Landscape susceptibility, hazard and risk assessments along pipeline corridors in Canada

This article discussed work that was carried out to inventory landslides and assess hazards along two proposed gas-pipeline routes in the North. Landslide inventories and hazard assessments are necessary to quantify and qualify the risk of environmental impacts from landslides on linear infrastructure. The Yukon Alaska Highway Pipeline and the Mackenzie Gas Project Pipeline, which will both be over 800 kilometres in length, will cross harsh landscapes characterized by permafrost terrain and will be at risk from geological hazards, including landslides with debris flows, earthquakes, subsidence, and permafrost degradation. The work involved inventorying and mapping landslides via aerial photography and field visits to identify the frequency-magnitude relationships for debris flow fans along the route and the creation of qualitative parametric landslide maps for both proposed pipeline corridors. A good correlation was found between actual landslide distribution and the landslide susceptibility maps. For the Mackenzie Valley Pipeline Corridor, most landslides have occurred in fine unconsolidated sediments and shallow slopes. Landslides in the Yukon Alaska Highway Corridor mostly happened in unconsolidated sediments, but a few took place in bedrock with high relief. The preliminary investigation revealed that a slope hazard exists in both corridors and must be taken into account during pipeline development. The results are intended to facilitate better decision-making for planning, constructing, and maintaining safe and economically viable pipeline routes in Northern Canada. The mapping methodology was outlined. 13 refs., 1 tab., 6 figs.