Examining the Water Use Efficiency of a Constructed Fen-Upland Watershed in Alberta, Canada.

English Abstract:

Oil sands development in the western boreal plains (WBP), northern Alberta, involves widespread surface mining, which disturbs natural ecosystems. More than 50% of the land cover impacted by oil sands leases are wetlands--the majority of which are fen peatlands. Recently, oil sands companies have focused on testing the concept of constructing peatlands into their post-extraction closure landscape. This research uses eddy covariance and climate monitoring systems to examine the fluxes of energy, H2O, and CO2 between a constructed fen-upland watershed and the atmosphere. The objective of this is to characterize the hydro-meteorologic functioning and initial trajectory of the constructed watershed relative to natural upland-fen systems over a two year (2013-2014) monitoring period following construction. Results from 2013 indicate that while evapotranspiration (ET) from the constructed fen was greater than ET from the upland, both fell below climate normals and ET measured from natural fen peatlands in the same region. In addition, both the constructed fen and upland were sources of CO2 in 2013; however, the constructed fen shifted to a small sink of CO2 in 2014, while increasing its ET by 50% relative to 2013. Precipitation and soil moisture were limiting factors in the constructed upland, which remained a source of CO2 in 2014 and experienced ET rates comparable to 2013. With vegetation growth, both the constructed fen and upland experienced an increase in their water use efficiency (WUE) over the two year study period.