Ютагийн их сургуулийн судлаачид Их давст нуурын доор гүний цэвэр усны асар том систем байгааг тогтоожээ.
Фармингтон буланд хийсэн судалгаагаар нуурын давстай хөрсний дор 3-4 километрийн гүнд цэвэр ус бүхий тунадас үе давхарга үүссэн болохыг илрүүлсэн байна. Эрдэмтэд 2025 оны хоёрдугаар сард нисдэг тэргэнд суурилуулсан цахилгаан соронзон (AEM) хэмжилтийн төхөөрөмж ашиглан газрын доорх бүтцийг зураглажээ. Давстай ус нь цэвэр уснаас илүү сайн цахилгаан дамжуулдаг зарчмыг ашиглан давс болон цэвэр усны заагийг ялган тогтоосон байна.
Судалгааны багийн ахлагч, профессор Майкл Ждановын тайлбарласнаар, энэ нь нуурын гадаргуу дахь нимгэн давстай үеийн доорх цэвэр усыг илрүүлэхэд AEM аргыг амжилттай ашигласан анхны тохиолдол болжээ. Уг цэвэр ус нь нуурын эрэг орчмоор хязгаарлагдахгүй, нуурын төв хэсэг рүү гүн түрэн орсон байдалтай байна. Мөн Фармингтон булангийн хөрсөн дээрх зэгс бүхий дугуй хэлбэрийн довцог нь газрын гүний цэвэр ус дээш түрэн гарч ирж буй цэгүүдтэй давхцаж байгааг тогтоосон нь эрдэмтдийн анхаарлыг татжээ.
Энэхүү нээлт нь Их давст нуурын түвшин буурснаас үүдэлтэй хортой тоосжилтын асуудлыг шийдвэрлэхэд чухал ач холбогдолтой юм. Судлаач Билл Жонсоны үзэж буйгаар, газрын гүний энэхүү усыг ашиглан тоосжилт ихтэй газар нутгийг чийгшүүлэх боломжтой бөгөөд энэ нь нуурын ёроолыг бүхэлд нь усаар дүүргэхээс илүү бодит бөгөөд практик шийдэл байж болох юм. Цаашид уг судалгааг нуурын 1,500 хавтгай дөрвөлжин миль талбайг бүрэн хамруулан өргөжүүлэхээр төлөвлөж байна.
Дэлгэрэнгүйг эх сурвалжаас харах
↓Эх сурвалжийг нээх ↓
Circular mounds of tall reeds rising from the dried-out floor of Farmington Bay first caught researchers’ attention a few years ago. The mounds, each 50 to 100 meters across and covered in phragmites reeds reaching about 15 feet, were forming where freshwater pushed upward under pressure through gaps in the impervious layer beneath the lake’s exposed playa. That observation sent University of Utah geophysicists searching for the source, and what they found was far larger than expected.
A study published in the journal Scientific Reports describes a deep underground freshwater system filling sediments beneath the Great Salt Lake’s hypersaline surface. Using airborne electromagnetic (AEM) surveys conducted in February 2025, researchers mapped the saline-freshwater boundary beneath Farmington Bay and the northern part of Antelope Island, finding freshwater-saturated sediments extending from shallow depths down to 3 to 4 kilometers, roughly 10,000 to 13,000 feet below the surface.
Airborne Surveys Measure What Lies Below the Salt
To carry out the surveys, the University of Utah team contracted a Canadian geophysical crew to fly electromagnetic instruments suspended beneath a helicopter. The aircraft completed 10 east-west flight lines across Farmington Bay and northern Antelope Island, covering 154 miles in total. The equipment measured electrical resistivity at depths of up to about 100 meters, a technique that separates freshwater from brine because saltwater conducts electricity far more readily than freshwater does.
Lead author Michael Zhdanov, a distinguished professor of geology and geophysics and director of the Consortium for Electromagnetic Modeling and Inversion (CEMI) at the University of Utah, says this marks the first demonstrated use of AEM methods to detect freshwater beneath the thin conductive saltwater layer at the surface of the Great Salt Lake.
The resulting maps showed a sharp contrast: a saline layer near the surface giving way, just 10 meters down, to resistive freshwater that appears to extend across the survey area. One of the phragmites mounds on the playa sat directly above a point where freshwater breached the impermeable layer and rose toward the surface.
Freshwater Extends Toward the Lake’s Interior, Not Just Its Edges
The pattern the data revealed surprised the research team. Under normal hydrological assumptions, denser brine would occupy the full volume beneath a terminal lake like the Great Salt Lake, with freshwater from surrounding mountains entering only at the margins. The surveys suggest something different is happening here.
Hydrologist and co-author Bill Johnson, a professor of geology and geophysics, described the unexpected finding on KPCW’s Cool Science Radio: the freshwater beneath the lake extends well into the lake’s interior rather than staying near the periphery, and a deep volume of it appears to be moving inward beneath the saline lens. Whether this pattern holds beneath the full extent of the lake remains unknown, as the pilot study covered only a portion of the southeastern margin.
Zhdanov’s group at CEMI also applied a complementary technique, combining the AEM data with magnetic measurements to build 3D tomographic images of the subsurface. The magnetic data inversion revealed that the basement beneath the Farmington Bay playa sits at less than 200 meters depth, but then drops abruptly to 3 to 4 kilometers. This structural boundary falls directly beneath one of the reed-covered mounds and marks a geological transition the researchers say warrants further mapping.
A Potential Tool Against Toxic Dust Pollution
The practical stakes of understanding this aquifer connect directly to a public health problem. As Great Salt Lake water levels have fallen, roughly 800 square miles of lake playa have been exposed, generating dust that blows into Utah communities. That dust carries toxic metals, and conventional efforts to flood or re-wet the playa at scale face serious limitations.
Johnson and his colleagues are now exploring whether the artesian groundwater rising through the lake floor could be carefully used to dampen dust hotspots on the exposed playa without significantly disrupting the underground system. As he described it, wetting specific dust emission sites with this groundwater represents a practical near-term option, particularly in areas where reflooding large sections of the playa remains unlikely.
The current work is part of a broader research effort led by the University of Utah’s Department of Geology and Geophysics and funded by the Utah Department of Natural Resources and the Great Salt Lake Commissioners’ Office. Two additional studies have already emerged from this project, according to the University of Utah’s research office, with more expected as the work continues.
If the AEM approach can be scaled to cover the lake’s full 1,500-square-mile footprint, the data would give water resource planners a far clearer picture of what lies beneath one of the Western Hemisphere’s largest terminal lakes.
Enjoyed this article? Subscribe to our free newsletter for engaging stories, exclusive content, and the latest news.
