This grid represents the distribution of hydraulic head in the Swan Hills / Slave Point hydrostratigraphic unit (HSU). It is a result of a geostatistical model which was constructed using publicly available pressure data from drillstem test 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 describes the accuracy of the geostatistical layer used to create the final grid:
Mean error: -1.2 m
Root mean square error: 50.5 m
Mean standardized error: -0.012
Root mean square standardized:1.030
Average standard error: 43.6 m
The root mean square error of the final smoothed grid is 12.4 m
Number of samples:
See AGS DIG 2022-0050 for details on the horizontal accuracy of the input hydraulic head point data, which is affected by the locational accuracy of the wells.
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 3-cell rectangular neighbourhood. Smoothing the surface used the average cell value.
Step 1 (Modelling the surface): An empirical Bayesian kriging algorithm was used in the ArcMap Geostatistical Analyst extension to interpolate the hydraulic head values and create a grid of the head surface of the Swan Hills / Slave Point HSU.
Method report:
Method: Kriging
Type: Empirical Bayesian
Subset size: 100
Overlap factor: 1
Output surface Type: Prediction
Transformation: None
Neighborhood type: Standard circular
Maximum neighbours: 8
Minimum neighbours: 8
Sector type: 8 sectors
Angle: 0
Radius: 20250.32
Cell size: 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 3 by 3 cell neighbourhood was used. Smoothing the surface used the average cell value.
Step 3 (Grid Alterations): The final grid was clipped based on the extent of the Swan Hills / Slave Point HSU, and spatial distribution of hydraulic head data.