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Study supports Tsleil-Waututh Nation's concerns about increased marine traffic in Burrard Inlet

New research has reaffirmed what Tsleil-Waututh Nation has been saying for years – that marine vessel traffic is having a significant impact on overall wave energy in Burrard Inlet.
Tugboat from Lion's Gate Bridge
The wave-monitoring study found that vessel wakes significantly increase the overall wave energy in Burrard Inlet beyond natural wind-generated waves between 1.2 and 4.6 times depending on the location.

For Tsleil-Waututh Nation Elders and members, it’s obvious what increased marine vessel traffic in Burrard Inlet has done to their waters and lands.

Charlene Aleck, spokesperson for TWN’s Sacred Trust, says members have watched for years as erosion on the foreshore has coincided with more marine traffic, compromising important cultural places, damaging archaeological sites, and degrading key shorelines and beaches.

“Seeing the erosion happen before your eyes – it’s a piece of your history – it’s like having your grandmother's quilt and watching threads of it being pulled and torn,” she said.

Now, new research released in February has reaffirmed what the nation has been saying for decades – that marine vessel traffic is having a significant impact on overall wave energy in the inlet. And, it’s only going to get worse once the Trans-Mountain Pipeline expansion is operational.

The nation retained subject-matter experts Kerr-Wood Leidal and MarineLabs to conduct a study of the wave climate in the Central Harbour of Burrard Inlet, in front of the nation’s main community and at Whey-ah-wichen, an ancestral village site in Cates Park in North Vancouver.

The study, from August 2019 to September 2020, included the assessment of waves generated by wind and passing vessels using wave measurement buoys, data analysis, and reporting.

Vessel wakes significantly increase overall wave energy in Burrard Inlet

The study found that vessel wakes significantly increase the overall wave energy in Burrard Inlet beyond natural wind-generated waves between 1.2 and 4.6 times depending on the location, and that current tugboat traffic contributes up to 20 per cent of waves generated by vessels.

“The report clearly supports what Tsleil-Waututh Nation has been saying for decades, which is that boats significantly increase overall wave energy in Burrard Inlet, which in turn impacts shorelines and causes erosion,” said Spencer Taft, the nation’s cumulative effects project manager.

“It uses Western science to support Tsleil-Waututh knowledge, perspectives and priorities in a really powerful way.”

Taft said despite all the damage to shorelines and the nation’s concerns over the years, regulators and the government had “essentially said that the contribution of waves from boats is negligible,” now proven to be untrue by the recent study.

It’s a concerning view for the nation with the study offering insight into how vessels from TMX could “significantly” increase wave energy in the inlet.

“What we detected was that, on average, 242 wave events are caused by tugboats each month, and if the pipeline expansion is built, and when it’s fully operational, there will be up to an additional 10 new tugboats per day, which would mean that would add around 300 new tugboat trips per month or more than double the wave energy from tugboats alone,” Taft explained, adding that there were other impacts and considerations from tankers, which produced the most powerful waves, as well.

He said the study found there were wakes from an average of six tanker transits each month, but if the pipeline is built there will be an estimated 60 tanker transits per month, representing a potential 900 per cent increase in wakes from tankers.

While the main focus of the study was identifying if there was a wave energy increase from vessels and not the impact the increase was having to shoreline erosion, Kerr-Wood Leidal said there was evidence to support the nation’s beliefs.

“Further study will be required to establish a definitive linkage between vessel wakes and erosion in the study area; however, the findings of this study provide evidence to corroborate TWN’s strong perception that vessel wakes are a significant contributor to the shoreline erosion they have observed,” the study report stated.

'Obvious' impacts from increased marine vessel traffic

For Aleck, the study reaffirms what the nation already knew.

“It's quite obvious to us and the naked eye when some of the foreshore starts to erode away,” Aleck said, adding that the nation has had to make embankments in order for some houses and the community’s graveyard to stay intact.

She estimated a third of the community on the inlet reserve is directly affected by foreshore erosion.

“It’s just reinforcing the things that I know, and that I see within the community,” she said. “My aunt and uncle's house started to have little cracks in the foundation and that was because of the foreshore erosion.

“The erosion to archaeological sites and the graveyard, I think that 100 per cent affects us all. To see proof and history in the soil and on the foreshore erode away into the inlet, and to never be regained, has an everlasting effect.”

She said the study supported the nation's Sacred Trust initiative to put a stop to the TMX expansion project.

“It’s yet another reason why we oppose such a huge expansion of a fossil fuel project within these narrow waters – there’s Chevron, there's Shell there's Trans Mountain, there's a chemical plant, a coal plant, there's CP Rail, BC Hydro – the inundation cannot be expanded anymore,” Aleck said.  “The report shows the effects and the real facts of the risks that we're up against at the end of the expansion, that we're being asked to bear.”



One of the changes the nation is hoping for, from the release of the study, is that regulatory agencies start considering all marine traffic when looking at impacts from vessels, rather than just on a project by project basis.

“It's pretty easy to point to one tugboat from one project and say that it's not having much effect, but when you look at the total effect of all vessel traffic, it's really changed how the water behaves in Burrard Inlet,” Taft said.

“That's one really important shift that we have to see … looking at the system overall.”

The study is just one important piece of the puzzle for Tsleil-Waututh’s ongoing work to protect the lands and waters of Burrard Inlet, which also include marine water and sound testing.

“It’s one tool among many different tools and many pieces of knowledge to better manage the environment and Burrard Inlet from a Tsleil-Waututh perspective, so things like erosion at cultural sites doesn't happen,” Taft said, adding that he hoped it would lead to discussions with the government and policy changes.

Aleck said the overall goal was to continue working to protect Tsleil-Waututh's way of life and the inlet.

“We know we can't get back to a natural, pristine state of what the inlet used to be, but we’re still trying to maintain and protect what it once was.”

Elisia Seeber is the North Shore News’ Indigenous and civic affairs reporter. This reporting beat is made possible by the Local Journalism Initiative.