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The Great Salt Lake has lost over 15 billion cubic yards of water in the last thirty years and is receding by about 4 inches every year. A review of its water management indicates that reducing irrigation is crucial for its preservation.
New research published today in Environmental Challenges reveals that 62% of the river water intended for the lake is currently diverted for human usage, with nearly 75% of that being attributed to agricultural practices.
Co-author William Ripple, a distinguished ecology professor at Oregon State University, emphasizes the major impact of water usage for livestock feed, stating, “The study underscores the concerning role of agricultural water consumption in the lake’s rapid decline,” noting that 80% of irrigation is directed towards crops like alfalfa and hay.
To help stabilize and start refilling the lake, the researchers suggest a 35% reduction in human water consumption within the Great Salt Lake watershed. This includes cutting back on alfalfa irrigation, allowing many irrigated grass hay fields to go fallow, and providing government compensation to farmers and ranchers who would experience loss of income.
Ripple remarked, “The lake holds immense ecological, economic, cultural, and spiritual importance for the region and beyond. All these aspects are at serious risk due to the lake’s significant decline over the past few decades,” as a member of OSU’s College of Forestry.
Using data from the Utah Division of Water Resources, the authors constructed a comprehensive water budget for the Great Salt Lake basin spanning 1989 to 2022. Over this period, the inflow of river water and precipitation to the lake was consistently outpaced by consumption and evaporation, resulting in an average loss of 500 million cubic yards per year.
The authors indicate that the water budget has faced a deficit for most of the last century, a situation that has worsened with ongoing climate change and drought conditions.
Ripple explained, “The unusually high snowmelt during the 1980s and 1990s temporarily masked the long-term decline in lake levels, with the lake reaching its peak in over a century back in 1987. However, since then, it has been declining at an average rate of about 4 inches per year.”
The Great Salt Lake, which has no outlet, is the largest saline lake in the Western Hemisphere and ranks as the eighth largest worldwide. Its vast drainage area of 21,000 square miles includes the Wasatch Mountains, which provide a significant portion of the basin’s water replenishment through snowfall.
As a hotspot for biodiversity, the lake is home to over 10 million migratory birds and supports 350 bird species. Decreasing lake levels pose a threat to essential habitats and could disrupt existing food webs, according to Ripple.
The lake supports approximately 9,000 jobs and contributes about $2.5 billion annually to the economy through recreational activities, mining, and harvesting brine shrimp. The lake is the leading supplier of brine shrimp eggs globally, a key resource for aquaculture; however, as the lake shrinks and salinity rises, the shrimp face physiological stress, leading to decreased production.
As the lake reduces in size, the risk to human health increases due to dust carried by the wind from the exposed saline lakebed, or playa. Scientists point out that 5% of the Great Salt Lake playa consists of fine particulate matter, which can infiltrate the lungs and cause various lung-related issues. The presence of hazardous heavy metals, remnants of past mining, smelting, and oil refining activities, compounds these concerns.
Depending on the conservation strategies implemented—such as changing crop types, reducing municipal and industrial water use, and leasing water rights—the authors estimate that compensating farmers and ranchers facing reduced income could range from $29 to $124 per Utah resident each year, considering the state’s population is around 3.4 million.
Ripple stated, “Profits from growing irrigated alfalfa and grass hay for cattle feed in the Great Salt Lake basin contribute less than 0.1% to Utah’s gross domestic product. However, our proposed solutions could lead to significant lifestyle changes for around 20,000 farmers and ranchers in the area.”
He added that the situation surrounding the Great Salt Lake reflects the socio-cultural transformation faced by many river basin communities throughout the West and worldwide as climate change is pushing many water budgets into a deficit.
“The economic and cultural adjustments required are considerable, yet achievable,” Ripple affirmed. “With supportive policies and public engagement, we can ensure a sustainable future for the Great Salt Lake and establish a model for tackling water scarcity on a global scale.”
Ripple collaborated with a multidisciplinary team of scientists from Northern Arizona University, Utah State University, and Virginia Tech, along with the Utah Agricultural Experiment Station and Sustainable Waters, a New Mexico-based nonprofit focused on global water education.
Funding for the research was provided by the National Science Foundation and the Utah Agricultural Experiment Station.
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