Bulletin 031

Author(s) Date 1974-12-31

The hydrogeology of Red Deer and vicinity was investigated from 1967 to 1969. The total area of study included 533 square miles, but test drilling and pump testing were limited to a 30 square mile area north of Red Deer. The field program comprised the drilling of 17 test holes totaling 7 906 feet, 33 bail tests, 3 long pump tests, the collection of 108 water samples, and the measurement of water levels nd water temperatures. Prior to this study, several sites for the development of groundwater supplies were selected by mapping natural phenomena related to groundwater conditions. This method is evaluated by comparison with results obtained from the present investigation. The hydrogeology was described, interpreted, and predicted by the application of regional study techniques. A two-dimensional, quantitative flow net, drawn for a representative hydrogeological cross section in the area, was used as a reference to guide interpretation of hydrogeological data and to calculate the natural yield of a portion of the main aquifer.

The regional hydrogeologic environment generates and controls various groundwater conditions which can be described by a group of parameters that collectively constitute the groundwater regime. The environment for the groundwater regime was described in terms of topography, geology, and climate. The topography is characterized by broad depression with gentle slopes, bordered on the east and west by uplands and incised at its lowest part by the valley of the Red Deer River which is the principal drainageway. The Tertiary and uaternary eposits are of particular interest in the study area. The Tertiary sediments consist of a sequence of alternating shales and sandstones of the Paskapoo Formation. Quaternary deposits include Saskatchewan Gravels and Sands in valleys on the bedrock surface and drift deposits of gravel, sand, silt, and clay. Climate is depicted by a mean annual precipitation ranging from 18 to 20 inches, a mean annual temperature of 53 degrees Fahrenheit, and a mean annual otential evapotranspiration of 20 to 22 inches.

Regime parameters described in detail are the occurrence, movement, and chemistry of groundwater. The main aquifers in the surficial deposits are sands and gravels. In the bedrock the principal aquifers are sandstones but shales also are important locally. Aquifer- erformance tests are used primarily to identify and evaluate aquifers suitable for the development of large groundwater supplies. Hydraulic conductivities of aquifers range from less than 1 to 1 000 gallons per day per square foot (gpd/square foot). Sixty five percent of the groundwater flow takes place in local and intermediate flow systems at depths up to 600 feet, and the remainder for the most part in high permeability sandstone layers at greater depths. Water quality is generally very good throughout the area and the dominant chemical type of groundwater is sodium bicarbonate. The total dissolved solids content of groundwater is usually less than 1 000 parts per million (ppm) but is as high as 8 000 ppm in small areas. Fluoride content is high in deep aquifers, ranging from 2 to 6 ppm. Groundwater temperatures to depths of 700 feet range from 5 to 10.8 degrees Celsius. Noncommercial quantities of natural gas are present in aquifers below 100 feet in the river valley and at greater depths in other areas.

The principal aquifer investigated during the study is a sandstone layer in the Paskapoo Formation found immediately north of the City of Red Deer. It has a known extent of about 60 square miles, occurs at depths ranging from 134 feet in the river valley to 600 feet in the highlands, ranges in thickness from 10 to 40 feet and in ydraulic conductivity from 186 to 565 gpd/square foot. The water quality in the aquifer is excellent except for a high fluoride content. Water temperatures range from 4.4 to 5.6 degrees Celsius. A atural yield of 2.3 million gallons per day was calculated for the aquifer by means of a flow net for a 2 by 11.5 mile area north of Red Deer. Of this quantity 900 000 gpd can be obtained in the river valley area from wells designed for capacities of 50 to 100 gallons er minute.

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Gabert, G.M. (1975): Hydrogeology of Red Deer and vicinity, Alberta; Alberta Research Council, ARC/AGS Bulletin 31, 104 p.