featured work

Winter Road Portage Mapping
Winter Road Portage Mapping

  • Task: Produce georeferenced orthomosaic imagery and digital surface models of 42 overland portages spanning 170km of winter road alignment. Portages are broken up by large bodies of water. The furthest portage is a 185 km ferry distance each way from Yellowknife.

Methodology:

  • Step 1: Construct, place and survey over 50 ground control points during winter road season.

  • Step 2: In summer, perform photogrammetric aerial mapping using an RGB camera sensor. Map this remote area by use of a local Dehavilland Beaver DHC2 floatplane, collecting data at 8 cm resolution.

  • Step 3: Process aerial mapping data to centimeter level geolocation accuracy in X, Y & Z axes. Generate orthomosaic images, surface models and point clouds of each portage.

Application:

In March 2019, the winter road experienced temporary closure due to portage deterioration. Climate change modelling predicts increased frequency and intensity of warming in March of each year. The aerial mapping data produced for this project was used by winter road engineers in a first of its kind assessments of portage vulnerability.

High resolution orthomosaic imagery was used to characterize portage resiliency to premature melting based on substrate type (e.g. gravel vs natural ground). The digital surface models were used to characterize solar radiation exposure based on factors such as indecent solar angle and shadowing from surrounding natural vegetation.

With this information, engineers were able to assign vulnerability rankings based on substrate type and solar analyses. This innovative project approach allowed them to identify key target areas for increased portage resiliency (e.g. suggested locations for adding lifts of granular material).

For more information on this and many other winter road engineering projects unique to Canada’s north, visit Associated Engineering – Ice Engineering

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