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Squamish Spit removal played no part in downtown coastal flooding event, according to experts

Numerous experts say there was no impact on the Dec. 27 flooding from the removal of the Spit.

Several experts say they don’t believe the removal of part of the Spit was a factor in the downtown flooding on Dec. 27.

The Squamish Chief spoke with numerous people about the coastal flooding in the downtown region to clarify if the Spit removal would have had any impact.

The Squamish Chief spoke with the District of Squamish, a meteorologist, a geoscientist, a professor in earth sciences, as well as other partners involved in the removal project.

None of the people contacted concluded that the Spit removal would have played a part in the flooding.

“I can say with confidence that the Spit removal was unrelated to the flooding. The flooding was purely a consequence of coastal water levels,” said the manager of municipal infrastructure, David Roulston.

“Whether the Squamish River is discharging into Howe Sound in its previous location or a couple 100 meters earlier into the estuary has no influence on the water levels in the Mamquam Blind Channel.

Local meteorologist, Jason Ross, also said that he did not believe the Spit removal played a part during the Dec. 27 flood event.

“The tidal water comes and goes no matter what and that being removed has no effect on the tide,” he said. “The currents can push into the sound and then it could be pushed back into the harbour. But in terms of the water level, that tide is there already.”

A local geoscientist, Pierre Friele, said in an email to The Squamish Chief that the spit removal did not contribute to the flooding as the Spit is not a part of the sea dike protection and there was very little wind driving the water inland. Ross previously reported very little wind on Dec. 27 as well.

The Squamish Chief sent John Clague, an emeritus professor in the Department of Earth Sciences at SFU, a photograph of where the flooding occurred and where the Spit had been removed plus previous studies about the Spit prior to interviewing in an effort to hear an outsider’s perspective.

Clague said he also believed in this instance that the removal of the Spit played no part in this particular flooding.

“In terms of the impact of that structure on what happened in late December, I don't think it had an impact,” he said.

Prior Spit removal studies and post-removal monitoring

The flooding on Dec. 27 came from entry points in the Mamquam Blind Channel located on the east side of Squamish’s oceanfront. The west side of Squamish’s oceanfront is protected by the CN Rail berm.

Numerous studies were completed before the removal of the Spit. One such study completed by LNC-Lavalin before removal modelled the change in wave height if the Spit was removed up to the yellow gate, which the study titled “Scenario 1.”

“The wave conditions close to the Squamish coastal boundary was very similar in both the current and Scenario 1 model runs,” reads the report.

The DFO said that professionals reviewed these studies and agreed that removal “was not going to present additional risk of flooding to the town of Squamish.”

The Natural Capital Assets Assessment prepared for the Squamish River Watershed Society (SRWS) even reported that “an intact estuary ecosystem could act as a buffer to riverine flooding and sea level rise.”

Executive director of the SRWS, Edith Tobe, said part of the removal project is to “increase the resiliency of the estuary to perform as a giant sponge and reduce energy during ocean storm surges,” which is what occurred on Dec. 27.

Some changes in wave height and sedimentation are still being monitored at the Squamish Terminals.

The SNC-Lavalin study did note a change of wave height near the Squamish Terminals. A later study noted a change in sedimentation near the Terminals. The Terminals is currently conducting a study of their own on the impacts of the removal.

"Initial results from recent survey data shows a significant increase in sedimentation rates in the West Berth," wrote Paul Morris, terminals manager, to The Squamish Chief in November 2022.

"We would be remiss not to express our ongoing concern about the unknown future financial impacts the removal could impose on the business, the viability to operate the west berth and the impacts to safety of navigation. But we are still awaiting a further monitoring report and survey data from the project proponents. Squamish Terminals continues to work with all stakeholders in hopes of finding a solution that works for all."

The DFO also noted that monitoring the effects of removal is ongoing as part of the project.

Council recently noted in November to the province that they have no objection to the removal of the next 550 metres removed of the Spit with the caveat that further removal does not negatively impact the Terminals.

When could sea dike upgrades begin?

The District said that their focus for the upcoming year is on improving the sea dike at Xwu'nekw Park, which is the most expensive item in the 2023 budget at $11.6 million, and they previously acknowledged the lack of an improved sea dike in this area played a major role in the recent coastal flooding.

Federal permit applications to improve the sea dike were submitted in mid-2021, but the District has yet to receive the Fisheries Act authorization from the Department of Fisheries and Oceans (DFO). The DFO confirmed they received an application for Fisheries Act authorization in January 2022 and when the two met in November 2022, the District had not yet met all the information requirements the DFO needed.

Roulston said the DFO wanted more information about the habitat compensation plan. He said the hope is to get the DFO the information they need by the end of January or early February and hopes construction to upgrade the sea dike could begin in August, so long as everything is approved.

After press deadline, the Flood Safety Team of the Ministry of Forests responded to a request for comment from The Squamish Chief. It said that, in the Ministry's opinion, it is highly unlikely that the unregulated berm had any effect on the flooding that occurred.

The Squamish Chief reached out to the Squamish Nation. A Nation spokesperson said they did not feel a comment from the Nation was required.

*Please note that we have corrected a typo in this story since it was initially posted. We corrected LNC Lavalin to SNC-Lavalin. On Jan. 17, we also added a comment from the Ministry of Forests.

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