Distribution of Total Dissolved Solids in the McMurray Hydrostratigraphic Unit

This map depicts the distribution of total dissolved solids (TDS) in groundwater in the McMurray hydrostratigraphic unit (HSU). The map is a result of an empirical Bayesian kriging technique using publicly available water chemistry data from Alberta Environment and Parks' (AEP) Alberta Water Well Information Database (AWWID), compiled data from oil and gas operators in the oil sands area, and formation water chemistry data from oil and gas well drillstem tests and production fluids.

The TDS was mapped at a regional scale using many years of data, thus providing a good indication of regional water chemistry within the HSU rather than site specific values. The uncertainty of prediction is depicted on an inset map, which shows the residual values (modelled value minus measured value) plotted at each location to indicate where underprediction and overprediction occurs. Two additional inset maps show the distribution of hydraulic heads and the results of water driving force analysis, respectively. The geometry and variable thickness of the McMurray HSU are illustrated on schematic cross-sections.