Earth Sciences Report 1977-01

Earth Sciences Report 1977-01

ESR 1977-01

Hydrogeology of the Lesser Slave Lake Area, Alberta

Author(s) Vogwill, R.I.J. Date 1978-01-01

The hydrogeology of the Lesser Slave Lake area (NTS 83O) is described. Data are unevenly distributed and have been supplemented with field observations and a test drilling program during 1974. A large amount of interpretation was involved in the construction of the hydrogeological map and profiles.

The most important aquifers in the area are basal or near-basal sands and gravels occurring in preglacial drainage networks. They have been assigned a 20-year safe yield of 25 to 500 igpm (approximately 2 to 38 l/sec).

The most important bedrock aquifers are sandstones and coals of the Wapiti Formation which have been assigned a 20-year safe yield of 5 to 25 igpm (approximately 0.4 to 2 l/sec).

Water chemistry is variable and total dissolved solids contents range from 200 to 2000 ppm in the drift and non-marine strata. Iron concentrations are usually very high. Groundwaters are generally of the Ca or Na/HCO3 +C03 type with local areas of (1) Ca or Na/SO4 types attributed to high sulfate contents in till, and (2) Na+Ca/Cl types attributed to contamination from deeper marine strata. These deeper marine rocks contain highly saline waters of the Na/Cl type.

Vogwill, R.I.J. (1978): Hydrogeology of the Lesser Slave Lake area, Alberta; Alberta Research Council, ARC/AGS Earth Sciences Report 1977-01, 38 p.