ABSTRACT: The relationship between aeolian processes and meteorological variables in the Seward Sand Hills, Saskatchewan, Canada.

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Abstract

Located within Palliser Triangle, the Seward Sand Hills is the easternmost major dune occurrence in southwestern Saskatchewan. The dune field is comprised of parabolic and blowout sand dunes. Though most of the dunes in the region are presently stabilized by sparse vegetation, active aeolian processes continue to rework the deposits into various forms of parabolic dunes and blowouts. The purpose of this study was to determine the relationship between geomorphic processes affecting parabolic and blowout dune morphologies and migration rates with respect to meteorological variables in the Seward Sand Hills of southwestern Saskatchewan. The collection of weather data and the measurement of erosion and deposition on three dunes was taken on a monthly basis over a twenty-month period. This provided more detailed information on the specific combination of factors and the temporal framework in which aeolian processes are at peak activity in the Seward Sand Hills. Late winter to early spring is the period of maximum aeolian activity in the Seward Sand Hills. All dunes experienced very little net forward migration, although, significant amounts of erosion and deposition were recorded during most months as a result of the constant migration of secondary bedforms within the active layer of the dunes. Analysis of potential sand transport showed that there was tremendous potential for sand transport in the Seward Sand Hills; however, this potential was rarely reached. During many months, dunes exhibited either no significant activity or activity only within the active layer without significant net forward migration. The results show that aeolian processes respond quickly to moderate variability in temperature, precipitation and wind regime, suggesting that sand dunes may act as good indicators of very short-term meteorological variability. Regression analysis showed that the monthly relationship between aeolian activity and weather is too complex to be adequately explained using Fryberger and Dean's ROSE method. Use of this method in the Seward Sand Hills is not accurate unless dune orientation coincides with the net overall resultant drift direction of the dune field. Immature dunes, blowouts, and dunes oriented in opposition to prevailing resultant drift directions cannot be adequately explained using Fryberger and Dean's method alone, as other variables such as vegetation, aspect and steering are just as critical in determining dune migration rates and drift direction.

Bibliography of Canadian Geomorphology