Distribution of Total Dissolved Solids in the Scollard / Willow Creek Hydrostratigraphic Unit

This map depicts the distribution of total dissolved solids (TDS) in groundwater in the Scollard / Willow Creek hydrostratigraphic unit (HSU). The map is a result of an empirical Bayesian kriging technique using publicly available water chemistry data:

1. Alberta Environment and Parks' (AEP) Alberta Water Well Information Database (AWWID)
2. Alberta Health Services (AHS)
3. Alberta Energy Research Institute (AERI)
4. Baseline Water Well Test Database (BWWT)

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 or overprediction occurs. Due to the high density of data points, only residuals >1.5 and <-1.5 standard deviations are shown. Two additional inset maps show the distribution of hydraulic heads, and depth to and vertical thickness of the Scollard / Willow Creek HSU. The geometry and variable thickness of the Scollard / Willow Creek HSU are illustrated on schematic cross-sections, and the relationship between geological units is further described in an accompanying regional lithostratigraphic and hydrostratigraphic table.