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Process step
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Sources
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| The datasets were extracted from all projects constituting this series. |
| Groundwater mapping projects. |
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| The aquifer was defined as confined except where the Milk River Aquifer outcrops / subcrops. In this area, the confinement conditions have been defined using the following rules:
• Unconfined aquifer:Absence of clay and/or silt OR Till thickness is below 3 m
• Semi-Confined aquifer: Till and/or clay and/or silt thickness is below 5 m
• Confined aquifer: Clay and/or silt thickness is equal or above 5 m |
| Colton, R.B., Lemke, R.W., and Lindvall, R.M., 1961. Glacial map of Montana east of the Rocky Mountains. U.S. Geological Survey, Miscellaneous Geologic Investigations Map I-327, http://ngmdb.usgs.gov/Prodesc/proddesc_1391.htm Precise date temporal extent is unknown; however the starting date is before 1961. |
| Fenton, M.M., Walters, E.J., Pawley, S.M., Atkinson, N., Utting, D.J., Mckay, K., 2013. Surficial Geology of Alberta: Ungeneralized Ditial Mosaic. Energy Resources Conservation Board, Alberta Geological Survey, DIG 2013-0001, http://www.ags.gov.ab.ca/publications Precise date temporal extent is unknown; however the starting date is before 2013. |
| Okulitch AV, Lopez DA, Jerzykiewicz T., 1996. Bedrock geology, Lethbridge, Alberta-Saskatchewan-Montana. Precise date temporal extent is unknown; however the starting date is before 1996. |
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| The aquifer was defined as confined except where the Milk River Aquifer outcrops / subcrops. In this area, the confinement conditions have been defined using the following rules:
• Unconfined aquifer:Absence of clay and/or silt OR Till thickness is below 3 m
• Semi-Confined aquifer: Till and/or clay and/or silt thickness is below 5 m
• Confined aquifer: Clay and/or silt thickness is equal or above 5 m |
| Saskatchewan Energy and Ressources, 2015. Surficial Geology of Saskatchewan. http://www.infomaps.gov.sk.ca/website/sir_geological_atlas/viewer.htm Precise date temporal extent is unknown; however the starting date is before 2015. |
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| To define the Quadra Sand Aquifer confinement, four hydrogeological unit's thickness raster were used: Capilano-Salish, Capilano, Vashon Coarse and Vashon Till ones. These units were used since they overly the Quadra Sand Aquifer. For each raster, the cell values were converted to an integer by truncation, using ""Int"" tool. Two fields were then added to the attribute table: ""Confi"" and ""Confinement"". The first field ""Confi"" designates the aquifer conditions: 1 for free aquifer condition; 2 for semi-confined conditions and 3 for confined conditions. Each condition is described below:
• Free aquifer: gravel or/and sand; till with thickness < 3 m;
• Semi-confined aquifer: till with thickness > 3 m; clay or/and silt with thickness < 5 m;
• Confined aquifer: clay or/and silt with thickness ≥ 5 m.
In the second field, ""Confinement"", the ""Confi"" value was multiplied by a weight defined on aquifer conditions: 1 for free aquifer condition; 5 for semi-confined aquifer and 10 for confined conditions. The ""lookup"" tool was then used to create a new raster by looking up values found in the confinement field in the table of the input raster. The ""lookup"" field was the confinement. The resulting raster had two fields: count and value, which designates the confinement value. The value field was then reclassified (using the reclassify tool), thus the NoData pixels were assigned a new value of ""0"". This procedure was applied for the four hydrogeological units. These latter were then summed, using the tool ""Raster Calculator"". The resulting raster exhibits the summed confinement of the four hydrogeological units (field Value). A field ""Confinement"" is created and the values are classified as follow:
- Confined: value ≥ 30
- Semi-confined: value ˃ 10 et ˂ 30
- Unconfined: value ≤ 10 |
| Benoit, N. and Paradis, D., 2015. Three dimensional groundwater flow model of the Nanoose-Deep Bay area, Nanaimo Lowland, British Columbia; Geological Survey of Canada, Open File 7845, 1 zip file. doi: 10.4095/297046 |
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