Simulations of fully coupled lake-groundwater exchange in a subhumid climate with an integrated hydrologic model

Abstract

A fully coupled, integrated surface water/groundwater model was used to study hydrologic controls on lake-groundwater interaction in the subhumid, Boreal Plains of northern Alberta, Canada. Findings from a previous water budget study indicate that lakes on the outwash landscape capture groundwater as a major source of water input and function as evaporation windows. Transient hydrologic responses of a flow-through style lake and outwash groundwater flow system were simulated for a three-dimensional model. Hydraulic heads, surface water depth, and the corresponding exchange fluxes between the surface and the subsurface were all simulated simultaneously and compared to field observations for the summers of 2002 and 2003. Replication of the transient flow regime required an anisotropy ratio of 10:1 for the outwash deposits and inclusion of riparian peatlands, which control lake-groundwater interaction and maintain surface water on permeable northern landscapes. Spatially and temporally variable evapotranspiration governed the water table configuration and lake-groundwater seepage patterns. Copyright 2007 by the American Geophysical Union.