The project to upgrade the main sewer line under Highway 99 connecting both sides of Mamquam Road has been delayed again due to new complications of installing the new pipe under the highway.
While the District and its contractor hoped to use a trenchless method to minimize traffic disruption, efforts to go this route have failed, District says. Project completion will now require a traditional trench dig across Highway 99 in coordination with the Ministry of Transportation and Infrastructure (MoTI).
The issue that has been discovered is that the asbestos cement pipe material on either side of the highway changes to steel for the section directly underneath the highway, and was not indicated in the District’s records that date from the 1970s. This prevents the ability to tunnel through with a “pipe burst” method and leaves one option – to trench across the highway.
“We have made every effort to replace this pipe without opening up Highway 99 as that has significant impacts we were hoping to avoid,” says Gary Buxton, General Manager of Community Planning & Sustainability. “Unfortunately, this can be likened to an old home renovation where you don’t fully know what you’re dealing with until you open up the walls. The drawings we had available to us are 50 years old with very little information, and our planning, unfortunately, didn’t pan out as expected.”
The project did progress to complete 50% of the sewer main replacement between Diamond Head Road and Highway 99.
District staff will bring a new project back to Council for funding in 2023 and will work with MoTI on project design and timing. Trenching across the highway is complex from a traffic management point of view and has always been the option of last resort.
