Cleaning up the Northern DEW Line

At the peak of the Cold War, the Distant Early Warning (DEW) Line was set up in Canada's North to provide early detection of any military approaches over Canada's northern border. Strung across the Arctic coastline from the Yukon to Baffin Island, the operation of the radar system littered the northern landscape with random waste dumps, redundant infrastructure, debris and contaminated soil.

By the 1990's, the radar defence shield was outdated and no longer in use, so the Canadian government launched a clean-up of the DEW Line to demolish and dispose of the surplus buildings and facilities, contaminated soil, hazardous materials, debris and landfills. This was a potentially difficult and expensive program due to the region's harsh weather conditions, remoteness and short summer season.

Defence Construction Canada, on behalf of the Department of National Defence, hired UMA as the prime consultant for this major environmental clean-up project. Working together with associate consultants The SGE Group Inc., and sub-consultants EBA Engineering Consultants Ltd., the team was challenged to find solutions that were environmentally sound and financially reasonable to deal with the contamination and waste at 21 DEW Line sites.

The environmental project, one of the largest in Canada, will remediate more than 100 existing landfills and dump sites, develop new landfills for the disposal of waste materials, demolish existing facilities, and remove contaminated soil and hazardous waste materials. The overall clean-up strategy aims to prevent the movement of chemical contaminants into the sensitive arctic ecosystem, and provides for the physical restoration of the sites.

To reduce costs and environmental risks and impacts on the project, UMA's team developed a unique design concept that uses permafrost (frozen ground) to contain leachate-producing landfills, as well as for the disposal of contaminated soils. An insulating layer of granular material is placed over the landfill to promote the formation of permafrost through the landfill contents, which mitigates leachate generation. Saturated permafrost acts as the primary containment barrier to minimize migration of contaminants into the surrounding environment.