TIMESCALES AND DRIVERS OF CHANGE AT THE BONNEVILLE SALT FLATS

Bonneville Salt Flats (BSF) is a vast and dynamic perennial salt pan in northwest Utah that is changing rapidly. The system responds to variations in temperature, rain, wind, evaporation, and groundwater flux, and also to a century of land-speed racing, potash mining, and recreation. The system is now changing in ways that are limiting these historic uses, and managers are responding with mitigation efforts to try to maintain multiple uses. Land managers and stakeholders are actively making decision about what to do to try to preserve this environment, primarily for the legacy of land speed racing, while still maintaining opportunities for natural resource extraction and ecosystem function. This work explores the natural variability in surface processes and environmental change at BSF and the drivers that influence the coupled groundwater - salt crust – social system over both human and geologic time scales. Field observations, geochemistry, and remote sensing analyses show how the surface has changed over seasonal, annual, decadal, and geologic time scales. Geochemical analysis of brines that both dissolve and grow the salt crust suggest that multiple different fluid populations are actively interacting with the ephemeral halite crust. Temporal and spatial changes in the salt crust extent, texture, and composition illustrate the ephemeral and dynamic nature of the BSF deposits. A data-driven understanding of the processes and time scales of change at BSF can help to guide sustainable management decisions that will preserve the character of this unique environment for generations to come.