Construction starts on Second Narrows Water Supply TunnelConstruction starts on Second Narrows Water Supply Tunnel<div class="ExternalClassEDF561A9805C4B24B6A6C9EB2DCB63D3"><p>​Metro Vancouver has started construction on the Second Narrows Water Supply Tunnel, a 1.1 km-long tunnel deep under Burrard Inlet between the District of North Vancouver and the City of Burnaby.</p><p>The project, slated to be completed in 2024, is one of five new regional water supply tunnels designed to boost water delivery capacity and strengthen the water system’s ability to withstand a major earthquake. The new tunnels will replace the existing water main crossings built between the 1940s and 1970s that were constructed primarily in excavated trenches on the bottom of the inlet.</p><p>The 6.5-metre-diameter Second Narrows tunnel will be excavated deep underground using a tunnel boring machine. Vertical shafts will be excavated 60 metres deep on the north side and 110 metres deep on the south side. </p><p>Three steel water mains will be installed inside the excavated shafts and tunnel, two of them approximately 2.4 m in diameter and the third 1.5 m in diameter. Once these water mains are installed, they will be connected to new valve chambers at each shaft site, and into the region’s drinking water system.</p><p>When complete, the tunnel will provide a seismically resilient crossing, and will increase the capacity of the existing system to meet the long-term needs of the growing population. </p></div>http://www.metrovancouver.org/metroupdate/PublishingImages/issue51-snwst.jpg2019-03-28T07:00:00ZGP0|#fa10f1b3-b2b5-4771-aabf-d0c9cee82ee2;L0|#0fa10f1b3-b2b5-4771-aabf-d0c9cee82ee2|Issue 51;GTSet|#d14ffe11-45dc-48fb-8684-ff109cf15a74<div class="ExternalClassA23B7E009F0C498EB8C9A98F0C489644"><p>​Metro Vancouver has started construction on the Second Narrows Water Supply Tunnel, a 1.1 km-long tunnel deep under Burrard Inlet between the District of North Vancouver and the City of Burnaby.</p></div>0