REGIONAL-SCALE AQUIFER MAPPING IN CANADA
A common approach utilized in developing a national aquifer classification (e.g. United States, Ireland) is the use of geological mapping, and, organization into simple aquifer types. Five types are used in the US national principal aquifer map. A similar approach is applicable to organize regional aquifer mapping in Canada, based on key water-bearing openings: i) porous or inter-granular, ii) fractures, iii) karst. This scheme uses classes such as un-consolidated sand and gravel, sandstone, carbonate, carbonate-clastic and crystalline rocks. A limited set of aquifer types can be linked within hydrogeological settings (e.g. depositional environment/ landform; glaciofluvial/ esker) to permit rapid and simple characterization of hydrogeological conditions (e.g. water table or confined). Aquifer types can be linked to a hierarchical scale of geological maps and hydrogeological regions to facilitate a systematic assessment of groundwater resources in Canada.
Case studies in Ontario are presented defining the 3D distribution, geometry and architecture of individual aquifer settings, e.g. landforms; buried valleys, stratified moraines. Mapping in aquifer settings indicates that they may contain a number of aquifer sub-types, e.g. esker, fan and delta. Improved delineation of these aquifer types requires integration of archival field data organized within a stratigraphic database, and linked to a training framework of high-quality geophysical, sediment core and surface map data. The availability of sound conceptual models and seamless geological mapping will lead to improved 3-D geological modeling that will in turn help constrain the lack of data coverage and data quality encountered in regional hydrogeological mapping.