater was rising by means of a break within the impermeable layer beneath the lake.
“Purple means very conductive, blue is resistive,” Zhdanov mentioned whereas explaining the map. “You clearly see close to floor is saline water, 10 meters beneath is resistive freshwater. You see clearly it is all over the place.”
3D Imaging Reveals Deep Geological Options
The CEMI analysis group developed a way to create detailed 3D photographs of the subsurface by combining airborne electromagnetic knowledge with magnetic measurements. Utilizing this strategy, the crew produced a tomographic mannequin extending deep beneath Farmington Bay, providing new perception into the world’s geological and hydrological framework.
Their evaluation reveals that the basement beneath the playa is comparatively shallow, lower than 200 meters deep, earlier than dropping sharply to depths of three to 4 kilometers. This abrupt transition happens beneath one of many phragmites mounds and marks a serious structural boundary that warrants additional investigation.
“That is why we have to survey the whole Nice Salt Lake. Then we’ll know the highest and the underside,” Zhdanov mentioned. “To check the highest we use airborne electromagnetic strategies, which supplies us the thickness of the saline layer and the place the freshwater begins beneath the saline layer. To check the underside, we use magnetic knowledge. We use completely different strategies to check the vertical extent of this freshwater-saturated sediments, to search out the depth to the basement.”
Though this preliminary examine lined solely a small part of the lake, Zhdanov believes it’s possible to increase airborne surveys throughout the lake’s full 1,500-square-mile space.
A complete survey might help regional water administration selections and assist information related efforts to find freshwater beneath terminal lakes all over the world.
