This grid represents the distribution of hydraulic head in the Exshaw–Banff hydrostratigraphic unit (HSU). It is a result of a geostatistical model which was constructed using publicly available pressure data from drillstem tests (DST) from oil and gas wells.
The hydraulic head surface was mapped at a regional scale using many years of data, thus providing a good indication of regional groundwater flow within the unit rather than site-specific values.
The following statistics describe the accuracy of the geostatistical layer used to create the final grid.
Mean error =-1.0 m
Root mean square error = 39.9 m
Mean standardized error = -0.008
Root mean square standardized = 0.949
Average standard error = 37.8 m
The root mean square error of the final smoothed grid is 15.1 m
Selection criteria and the final data set used for interpolation of this grid are documented in the metadata for AGS DIG 2023-0027.
Step 1 (Modelling the surface): An empirical Bayesian kriging algorithm was used in the ArcMap 10.8.1 Geostatistical Analyst extension to interpolate the hydraulic head values and create a grid of the head surface of the Exshaw–Banff HSU.
Method Report:
Output surface type: Prediction
Transformation: None
Neighbourhood type: Standard circular
Maximum neighbours: 15
Minimum neighbours: 10
Sector type: 4 sectors
Samples: 322
Cell size: 500 m by 500 m
Step 2 (Grid Smoothing): The grid was smoothed using focal statistics which calculates for each input cell location a statistic of the values within a specified neighbourhood around it, in this case a 2-cell radius. Smoothing the surface used the average cell value.
Step 3 (Grid Alterations): The final grid was clipped based on the extent of the Exshaw–Banff HSU, and spatial distribution of data.