This dataset accompanies Open File Report 2009-02.
Between 1971 and 1983, the Alberta Research Council created a series of hydrogeological maps of Alberta. The geologists examined the sediment types present and used existing water well information to assign yield values to distinct zones within the mapped areas. They also looked at the materials, generally to a depth of 305 metres (1000 feet) below ground surface, and added the yields of the sediments encountered within this interval to arrive at a yield value for the whole.
Alberta Geological Survey compiled the shapefiles for the yield polygons, digitized by the Prairie Farm Rehabilitation Agency, and then digitized the remaining linework for the remaining map areas. Afterwards, we created a geodatabase of the yield polygons for the entire province and assigned yield values to the polygons based on the original maps. We also assigned the most likely formation name, age and lithology to the yield polygon.
This shapefile contains vector data. Data are contiguous, topologically correct polygons as built and enforced using ArcGIS software. We made no effort to ensure continuity of features with existing data in adjacent study areas (i.e., edgematching). In some cases, the original mappers attempted to ensure continuity of features between adjacent study areas.
During the compilation of the shapefile, Alberta Geological Survey (AGS) did not attempt additional edge matching. We found that all attributes have well-defined domains and were valid within the domains. Spot checks against the original maps were performed to check proper allocation of yield values to polygons. Georeferenced digital versions of the original hydrogeology maps were used as the basis for assigned polygon attributes. Yield polygons were assigned various colours depending on the assigned yield value. The colours for the same yield value varied between digital versions of hydrogeology maps, requiring careful consideration of the maps to properly assign yield values. The yield polygons are from two sources. The first is from digitization efforts completed by the Prairie Farm Rehabilitation Administration (PFRA) provided to AGS. AGS digitized polygons where PFRA did not digitize polygons or where the difference between the location of PFRA digitized polygons and the location of the lines on georeferenced versions of the hydrogeology maps was 100 m or more.