Researchers argue for a 35% reduction in human water consumption in the Great Salt Lake watershed, emphasizing the urgent need to cut irrigation for livestock feed to halt the lake’s rapid depletion.
Over the past three decades, the Great Salt Lake has lost more than 15 billion cubic yards of water, becoming shallower at a rate of four inches annually. A recent analysis suggests that reducing irrigation is essential to reversing this trend and preserving the lake.
Published today in the journal Environmental Challenges, the study reveals that 62% of the river water destined for the lake is diverted for human use, with agricultural activities accounting for nearly three-quarters of this consumption.
“The research highlights the alarming role of water consumption for feeding livestock in driving the lake’s rapid depletion,” co-author William Ripple, a distinguished professor of ecology at Oregon State University, said in a news release.
He notes that 80% of agricultural water use in the region is for irrigating alfalfa and hay crops.
To stabilize the Great Salt Lake and begin replenishing it, the authors propose cutting human water consumption in the watershed by 35%. This includes substantial reductions in irrigated alfalfa production, fallowing large portions of the region’s irrigated grass hay fields and providing taxpayer-funded compensation for farmers and ranchers impacted by these changes.
“The lake is of tremendous ecological, economic, cultural and spiritual significance in the region and beyond,” Ripple added. “All of those values are in severe jeopardy because of the lake’s dramatic depletion over the last few decades.”
The researchers compiled data from the Utah Division of Water Resources, creating a comprehensive water budget for the Great Salt Lake basin covering the years 1989 through 2022.
The study found that during this period, water inputs from river inflows and precipitation consistently lagged behind consumption and evaporation by approximately 500 million cubic yards per year.
Climate change and persistent drought have exacerbated the situation, intensifying the water deficit that has persisted for much of the past century.
“Abnormally large snowmelt inflow during the 1980s and 1990s served to temporarily obscure the long-term decline in lake levels, and the lake actually reached its highest level in more than a century in 1987,” added Ripple. “But it has been dropping by roughly 4 inches per year on average since then.”
The Great Salt Lake, the largest saline lake in the Western Hemisphere and the eighth largest globally, spans a 21,000-square-mile drainage basin that includes the Wasatch Mountains. Snowfall from these mountains is a crucial water source for the basin.
Hosting a rich biodiversity, the lake supports over 10 million migratory birds and 350 bird species. Its declining levels threaten essential habitats and disrupt food webs.
Additionally, the lake directly contributes to 9,000 jobs and fuels $2.5 billion annually in recreational, mining and brine shrimp harvesting activities. The lake is the world’s largest supplier of brine shrimp eggs, vital for global aquaculture. Shrinking lake levels and increasing salinity stress the shrimp, jeopardizing their reproduction.
Human health risks are also a concern. The shrinking lake exposes its saline bed, releasing fine particulate matter that can cause respiratory issues. The dust also contains toxic heavy metals from the region’s history of mining, smelting and oil refining.
The authors suggest various conservation strategies, including crop shifting, reducing municipal and industrial water use and leasing water rights from irrigators. Compensation costs for farmers and ranchers could range from $29 to $124 per Utah resident annually, given the state’s population of 3.4 million.
“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 added. “But our potential solutions would mean lifestyle changes for as many as 20,000 farmers and ranchers in the basin.”
Ripple highlighted that the socio-cultural changes facing the Great Salt Lake area mirror challenges in river basin communities globally, where climate change is leading to water scarcity.
“The economic and cultural adjustments required are significant but not insurmountable,” Ripple added. “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.”