Snow dynamics and water fluxes within a constructed watershed in Northern Alberta, Canada
Abstract
The most important aspect to consider during the development of reclamation soil covers and constructed watershed designs is the influence of the regional climate and the availability of water to recharge systems, which is driven by the difference between precipitation (P) and actual evapotranspiration (AET). Snowfall represents ~25% of P in the sub-humid climate of the Western Boreal Plains region of Canada (WBP) where, in most years, potential evapotranspiration (PET) slightly exceeds P. Despite the importance of water availability, few studies focus on the distribution of snow and, hence, the storage of winter precipitation in reclaimed oil sands landscapes in the WBP. In this study, the distribution, ablation and fate of snowmelt waters are quantified within a constructed ecosystem in a post-extraction oil sands environment in the WBP. Field measurements made during March/April 2013 indicated that snow depth was the greatest at changes in slope, which suggests that wind redistribution was a dominant control on snow distribution. Basin-averaged peak snow water equivalence (SWE) was 100 mm, but varied depending upon the presence (109 mm SWE) or absence (85 mm SWE) of vegetation. Over-winter accumulation of dust layers within the snowpack caused increased ablation rates when exposed at the melting surface, which decreased the snow surface albedo and subsequently increased the absorption of shortwave radiation. Similarly, vegetation presence and height (as influenced by time since reclamation/revegetation) also influenced ablation rates via increased absorption of shortwave radiation upon emergence of vegetation stems and branches from the snowpack. Recharge to aquifers within the constructed watershed was minimal, as the presence of ground frost constrained infiltration of snowmelt water. Accordingly, substantial surface runoff was observed from all reclaimed slopes, including those designed to reduce runoff and increase water storage, which indicates the importance of including snow dynamics when designing landscape-scale constructed ecosystems. This research represents one of the first studies on snow dynamics in constructed watershed systems in post-extraction oil sands landscapes. Understanding the distribution of winter precipitation and the availability of snowmelt waters to recharge constructed ecosystems is of great importance in a sub-humid climatic region where water availability is often limited.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.H43D1477K
- Keywords:
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- 1800 HYDROLOGY;
- 1863 HYDROLOGY Snow and ice;
- 1879 HYDROLOGY Watershed;
- 1890 HYDROLOGY Wetlands