Evaluation of snow dynamics in a basin fen-bog complex in the Western Boreal Plains, Canada.

English Abstract:

In the Western Boreal Plains (WBP) region of Northern Alberta, snow represents ~25% of annual precipitation and is, therefore, a potential recharge water source for landforms (e.g. bogs, coarse textured hillslopes) during spring thaw. Influences on snow accumulation and redistribution during winter include canopy openness, tree-stem density and wind fetch. These are not consistent across landform/peatland types in the WBP, where contrasting tree density, size and species may influence accumulation, redistribution and ablation dynamics. Inclusion of snow dynamics is essential for understanding water availability in the sub-humid WBP climate. Few studies focus on snow dynamics in the WBP and distribution of over-winter precipitation stores across upland-peatland systems remains unclear. Snow distribution, ablation, radiative forcings, basin dynamics and controls are quantified for a poor fen-bog complex, situated in an elongated, sloped perimeter basin. Field measurements, taken March-May, 2012-2014, found snow depth lowest in the sparsely treed, open fen, and highest in the densely treed bog and at changes in slope, suggesting wind to be the dominant snow redistribution control. Increased tree density and height correlated with decreased ablation in the bog-complex. Canopy/stem density decreased wind speeds above the snow pack, making aeolian redistribution negligible. Beyond developing a better understanding of snow dynamics in natural basin-fen systems, it is also of particular relevance to landscape reclamation design, given basin features on post-mined landscapes are targeted as future wetlands.