Distribution of Total Dissolved Solids in the Spirit River Hydrostratigraphic Unit

This map depicts the distribution of total dissolved solids (TDS) in groundwater in the Spirit River hydrostratigraphic unit (HSU). The map is a result of an empirical Bayesian kriging technique using publicly available formation water chemistry data from oil and gas well drillstem tests and production fluids.

The distribution of 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 (predicted value minus measured value) plotted at each location to indicate where underprediction or overprediction occurs. Three additional inset maps show the results of the cumulative interference index analysis, the distribution of total dissolved solids (TDS) and the results of water driving force analysis, respectively. The geometry and variable thickness of the Spirit River HSU are illustrated on schematic cross-sections, and the relationship between geological units is further described in an accompanying regional lithostratigraphic and hydrostratigraphic table.