Registered as a National Landmark, the Bonneville Salt Flats is a national treasure that has gained international significance as an awe-inspiring geologic phenomenon – a place so flat you can see the curvature of the planet.
For motorsports enthusiasts worldwide, of which there are millions, it is much more. It is hallowed ground. From the first speed record attempts in 1914 and through the present day, hundreds of records have been set and broken in a variety of automotive and motorcycle classes.
However, years of salt removal by an adjoining potash mining operation have damaged the Bonneville Salt Flats. Between 1963 and 1982, an estimated 11 million tons of salt was withdrawn. By the mid-1990s, the historic raceway had lost over 18 inches of salt crust.
Originally 96,000 acres in size, the Bonneville Salt Flats has been reduced to about 30,000 acres and those lands are threatened unless the salt removed to extract potash is then returned to the Bonneville Salt Flats.
There is a solution for continuing the mining operation and replenishing the Bonneville Salt Flats salt crust. From 1997 to 2002, under an agreement with the Bureau of Land management (BLM), the mine owner pumped brine water back onto the salt flats at an annual rate of 1.5 million tons of salt. The salt flats increased in thickness and hardness and the project significantly improved the aquifer which supports the salt crust volume.
The Save the Salt Foundation is seeking reinstatement of the 1997-2002 program, or an equivalent initiative.
The following are Foundation goals:
- Replenishment over an extended period of months so that the brine water can saturate the Bonneville Salt Flats;
- Replenishment with the same or more salt than is removed during the mining operation, with salt that is the same or better quality; and
- An agreement that no salt be removed from the Bonneville Salt Flats region.
History and Background
Description: The Bonneville Salt Flats is the densely-packed salt remnants of an ancient lake bed formed over thousands of years. Originally 96,000 acres in size, the unique geologic phenomenon in northwestern Utah has been reduced to about 30,000 acres as a direct consequence of an adjoining potash mining operation.
The State of Utah nominated the Bonneville Salt Flats for inclusion on the National Register of Historic Places in 1973. It was designated in 1975. Besides sodium chloride (table salt), the Bonneville Salt Flats is composed of potassium, magnesium, lithium, and other minerals. Water and wind shape the Bonneville Salt Flats throughout the year. A shallow layer of standing water floods the surface during the cooler months (November-May). The water slowly evaporates over the warmer spring and summer months while the wind acts to smooth the surface. The Bonneville Salt Flats is almost 5 feet thick near the center but only an inch or two at the outer edges.
Use: Beyond its irreplaceable beauty, the Bonneville Salt Flats possesses rare physical qualities that make it a destination for land speed racing, filmmaking and sightseers. The Bonneville Salt Flats has been used for racing since 1914 and countless land speed records have been set at the site. For example, the 300, 400, 500, and 600 mile per hour land speed barriers were broken on its natural straightway. The world-famous Speed Week dates back to 1949 and the Bonneville Salt Flats’s protected status recognizes the importance of racing as a compatible use.
Management: The Bonneville Salt Flats is managed by the U.S. Bureau of Land Management (BLM). Beyond its placement on the National Historic Registry, the BLM issued the Bonneville Salt Flats Recreation Area Management Plan (Plan) in 1985 and established criteria for managing the lands as the “Bonneville Salt Flats Special Recreation Management Area” (SRMA) and as the “Area of Critical Environmental Concern” (ACEC).
Potash Mining: Potash has been commercially produced since 1939 on federal lands leased by the BLM immediately south and east of the Bonneville Salt Flats. Mineral saturated water (brine) is collected from a shallow aquifer in about 100 miles of open ditches throughout the 88,000 acres of leased land.
A brine well also taps into a 1,000 foot deep aquifer for additional production. The collected brine is pumped into an 8,000 acre pond to evaporate water and capture potash. The solution is refined further in a series of smaller evaporation and harvest ponds, from which the potash is eventually separated from the salt in a mill. For decades, brine collection was a one-way system for salt removal from the Bonneville Salt Flats.
Between 1963 and 1982, an estimated 11 million tons of salt was withdrawn from the salt flats via the drainage ditch system south of Interstate 80 and along the raceway territory north of I-80. By the mid-1990s, the historic raceway had lost over 18 inches of salt crust.
According to hydrology and surface morphology studies commissioned by the BLM, the erosion was a direct result of the extraction of salt and other minerals through the groundwater mining operation, and a disruption of the hydrologic cycle which replenishes the salt crust.
Salt Laydown Project: There is a demonstrated process to replenish the Bonneville Salt Flats salt crust. In 1997, brine water was pumped back onto the salt flats by the mining contractor at the rate of 1.5 million tons of salt each year for 5 years. Over each winter, a high-quality brine (water and salt) left-over from the potash mining operation was pumped to the north side of I-80 and discharged onto the southern portion of the Bonneville Salt Flats.
The salt flats are covered with water from rain and snow for much of the year. The discharged brine dissolved and mixed in the transient pond and then spread across the salt basin. The pond evaporates during the hot summer months, allowing the pumped salt to become part of the crust. During the five-year program, the salt flats increased in thickness and hardness and the project significantly improved the aquifer which supports the salt crust volume.
A BLM commissioned study concluded that the laydown project “demonstrated that sodium chloride in brine removed from the Bonneville Salt Flats for mineral extraction can be replenished. …The laydown project helped maintain the ion mass balance in the shallow-brine aquifer associated with the Bonneville Salt Flats by replacing 4.2 million tons of salt estimated to have been removed during the five-year project, while providing a net addition of 2 million tons of salt to the shallow brine aquifer.”
Short-Term Solution Needs to be Permanent: The successful five-year laydown project came to an end. Although some replenishment continues, the duration is for a much shorter period of time. The brine water may not have time to percolate down to the underground reservoir and the quantity of salt returned to the Bonneville Salt Flats is less. Solution: a binding agreement on amount, quality and duration of a successful laydown project.
For more information, please visit the “Save the Salt Foundation” website at www.savethesalt.org