This grid dataset is a rendering of the thickness and distribution of sediment overlying the bedrock topography in the Edmonton–Wabamun regional hydrostratigraphic investigation area. The thickness and distribution of sediments overlying the bedrock surface in the Edmonton–Wabamun area is highly varied, ranging from less than 1 m to as much as 114 m. These sediments include Neogene fluvial deposits, glaciogenic materials deposited during Quaternary glaciation, as well as postglacial sediments.
The grid was modelled using a 200 m grid cell spacing, and should not be used for local-scale studies requiring a higher spatial resolution.
33188 data points of varying quality and coverage were compiled for the construction of the Edmonton–Wabamun area bedrock topography. The most significant data source was the extensive collection of well records compiled in the AWWID. The AWWID has abundant, relatively low-quality data records, which include location inaccuracies resulting in numerous wells with duplicate locations. In cases of co-located data, water-well records were evaluated on cross-section to consider surrounding data and the accuracy of lithology information contained within the record. This was a manual process to identify the most correct duplicate well litholog to ensure the bedrock topography was delineated properly in real and synthetic data. Water well records that were not considered to be correct were maintained in a final database, but not used as input for the modelled surface.
The 33188 data points were used to model the Edmonton–Wabamun area bedrock topography. The Edmonton–Wabamun area sediment thickness grid was created by subtracting the Edmonton–Wabamun area bedrock topography from the AltaLIS digital elevation model (DEM; resampled to a 200 m grid cell size), which represents the present-day land surface.
All borehole and synthetic data were sampled to the AltaLIS 15 m provincial digital elevation model (DEM; resampled to 200 m grid cell resolution) to provide a borehole top elevation (m asl) to correlate lithological descriptions between boreholes and to create the bedrock topography grid. This process was necessary as the elevation of AWWID water wells, in many cases, was not available/recorded or verified, and if reported was estimated from a topographic map, field investigation or handheld Global Positional System (GPS) device. GPS devices have accuracies reported by the AWWID of ~1–30 m, but are of varying device quality and cannot be assessed for accuracy between devices. Elevation values of moderate- and high-quality data from AGS boreholes and fieldsites, geophysical logs, and previously published geological and hydrogeological maps were also checked with the DEM to verify elevation accuracy and modified to match the DEM, if necessary.
The vertical accuracy of the 12 m DEM is stated as 5 m @ 90% where derived from 1:60 000 aerial photographs using photogrammetric methods.
This gridded dataset was derived by subtracting the computer-generated geostatistical model of the Edmonton–Wabamun area bedrock topography from the DEM (sourced from Sustainable Resource Development; 12 m cell-size and resampled to a 200 m grid cell size), which represents the present-day land surface.
Data used to construct the Edmonton–Wabamun area bedrock topography were derived from a variety of low- to high-quality borehole data, including lithologs submitted by water well contractors and compiled in the Alberta Water Well Information Database (AWWID), downhole geophysical logs collected from water wells and coal surveys conducted by the Alberta Research Council, AGS borehole logs and field data; stratigraphic picks made from oil and gas geophysical logs by AGS geologists.
Cell Size: 200 m