(Google) The Great Salt Lake used to cover nearly 1,500 square miles, in 2021 it covers just 937. This composite photograph shows satellite images from the years 1986 through 2016.
The salty water of the Great Salt Lake is up compared to the past few water years, but it’s still a puddle of its former self, rimmed by vast reaches of exposed lake bed.
The lake’s size fluctuates naturally with seasonal and long-term weather patterns, but the lake has been experiencing decline for decades as Utahns take water out of rivers and streams that once fed the Great Salt Lake for use in homes, farms and industries.
As levels fluctuated this water year — between Oct. 1, 2023, and Sept. 30, 2024 — they ultimately fell short where one state official predicted it might hit amid snow melt.
The lake did still have high enough water levels to play home to a “tremendous number” of duck broods, more successful duck nests and more shorebirds this year, according to one state agency.
This spring, pelicans returned to Gunnison Island following a mass exodus the previous year amid low lake levels and — surprisingly — to Hat Island, where there hasn’t been a record of them nesting for decades.
Bird numbers in general also “do appear to have increased this year around the Great Salt Lake, mostly due to water being in the bays,” Faith Jolley, spokesperson for the Utah Divison of Wildlife Resources, said in an email.
Yet water levels are still below the 30-year average and a target level the state has defined as healthy.
A time-lapse of satellite images of the lake shows the Great Salt Lake pulling back over 30 years, turning Antelope Island into a peninsula and Farmington Bay into a dust pit.
(Interactive from Google Earth Engine) The above time-lapse shows changes to Utah’s Great Salt Lake between 1984 and 2022. Press play or select a year to see how the lake has shrunk over the past 32 years.
The Department of Natural Resources has developed an elevation matrix for the Great Salt Lake identifying its healthy range — when islands are islands again, salinity levels help brine shrimp and brine flies thrive, and bird habitat is abundant — but the water is not so high that it causes the flooding and havoc seen in the 1980s. That ideal level is between 4,198 and 4,205 feet above sea level.
The last time the lake reached an average annual elevation above 4,198 feet was 2002 — the same year Salt Lake City last hosted the Winter Games. The lake came close to the healthy range in 2012 but didn’t quite make it over 4,198.
The south arm of the lake had its best water year since 2020 and the north its best since 2021. Water levels averaged 4,193.4 in the south arm and 4,190.8 in the north arm.
As of Sept. 30, the end of the water year, the south half of the Great Salt Lake sits at 4,192.5 feet and the north half is at 4,191.8 feet.
For weeks early this summer, the south arm floated around 4,195, a level that Great Salt Lake Commissioner Brian Steed said is categorized as “some adverse impacts” to the animals and plants that depend on the lake.
But levels mostly dropped in the south arm starting in July, while the north arm stayed mostly the same. A rock-filled railroad causeway bisecting the lake restricts water from flowing north, which means the elevations in the two halves sometimes vary.
State resource managers filled in a breach through that causeway in 2022 to stave off rising salinity levels in the fresher southern half, which has made those elevation differences much more pronounced. They won’t raise the breach again unless the south arm of the lake drops to 4,190 feet.
With the causeway still open, the north arm has stayed mostly stable in recent weeks as the south arm has dropped amid high temperatures.
The causeway has likely kept the over-tapped lake viable for decades, allowing multimillion-dollar lake-based industries and massive flocks of migrating birds to thrive.
It also means the north and south arms of the lake have different salinity levels and are different colors.
Megan Banta is The Salt Lake Tribune’s data enterprise reporter, a philanthropically supported position. The Tribune retains control over all editorial decisions.
