Wind Erosion Potential of Lacustrine and Alluvial Soils Before and After Disturbance in the Eastern Great Basin, USA: Estimating Threshold Friction Velocity Using Easier-to-Measure Soil Properties

Abstract:

Disturbance of lacustrine and alluvial soils could increase aeolian dust emissions in the eastern Great Basin, but little is known about the susceptibility of these land surfaces to wind erosion. Threshold friction velocity (u_*t ), a necessary parameter to estimate wind erosion potential, is difficult to accurately measure; methods to estimate u_*t from alternate measurements would be useful. We measured u_*t and sediment production rate with a portable wind tunnel, and quantified relationships between u_*t and eleven easier-to-measure soil surface properties for both undisturbed and disturbed lacustrine and alluvial soils in Snake Valley, Utah. Soil surface type and disturbance significantly influenced u_*t, sediment production rate, and the relationships between u_*t and easier-to-measure soil surface properties. Only soils with surficial rock fragments and weak physical crusts reached u_*t before disturbance, whereas all surface types reached u_*t following disturbance. Soils with weak physical crusts had the lowest average u_*t and highest average sediment production rate before and after disturbance. Surprisingly, however, disturbance reduced sediment production rate. Soils with weak physical crusts and surficial rock cover are likely the most susceptible to wind erosion and subsequent dust generation both before and after disturbance. Silt concentration and penetrometer resistance were significant predictors of u_*t in undisturbed soils with weak physical crusts and surficial rock cover. Following disturbance, clay concentration and aggregate stability were significant predictors for soils with hard salt crusts and surficial rock cover. Prediction of u_*t using alternate measurements is promising, but measurement uncertainty must be considered.