| The Paskapoo Formation overlies the uppermost coal seam of the Ardley coal zone of the Scollard Formation. Discontinuous deposits of Neogene gravel or Quaternary sediments unconformably overlie the Paskapoo Formation. The Paskapoo Formation comprises three units. The lowermost unit is correlative with sandstone of the Haynes Member (Haynes aquifer). Overlying the Haynes aquifer is a regionally extensive mudstone and siltstone-dominated unit correlative with the Lacombe Member (Lacombe aquitard). The uppermost unit is a sandstone-dominated unit, named the Sunchild aquifer. The complex and heterogeneous sedimentary geology of the Paskapoo Formation creates highly variable physical properties that govern the hydrogeology of the system. It appears that aquifers in the Paskapoo Formation are not continuous sand sheets with constant reservoir quality extending over large regions, but rather aquifer systems consisting of isolated fluvial channels and other types of sand bodies with limited spatial continuity. Fractures appear to be an essential control for the connections among the ""isolated sandstone aquifers"". There are also connections between Sunchild and Haynes aquifers where Lacombe aquitard is discontinuous or absent. The regional aquifer system is recharged by precipitations percolating along topographic highs, mostly located west. In a shallow system, Paskapoo Formation consists of groundwater flow toward the north-northeast. Local flow systems in sub-horizontal sandstones and shales probably occur with the well-fractured sandstones units acting as ""collectors"" for the downward moving groundwaters of overlying units. Groundwater flow through the permeable sandstones is rapid and emerges on hillsides and slopes as contact springs and in lower areas as soap holes, hummocky terrain, or muskeg. Groundwater that escapes these sandstone collectors continue downward into the regional system and discharge into the Athabasca River or Edson Lowlands. Groundwater quality is good. The Paskapoo Formation supports more groundwater wells than any other aquifer system in the Canadian Prairies. Located in a region of rapid population growth, this regional aquifer is under increasing pressure to provide water supply. |
Groundwater Information Network