Climatic controls on groundwater-surface water interactions within the Boreal Plains of Alberta: Field observations and numerical simulations

摘要

Hydrologic data were collected over eleven years at a catchment situated in low permeability glacial terrain within the Boreal Plains (Alberta, Canada) to evaluate the hydrologic interactions occurring between landscape units (i.e., shallow pond, extensive peatlands, aspen forested hillslopes). Two-dimensional numerical models were developed using a fully-integrated groundwater-surface water model to evaluate key landscape features that allow these ecosystems to persist within the sub-humid climate. Study results show that the dynamic interactions between the pond and peatlands are driven by precipitation and evapotranspiration. As a result, pond and peatland water levels reflect recent climatic trends. Limited hillslope contributions to the peatlands occur, indicating they are not required within this climatic setting for long-term maintenance. Instead, the peatlands conserve water within the landscape and supply it to adjacent landscape units. By contrast, the pond and the aspen forested hillslopes are dominated by high rates of evapotranspiration, and represent net water sinks within the landscape. Further simulations indicate these hydrologic systems are sensitive to pond and peatland evapotranspiration rates, and the hydraulic conductivity of the underlying glacial till substrate. (C) 2015 Elsevier B.V. All rights reserved.