Hydrogeological Characterization of the Upper Cretaceous–Quaternary units in the Fox Creek Area, West-Central Alberta

The hydrogeological characteristics and interaction with surface water are described for the area surrounding the Town of Fox Creek, Alberta. Hydrogeological mapping and water samples acquired as part of this study are used to develop a conceptual understanding of groundwater circulation. Key attributes of the geological framework were used to map regional hydraulic pathways. Groundwater recharge is expected to be enhanced in the area southwest of Fox Creek, compared to other parts of the study area. Similarly, groundwater movement in the bedrock will be aided by abundant sandstone in the uppermost part of the Paskapoo Formation southwest of Fox Creek. The potentiometric surface reflects ground surface topography with groundwater flowing from the benchlands in the southwestern margin of the study area and the Swan Hills, towards the north. The exception is the southeastern margin of the study area where groundwater flow is towards the Athabasca River. Concentrations of naturally occurring environmental tracers indicate that the rivers contain water with a mean age less than a decade. Analysis of downstream trends in river water sample results found that rivers only received an appreciable amount of baseflow where they were in close proximity to bedrock with high sandstone abundance. The rivers generally had decreasing baseflow as the underlying bedrock formations transitioned from the Paskapoo Formation to the Scollard and Wapiti formations to the north. The hydrogeological characteristics of this region are summarized by two conceptual hydrogeological landscapes that are based on topographic relief. Where sandstone is abundant in the subsurface, relief is high, resulting in deeper groundwater circulation and older baseflow sources to rivers. Relief is low in areas of less-resistant bedrock and surface sediments, which generally has lower hydraulic conductivity, thereby limiting groundwater recharge and resulting in more localized groundwater capture to rivers with younger baseflow sources.