ALBERTA’S PROVINCIAL GROUNDWATER INVENTORY PROGRAM: A MULTI-PHASE APPROACH TO GROUNDWATER MAPPING

To effectively evaluate the cumulative effects of groundwater development, geological and hydrogeological mapping programs are essential. Regulatory decisions are enhanced through improved groundwater characterization and support the establishment of indicators and thresholds to assess groundwater availability. In order to implement these scientifically-based decisions, the Alberta Geological Survey established the Provincial Groundwater Inventory Program to provide accessible groundwater information to various regulators throughout the province. This program involves a multi-phase approach whereby a hydrostratigraphic model is developed prior to the calibration of a numerical groundwater flow model. The first multi-layer hydrostratigraphic model has been constructed as a part of a regional scale groundwater study in the Sylvan Lake sub-basin, central Alberta.

Due to its location within the Western Canada Sedimentary Basin, the Sylvan Lake sub-basin derives significant groundwater resources from Paleogene-late Cretaceous near-surface bedrock units, as well as from overlying elongate-bodies of coarse-grained Quaternary-Neogene sediments located along buried valley systems. 2.5D grids were interpolated in RockWorks15 and SKUA to represent the major mappable hydrostratigraphic units in the Sylvan Lake sub-basin using data from continuous cores, down-borehole geophysical logs, airborne resistivity surveys, and water well lithologs. A full 3D model was created from these grids in RockWorks15 to describe the hydrostratigraphic architecture of the model domain and delineate the geometry of major aquifer and aquitard systems within the unconsolidated sediments and underlying bedrock strata. By providing a simplified understanding of the highly heterogeneous sediment and rock properties in the sub-basin, the groundwater flow modelling phase can be better informed as to the depositional elements, which affect fluid flow in the subsurface. This staggered and integrated approach to geological and hydrogeological mapping as a part of the Provincial Groundwater Inventory Program provides a tool for evaluating the impacts of groundwater development scenarios and aquifer sustainability in the Sylvan Lake sub-basin, and forms the foundation for regional land use planning in Alberta.