Earth Sciences Report 1971-02

Earth Sciences Report 1971-02

ESR 1971-02

Hydrogeology of the Grimshaw-Chinook Valley Area, Alberta

Author(s) Tokarsky, O. Date 1971-01-01

The hydrogeological map of the Grimshaw-Chinook Valley area is the prototype for a forthcoming hydrogeological reconnaissance map series, although it is constructed at a larger scale and covers a smaller area than will subsequent maps in the series. It presents on one map the most important hydrogeological aspects of the area: topography, geology, meteorology, groundwater probability, water levels, hydrochemistry, springs, major artificial works, etc.

The main aquifers in the area are near-surface gravels, herein termed the Grimshaw gravels, which are capable of yields in excess of 100 imperial gallons per minute (igpm); and sandstone lenses within the Upper Cretaceous Dunvegan Formation, the cumulative yield of which at any one point may range from 25 to 100 igpm. Water quality is generally good within the Grimshaw gravels, the total dissolved solids content averaging about 500 milligrams per litre (mg/l); and is variable within the Dunvegan Formation ranging from less than 500 mg/l in recharge areas to over 4000 mg/l in discharge areas. Other more locally used aquifers include sand and sand and gravel lenses within the drift. Sands and gravels at and near the base of a buried channel lying at depths of from 500 to 800 feet below ground level constitute a potential aquifer which has not yet been tested for yield.

Calculations of approximate rate of natural recharge to the groundwater reservoir indicate that this may amount to 1.2 to 1.9 inches per year or from 7.5 to 12% of the annual precipitation.

Tokarsky, O. (1971): Hydrogeology of the Grimshaw-Chinook Valley area, Alberta; Research Council of Alberta, RCA/AGS Earth Sciences Report 1971-02, 22 p.