CONSTRAINING SPATIAL DISTRIBUTIONS OF SEDIMENTARY FEATURES THAT INFLUENCE PERMEABILITY IN THE BORDEN AQUIFER, ONT., CA

Prior studies have demonstrated that lithofacies exhibit distinct permeability modes. Thus characterizing the spatial distribution of lithologic packages can provide useful information to groundwater flow and transport models. A 30 meter horizontal core transect was collected, at lateral spacings ranging from 0.25-1.0 meter, in the well-studied sand aquifer at Canadian Forces Base Borden, Ontario, Canada. Mapping of the sediments in these cores provided data on the spatial distribution of the lithofacies and revealed features such as: channel-like structures, silt layers and dipping strata. The distributions of silt facies and the packages of medium sands, present in the channel-like structures, are of particular importance with respect to flow and transport because of the high permeability contrast compared to adjacent units. The 30 meter core transect has provided a detailed two dimensional view of the sedimentary features. In an attempt to gain a three dimensional view of these features additional cores were collected in much shorter transects parallel and perpendicular to a section of the main transect. The additional core transects provide important spatial and directional constraints on a relatively large silt lens and channel-like structures. The information provided by this study can be incorporated (through the addition of conditioning points) into groundwater flow and transport models.