Groundwater conditions in the Grande Prairie-Beaverlodge area, Alberta

The Grande Prairie area is located in west-central Alberta between longitudes 118 degrees and 120 degrees west and latitudes 55 degrees and 55 degrees 40'' north. It covers approximately the southern two thirds of the Canadian National Topographic System map area 83M - Grande Prairie, Alberta.

Groundwater chemical information is divided into glacial drift or bedrock derived (the latter consisting of Upper Cretaceous Wapiti Formation and Smoky Group). The bedrock source is further subdivided into depth intervals of 0 to 150 ft (0 to 46 m), 150 to 300 ft (46 to 91 m), and 300 to 450 ft (91 to 137 m). The data did not warrant explicit investigation to greater depths.

Maps showing the distribution of total dissolved solids, calcium, magnesium, hardness, sodium, potassium, carbonate, bicarbonate, alkalinity, sulfate, chloride, and fluoride are presented for each of the four subdivisions. Maps presenting chemical equivalent as a percent of anions or cations are also presented for pertinent ions in all intervals.

Over most of the study area groundwater to a depth of 450 ft (137 m) is of fairly good quality. Total dissolved solids contents are generally less than 1500 mg/l. Groundwater is of the sodium bicarbonate type with a tendency to calcium bicarbonate type in areas of thick glacial drift. In the northeastern portion of the area groundwater is of poor quality due to the proximity of the Smoky Group shales. Groundwater in the glacial drift is expected to be of the calcium sulfate type with total dissolved solids concentrations greater than 2000 mg/l. Groundwater in the bedrock is of the sodium sulfate type and total dissolved solids contents are greater than 2000 mg/l.

Maps are presented showing distribution of hydraulic head for various depth intervals down to 600 ft (183 m). Horizontal components of groundwater flow are directed to the south and east. Vertical components of flow show a complicated pattern hypothesized to be related to the a nature of the Wapiti Formation.