A Hydrogeological Report of the Hobbema Indian Reserve

The Hobbema Reserve covers an area of about 115 square miles. The area lies within the Battle River drainage basin and the river itself forms part of the boundaries of the reserve.

The bedrock formations underlying the area and relevant to this report are the Horseshoe Canyon, Whitemud and Battle Formations of the Edmonton Group, and the Paskapoo Formation. The upper part of the Edmonton Group in the area is divisible into sandstone, shale and coal beds, and the Paskapoo comprises a series of shale, carbonaceous shale, coal, siltstone and sandstone beds. The sandstone beds of the Edmonton Group, ranging up to 40 feet thick, are the main source of groundwater supply with well yields possibly as high at 100 imperial gallons per minute. Well yields from coal seams and siltstone beds in the Paskapoo are estimated to be commonly less than 5 imperial gallons per minute.

Unconsolidated surficial deposits cover the bedrock. These deposits include preglacial(?) gravel 20 feet thick capping the bedrock for 15 square miles in the southeast part of the reserve.

These gravels do yield water but the capacity of water wells completed within them is unknown. Deposits of till occur above the gravel, with till and surficial sands being observed across much of the reserve. A major buried valley of the preglacial Red Deer River cuts across the area from the southwest to northeast.

The water is chemically mainly of the sodium bicarbonate type, with total dissolved solids commonly ranging from 700 to 1,000 parts per million. In the north part of the area, sodium chloride, though commonly a minor constituent is frequently present in significant proportions up to 40 per cent of the total ions. Groundwater supplies are commonly soft and suitable for human consumption.