Reducing the amount of water used to irrigate livestock feed crops may be critical to revitalizing the dried-out Great Salt Lake, a new study has found.
About 62 percent of the river water heading toward the lake in Utah ends up rerouted for human purposes, with agricultural needs responsible for almost three-quarters of those diversions, according to the study, published on Tuesday in Environmental Challenges.
The Great Salt Lake, which relies on mountain snowpack for much of its replenishment, is the biggest saline lake in the Western Hemisphere and the eighth largest on the planet, the study authors noted. The lake is also a biodiversity hotspot that houses critical habitats and sustains migratory birds, while also supporting area jobs and $2.5 billion in economic activity.
At the same time, however, the basin has lost more than 15 billion cubic yards of water over the past 30 years and is now getting shallower at a rate of 4 inches per year, the researchers explained. And as the lake has gotten smaller, area residents have increasingly endured respiratory problems from the fine particulate matter kicked up in the form of wind-carried dust.
“The lake is of tremendous ecological, economic, cultural and spiritual significance in the region and beyond,” said co-author William Ripple, a professor of ecology at Oregon State University, in a statement. “All of those values are in severe jeopardy because of the lake’s dramatic depletion over the last few decades."
About 80 percent of the diverted agricultural water ends up irrigating alfalfa and hay crops, according to Ripple.
With the goal of helping stabilize the lake and bolstering its restoration, Ripple and his colleagues proposed decreasing human water consumption in the area's watershed by 35 percent.
These conservation efforts would include a sizable reduction in irrigated alfalfa cultivation, fallowing of irrigated hay fields and taxpayer-funded incentives for farmers and ranchers who lose income as a result.
To draw their conclusions, the researchers employed data from the Utah Division of Water Resources to create a comprehensive water budget for the Great Salt Lake basin for 1989 through 2022. They found that on average, water flowing into the lake trailed behind consumption and evaporation by 500 million cubic yards per year.
Going forward, the authors suggested a range of conservation measures, including crop shifting, decreasing municipal and industrial use, and leasing water rights from irrigators. But they emphasized that farmers and ranchers who lose income should be compensated at a cost ranging from $29 to $124 per Utah resident per year.
“Revenues from growing both irrigated alfalfa and grass hay cattle feed in the Great Salt Lake basin account for less than 0.1% of Utah’s gross domestic product,” Ripple said. “But our potential solutions would mean lifestyle changes for as many as 20,000 farmers and ranchers in the basin.”
Yet although the necessary adjustments would be significant, Ripple stressed that they would not be insurmountable.
“With the right policies and public support, we can secure a sustainable future for the Great Salt Lake and set a precedent for addressing water scarcity globally," he added.