The Bear River meanders almost 500 miles from its headwaters in Utah’s Uinta Mountains to its mouth at the Great Salt Lake, making it the longest river in North America which does not empty into an ocean. Instead, the Bear River serves as the main source of fresh water for the Great Salt Lake, a vast terminal lake in the Great Basin with no outlet except evaporation. This hasn’t always been the case, though. The Bear River once flowed north, serving as a tributary of the Snake River, and ultimately reached the Pacific Ocean via the Columbia River. That is until about 140,000 years ago when the earth erupted in present-day southeast Idaho and spilled lava across the Bear River’s path.
Now obstructed by expansive lava fields hardening into immense walls of basalt rock, the Bear dog-legged to the south and became—for the first time—a source of fresh water for the ancient inland sea that would eventually become the Great Salt Lake. The river was tenacious, though, and spent its time not only feeding fresh water to ancestors of the Great Salt Lake but also chiseling away at the basalt columns that obstructed its way toward the sea. The river was finally rewarded for its efforts millennia after having been cut off from the Snake and Columbia River Basins, and once again became a tributary of the Snake River. This fate would not last, however. Roughly 35,000 years ago, violent geology would have its way again. More lava flows around present-day Soda Springs, Idaho, bent the Bear River back toward the Great Basin where it still empties today.
And this has been a boon for the millions of residents—Homo sapiens and otherwise—of the Wasatch Front here in Utah. Let’s consider for a moment what life in central and northern Utah would be like if not for the Bear River. For starters, the Great Salt Lake would lose 60% of its annual inflow, drastically reducing its volume. I wonder if Brigham Young and his Saints would have even considered settling in the Salt Lake Valley after enduring the many lake-bed-dust storms courtesy of the Great Salt Lake that are becoming a growing concern today. We would certainly be deprived of the world-class migratory bird and wetland habitat supported by the Bear River at the famous Bear River Migratory Bird Refuge. Last fall, Ogden’s Standard Examiner newspaper reported that, quote, “the river had disappeared into a vast mudflat that used to be Bear River Bay.” Experts cited irrigation, municipal, and habitat uses in addition to a host of environmental and climate factors as causes of the Bear River becoming “tapped out” before it reached the Great Salt Lake. A snowpack that has doubled last year’s total according to the Salt Lake Tribune has the Bear River Basin’s snowpack brimming at nearly 300% its average this time of year. This promises to turn things around for the Bear River and the many species which depend upon it.
A complex and interdependent collection of variables impact the Bear River and its hydrologic fate—not least of which are humans, ecology, climate, and the occasional volcanic eruption.
I’m Josh Boling, and I’m Wild About Utah!
Bear River Diagram Courtesy Utah Division of Water Rights
Courtesy & Copyright Bryan Dixon
Courtesy & Copyright Josh Boling
Text: Josh Boling, 2019, Bridgerland Audubon Society
Sources & Additional Reading
Greene, Jack, The Bear River, Wild About Utah, May 24, 2018, https://wildaboututah.org/bear-river/
Beck, Russ, America’s Caveat River, Wild About Utah, Nov 16, 2016, https://wildaboututah.org/americas-caveat-river/
Hylland, Rebecca, What are Igneous, Sedimentary & Metamorphic Rocks?, Glad You Asked, Utah Geological Survey, https://geology.utah.gov/map-pub/survey-notes/glad-you-asked/igneous-sedimentary-metamorphic-rocks/