The Great Salt Lake (GSL) is the largest saltwater lake in the Western Hemisphere, a remnant of the vast prehistoric Lake Bonneville. As a terminal lake, water leaves primarily through evaporation, causing its surface area to naturally fluctuate with regional precipitation. However, the lake has been in a sustained decline for decades, dropping to a record low of 4,188.5 feet in November 2022. This severe water deficit has shrunk the lake’s volume by an estimated 50% from its historical average. The record low exposed significant portions of the lakebed, raising concerns about ecological stability and public health in the surrounding urban area.
Primary Drivers of Shrinkage
The primary reason for the Great Salt Lake’s decline is a long-term imbalance where water consumption exceeds natural inflow. Human activities diverting water from the Bear, Weber, and Jordan rivers—the lake’s main tributaries—account for an estimated 67% to 73% of the overall water level drop. This extensive upstream diversion reduces the volume available to replenish the lake.
Water use in the GSL watershed is heavily dominated by agriculture, which consumes nearly three-quarters of the diverted water. Approximately 80% of this agricultural water is used to irrigate alfalfa and hay crops grown as livestock feed. These water-intensive crops consume water that would otherwise flow downstream. The municipal and industrial sectors account for the remaining one-quarter of water use. Population growth in the Salt Lake Valley increases demand for residential and industrial water, contributing to a persistent and unsustainable water budget shortfall.
The other major driver is the changing climate, which intensifies water loss through increased evaporation. Warmer temperatures accelerate the rate at which water evaporates from the lake’s surface, contributing an additional 8% to 11% to the water level decline. This effect exacerbates the problem caused by human diversion, making it more difficult for the lake to recover even during wet years. Higher temperatures also impact the regional snowpack, which is the main source of the lake’s fresh water inflow. Earlier snowmelt and increased soil absorption reduce the amount of water reaching streams and rivers during spring runoff.
Ecological and Health Consequences
The exposure of large swaths of the lakebed presents a major public health hazard for the millions of people living downwind in the Wasatch Front. The exposed playa contains high concentrations of heavy metals, including arsenic, lead, copper, and mercury, which accumulated in the sediments over decades. When wind storms pick up this fine sediment, it becomes toxic dust that can be inhaled by the surrounding urban population.
This airborne dust has a high oxidative potential, which can cause cellular damage and respiratory issues upon inhalation. The potential for elevated rates of asthma, heart problems, and other chronic illnesses poses a serious concern for the region.
The receding water concentrates the remaining volume, causing salinity to spike beyond the tolerance levels of the lake’s unique ecosystem. For example, the South Arm reached 19% salinity in 2022, impairing the survival of brine shrimp and brine flies, which are adapted to a lower range (13% to 15%). The decline of these organisms threatens the entire food web supporting millions of migratory birds. Over 10 million birds, including up to 90% of the North American Eared Grebe population, rely on the lake as a stopover point along the Pacific Flyway, feeding heavily on the brine organisms for migration energy.
The economic consequences of the shrinkage extend to industries that depend on the lake’s resources. Mineral extraction and the brine shrimp harvesting industry generate an estimated $1.3 billion to $1.5 billion in annual economic output. The brine shrimp fishery supplies nearly 45% of the world’s brine shrimp eggs for the aquaculture industry. This industry faces increased operating costs for dredging harbors and reduced reproductive success due to high salinity.
Policy and Water Management Responses
State lawmakers have responded to the crisis by implementing significant policy changes aimed at restoring water flow to the Great Salt Lake. Over $1 billion has been appropriated by the Utah Legislature for water infrastructure and conservation efforts between 2022 and 2023. This funding targets broad improvements in water management throughout the watershed.
Water Rights Reform
A central legislative action focused on reforming water rights laws to incentivize conservation. New measures allow water rights holders, such as farmers, to lease or keep water in the lake without risking the forfeiture of their rights due to non-use. This change is intended to make it financially feasible for water users to dedicate conserved water to the lake.
Conservation Programs
The state has also heavily invested in agricultural optimization programs to improve on-farm water efficiency. These programs provide funding for farmers to upgrade to more efficient irrigation technologies, such as drip systems, and explore alternative, less water-intensive crops. Additionally, municipal conservation efforts, including restrictions on outdoor watering and the promotion of water-wise landscaping, have been enacted in the surrounding communities.
These efforts are coordinated through the development of a Great Salt Lake Basin Integrated Plan. This plan aims to provide a comprehensive strategy for balancing human water needs with the lake’s ecological requirements. The overall goal is to implement a combination of policy and infrastructure changes that permanently reduce the amount of water diverted from the lake’s tributaries.