ABSTRACT: GIS-based terrain analysis of linear infrastructure corridors in the Mackenzie River valley, NWT,

CGRG Bibliography of Canadian Geomorphology
Search Results

Author :

Date :

Title :

Publication :

Issue :

Page(s) :

Abstract

Continued climate warming, and associated progressive thaw of frozen ground will have potentially serious implications for the structural stability and performance reliability of linear infrastructures traversing permafrost terrain. Of particular current concern are the long-term viability of existing and proposed pipelines and the extensive networks of seasonal and all-weather roads in the Mackenzie River valley. Access to suitably-scaled information about current and future terrain conditions, both local and regional, is of critical importance to engineers, regulators, and decision-makers responsible for the development and maintenance of these networks. The Geological Survey of Canada is developing an ArcGIS-resident, multi-component terrain analysis methodology for evaluating permafrost terrain in terms of the probable geothermal and geomorphological responses to climate warming and/or antropogenic disturbance. A GIS-integrated finite-element transient ground thermal model (T-ONE) enables prediction of local-regional permafrost conditions (i.e. ground temperature, permafrost distribution and thickness, active layer development) and future responses of permafrost to climate warming. Analysis of topographic and topologic characteristics of terrain will clarify the influences of surface and channel hydrology on local erosion potentials. A Weights of Evidence-based landscape-process model, currently under development, will consider multiple terrain factors (e.g. geology, permafrost, topology and topography, surface hydrology) for identification and mapping of terrain with particular sensitivities and susceptibilities to various manifestations of terrain instability, including slope failure, subsidence, thermokarst, surface and bank erosion. This terrain analysis methodology is currently being applied to a 2 km buffer spanning the proposed Mackenzie Gas Pipeline right-of-way, and along winter and all-weather road networks in the Mackenzie River valley, NWT. Initial ground thermal modeling completed within the buffer area has identified thermally sensitive terrain for which permafrost will either completely disappear or warm significantly to near isothermal conditions within the next 25 to 55 years. Ongoing development and application of the broader integrated terrain analysis package will facilitate the prediction of specific terrain units and/or localized areas that are particularly susceptible to terrain instability during the next century. This information will be of considerable utility to responsible agencies and stakeholders concerned with the long-term viability economics and of pipelines and roads in the Mackenzie River valley.

Bibliography of Canadian Geomorphology