AECOM has been selected to provide engineering services for a new underwater potable water supply line in Yellowknife, now that the 1969 steel pipeline has begun to leak and reach its end of life.
The new 8.5-kilometre pipeline will be cement-mortar lined and polyurethane coated for protection against corrosion and abrasion. It will mean that Yellowknife can avoid drawing water from the region of a nearby and toxic former gold mine. Instead, drinking water will travel through the pipeline from the Yellowknife River across Yellowknife Bay.
The project will also involve upgrades to two pumphouse facilities at either end of the pipeline.
“As the City of Yellowknife’s singular water supply, we’re honoured to provide care, criticality, and risk consideration to this vital project, which will help protect the community against the effects of climate change,” announced Ian Dyck, senior vice president of AECOM’s Canadian water business.
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An AECOM water source selection study from 2017 said the replacement pipeline will safeguard the community’s drinking water, increase capacity for flood water retention, better secure essential services from the effects of flooding, and help reduce greenhouse gas emissions linked to water line replacement and system operations.
The study concluded that while the Yellowknife River source with a new submarine pipeline has a higher capital cost, it has less risk of arsenic contamination.
Prior to 1968, Yellowknife obtained its drinking water from the bay that is connected to Great Slave Lake. In 1969, the city switched its water source to the Yellowknife River over concerns about arsenic contamination from the Giant and Con mines. Using the bay remained an option, but required a special treatment process for arsenic removal in case levels increased.
In 2019, the federal government announced $25.8 million from its Disaster Mitigation and Adaptation Fund towards the replacement of the water pipeline. However, Yellowknife officials have needed time to secure an additional $9 million share for the project.
AECOM says they have worked closely with Yellowknife for nearly 50 years and have a permanent office there. In addition to the design, AECOM’s scope includes the completion of a detailed cost estimate, construction contract administration, environmental services, permitting, stakeholder engagement, and support navigating regulatory processes at all government levels.