Some observations on permafrost distribution at a lake in the Mackenzie Delta, N.W.T., Canada

• Main Authors: Johnston, G. H., Brown, R. J. E.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 1964
• Subjects: permafrost; pergélisol; soils; sol; freeze thaw cycles; gel dégel; melting point; point de fusion; lakes; lac; drilling; forage; Canada; Inuvik; Mackenzie Delta; Arctic
• Online Access: https://nrc-publications.canada.ca/eng/view/ft/?id=7afc6b11-232a-4407-aeb3-7274eafaf25f; https://nrc-publications.canada.ca/eng/view/object/?id=7afc6b11-232a-4407-aeb3-7274eafaf25f; https://nrc-publications.canada.ca/fra/voir/objet/?id=7afc6b11-232a-4407-aeb3-7274eafaf25f

The thawing effect of bodies of water in contact with permafrost is a major concern in northern construction. Improper drainage or disrupted natural drainage which allows water to pond adjacent to buildings, roads or any structure results in increased thawing of the permafrost. The determination of the present disposition of the permafrost with respect to natural bodies of water would help to provide useful information for future engineering designs. The distribution of permafrost was determined adjacent to and underneath a lake in the Mackenzie Delta near the town of Inuvik N.W.T. The lake had an average diameter of about 900 ft. and a maximum water depth of 5 ft. At the center of the lake the sediments were unfrozen to bedrock, located at a depth of 230 ft. Permafrost occurred to a depth of 115 ft., 260 ft. and 196 ft. around the edge of the lake. These results were determined from borings carried out with a standard type diamond drill with a hydraulic feed. The frozen soil was sampled with a double-tube core barrel and in the center of the lake some undisturbed sampling was done using a piston-type sampler. Main conclusions are that the lake has caused the formation and maintenance of a deep thawed zone under the lake. The thawing effect is confined to the ground underlying the lake. Ground temperature measurements taken inland from the lake showed that the thermal influence of the lake extends for some distance beyond its perimeter. Les poches d'eau au contact du pergélisol au moment du dé gel constituent une nuisance importante pour la construction dans le Nord. Un mauvais drainage ou un drainage naturel interrompu qui permet à l'eau de s'accumuler à proximité des fondations d'un bâtiment, de routes ou de toutes autres structures entraîne le dégel du pergélisol. Le repérage du pergélisol existant par rapport aux poches d'eau naturelles permettrait de fournir des informations utiles aux travaux de génie civil. La répartition du pergélisol a été étudiée dans la région d'un lac du delta Mackenzie (à ...