Active layer monitoring network in the Mackenzie Valley

Regions: Inuvialuit Settlement Region

Tags: physical sciences, active layer, permafrost, climate change, environmental change

Principal Investigator: Nixon, Mark (15)
Licence Number: 13025
Organization: Natural Resources Canada - Gelogical Survey
Licenced Year(s): 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990
Issued: Mar 28, 1999
Project Team: Fred Wright

Objective(s): One feature of permafrost that has responded significantly to past climate change is thickness of the active layer. The active layer, overlaying permafrost is earth material that thaws from the surface and refreezes each year. It forms the interface between permafrost and the atmosphere and biosphere including many human activities. Active layer thickness influences vegetation and soil conditions, thereby influencing hunting, gathering, forestry and agriculture. Thickness, texture, and moisture content of the active layer affects foundation conditions for transportation and construction. Changes in the active layer and thaw penetration can contribute to slope instability with impacts on transportation facilities and other structures. It is important to understand how the active layer varies locally and regionally and how it will respond to environmental change.

Project Description: This season we may visit areas between Tsighetchic and the coast in March and will survey from Fort Simpson to the Arctic coast in July. Inuvik Research Centre may take late season measurements as part of a cooperative program. Travel will be by road, small boat on the river and helicopter from Inuvik. Access to the sites is always on foot. This is the ninth annual survey of a network of thaw depth measuring devices (thaw tubes) and temperature data loggers along a transect extending from Fort Simpson to Tuktoyaktuk. The tubes consist of small diameter (2.5 cm or 1") water filler pipes anchored at 4 meter (12') depth and protruding about 20 cm (1') above the surface that record the maximum annual thaw depth at a site. Temperature dataloggers are installed in small screens above ground and buried just below the surface. Up to five 10 meter ground temperature cables will be installed this season in the upper valley to supplement the above instrumentation. A series of annual readings over a number of years will tell us if there is a change in thaw depth at that site and its relation to temperature conditions.