In 2022, the Great Salt Lake, which is the largest saltwater lake in the Western Hemisphere, hit historic low water levels, leading to worries about economic, ecological, and public health issues in Utah. Recent research from Portland State University is considered the first peer-reviewed study that measures the factors contributing to these unprecedented low water levels, which the researchers highlight as vital for predicting and managing future changes to the lake.
“The lake holds significant social and economic importance for Utah and the surrounding region,” explained Siiri Bigalke, the lead author and a Ph.D. candidate in PSU’s Earth, Environment, and Society program, who expanded on research she began while pursuing her master’s degree at Utah State University. “It generates over $1.9 billion in economic revenue each year, acts as a crucial feeding ground for millions of migratory birds, and contributes to increased snowfall in the Wasatch Mountain Range,” which is home to 11 top-tier ski resorts, a key reason the 2034 Winter Olympics will be held again in Salt Lake City.
Bigalke, along with co-authors Paul Loikith, an associate professor of geography and director of PSU’s Climate Science Lab, and Nick Siler, an associate professor in the College of Earth, Ocean, and Atmospheric Sciences at Oregon State University, created and utilized a model to track changes in lake volume on an annual basis, focusing on water sources primarily from streamflow and precipitation into the lake, alongside evaporation from the lake’s surface.
“We designed a model that allowed us to explore different scenarios by changing just one of the input or output variables to understand the specific contributions of streamflow, precipitation, and evaporation to the lake’s record low volume in 2022,” Bigalke noted.
The drop in lake levels preceding 2022 has largely been linked to reduced stream flows from the lake’s three main tributaries, which are likely affected by a mix of drought, water diversions, and climate change. However, this study discovered that declines in streamflow only explained approximately two-thirds of the total reduction in lake volume, with the remainder primarily resulting from increased evaporation due to rising temperatures—a trend expected to worsen with ongoing climate change.
“With the climate warming, the rate of evaporation from the lake increases, making this warming’s impact on evaporation substantial,” Loikith stated. “Without the warming trend, 2022 would not have recorded such low levels. While streamflow plays a major role, the spike in evaporation was crucial to achieving this record low.”
The researchers indicated that their findings imply that improved streamflow could lead to quick recovery in lake volume in the short term, but if warming continues, evaporation is likely to cause further long-term water loss.
Beyond ecological and economic concerns, a shrinking lake also creates health hazards by exposing toxic dust, affecting the 1.2 million residents in the Salt Lake City metropolitan area.
“As the lake diminishes, dry areas of the lakebed become exposed, potentially leading to more dust storms in the city, which can degrade air quality for local inhabitants,” Bigalke elaborated.
The results of this study were published in the journal Geophysical Research Letters. The authors recommend additional research to assess the extent of local changes in evaporation, variations in precipitation, and human-driven diversions influencing streamflow into the lake.
