Active Layer Monitoring Network in the Mackenzie Valley

Regions: Inuvialuit Settlement Region, Sahtu Settlement Area

Tags: physical sciences, active layer, permafrost, soil, climate change, environmental change, seasonal variation

Principal Investigator: Nixon, Mark (15)
Licence Number: 13169
Organization: Geological Survey of Canada
Licensed Year(s): 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990
Issued: Mar 15, 2001
Project Team: Scott Dallimore

Objective(s): One feature of permafrost that has responded significantly to past climate change is thickness of the active layer. The active layer, overlying 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, including but not restricted to climate change.

Project Description: This season, a party of two will survey tubes between Tsiigehtchic and the coast during March and April and from Fort Simpson to the Arctic Coast in July and August. Staff of the Inuvik Research Centre may take late season measurements north and south of Inuvik 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 year is the seventh 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 consists of small diameter (2.5 cm) water filled pipes anchored at 4 meter depth and protruding about 30 cm above the surface that record the maximum annual thaw depth at a site. Temperature loggers are installed in small screens and buried just below the surface. In the spring, water sampling in a few lakes will be continued. 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 thermal conditions.