Metro Vancouver has substantially finished construction on its award-winning, one-kilometre-long Second Narrows Water Supply Tunnel, one of five new regional water supply tunnels designed to ensure delivery of drinking water in the event of a major earthquake.
The tunnel lies 30 metres below the bottom of the Burrard Inlet, is 6.5 metres in diameter, and contains three new large-diameter steel water mains designed to withstand a one-in-10,000-year earthquake while delivering drinking water every day to Vancouver, Burnaby, Richmond, New Westminster, Delta, and parts of Coquitlam and Surrey.
“Building this tunnel under the Burrard Inlet was a massive project and is another great example of the critical infrastructure that Metro Vancouver delivers for this region,” announced Mike Hurley, Chair of Metro Vancouver’s Board of Directors, in a statement. “For a sense of scale, this tunnel was large enough to drive a truck through — and now it holds three separate water mains that will increase capacity and ensure we can continue supplying water following a major earthquake.”
The tunnel was excavated through a variety of ground conditions using a slurry tunnel boring machine, and replaces three water mains built between the 1940s and the 1970s that were vulnerable to damage during an earthquake and are nearing the end of their service lives.
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With the tunnel now substantially complete, Metro Vancouver will start connecting the new water mains to the existing water supply system. Work on these tie-ins will occur on both sides of the Burrard Inlet, and each connection is expected to take several months to complete.
In 2024, the project received the Tunnelling Association of Canada’s Canadian Project of the Year Award, which is presented to a team that has significantly contributed to a project in Canada that has demonstrated the “highest level of engineering skill. and shown insight and understanding of underground construction”. In 2025, the project was also presented with the Award of Excellence from the Association of Consulting Engineers — BC Chapter in the Municipal and Civil Infrastructure category.
The Second Narrows Water Supply Tunnel is expected to be fully in service by 2028.
