Vancouver Fraser Port Authority gets approval to dredge Second Narrows
Work will begin in September to clear 25,000 cubic metres of material, allowing larger oil tankers to fully load. The project includes environmental monitoring.
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The Vancouver Fraser Port Authority has received federal approval to dredge 25,000 cubic metres of material from the Second Narrows, clearing the way for larger shipments of oil and increasing overall port capacity.
Currently, Aframax tankers calling at Trans Mountain's Westridge Marine Terminal in Burnaby can only fill to about 75 per cent capacity. A fully laden ship's draft wouldn't have enough keel clearance to meet international navigation standards. Starting in September, when the fisheries window opens, contractors will use a scow-mounted crane with a clamshell dredge to scoop up 25 to 30 barge loads of material and ship it off for disposal at a licensed facility.
The areas to be dredged run along the margins of the existing channel covering a surface area of about 17,000 square metres. In most areas, the dredges will remove 1.5 to two metres of material, although in some spots, it may be as much as six metres. The project also includes the removal of old decommissioned Metro Vancouver water mains from the floor of the inlet and the installation of two new navigational lights.
"Channels like this are heavily regulated, obviously," said Charlotte Olson, the port's director of infrastructure delivery. "We've received federal approval and our permits have over 150 conditions that we must comply with." The Canadian Impact Assessment Agency granted a permit after determining the project "is not likely to cause significant adverse environmental effects."
Dredging projects have the potential to churn up toxins settled on the seabed and cause turbidity problems in the water, but the conditions of the Second Narrows make that less likely. "You can imagine, the currents in this area are really quite strong, and so it's quite coarse sands, gravel, and cobbles, and there's not a lot of fine material," Olson said. As the work is carried out, a dedicated environmental monitor will check water quality and marine mammal impacts.
The federal permits come with requirements for habitat restoration projects to offset changes to the natural environment. Olson said details haven't been finalized yet, but it will likely involve planting new kelp beds. Costs for the dredging won't be known until the port finishes its procurement process, but the port will pay from its own revenues and some contribution from Trans Mountain.
