Sea wall damage is a sign of things to happen in the midst of sea level rises and climate change, experts warn

The extensive storm damage to parts of Vancouver and West Vancouver’s waterfront on Friday could be a sign of what’s going to happen climate change and rising sea levels, experts warn.

Portions of the Stanley Park and Ambleside Park ramparts were left to look as if they had been hit by an earthquake, after strong winds helped produce a storm surge at the same time as a seasonal king tide.

Click to play video: 'Stanley Park seawall heavily damaged during king tide'

Stanley Park seawall severely damaged during king tides

Stanley Park seawall severely damaged during king tides

SFU soil science professor John Clague said the combination of these two factors was exacerbated by sea level rise and that similar harmful storms are expected to increase in frequency in the coming years.

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“It’s a double whammy because you’ve got higher sea levels, but you’ve also got the cyclical royal tides stacked on top of it, which means the types of events we saw last Friday will be more common, and they’ll. be more harmful, “he said.

According to the US Global Change Research Program, global sea levels have already risen by between 16 and 21 centimeters since 1900 – and speeds are rising. About seven inches of that increase has occurred in the last 29 years.

Estimates vary on how fast the oceans will continue to rise, but the federal 2019 Change of climate report projects The Vancouver area is likely to see more than 50 centimeters of growth above 2000 levels by the end of the century.

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The BC government has advised the municipalities to plan a sea level rise at 50 centimeters in 2050 and one meter in 2100.

“Global sea levels are rising slowly, slowly. Most people would not be aware of it because we have daily tidal fluctuations that go through four to five meters, so you just are not aware that this is happening slowly but persistently, ”Clague said.

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“But later in the century we will see that the plane of the sea is anywhere from about 30 centimeters to one meter from where it is today.”

When construction of Vancouver’s beach rampart first began in 1917, its designers had never foreseen the conditions it struggles with today, according to architect and urban planner Michael Geller.

“Even though it was built to today’s standard, they had never considered that there would be the level of sea level rise we are beginning to experience,” he said.

“What we’ll have to do is take a look at all the old seawalls … and rebuild a lot of it over time.”

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BC floods: Reconstruction of highways with climate change in mind

BC floods: Reconstruction of highways with climate change in mind – 28 November 2021

While it will be an engineering challenge to build more resilient seawalls, much of what sea level rise offers for cities is a planning challenge, Geller said, as flood design levels – the smallest height at which habitable structures can be built – are slowly rising.

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“The biggest challenge is not just being reactive,” he said.

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“These days, all too often, we are dealing with trying to remedy a problem that should have been prevented 20, 30, 40 years ago, when we first started talking about the potential consequences of climate change.”

Nearly a decade ago, the BC government laid out guidelines for coastal communities to help them adapt to the effects of rising sea levels.

The document proposes four strategies to manage the impacts, ranging from avoiding construction in potentially vulnerable areas, to adapting infrastructure, to protecting vulnerable structures to managed withdrawal in areas where the impacts cannot be managed effectively or affordably.

Some of these strategies are already being implemented.

In 2014, for example. City of Vancouver amended its building code to raise the level of flood defenses in flood-prone areas by one meter.

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In West Vancouver, where much of Ambleside Park was underwater during the storm, the Ferry Building Gallery escaped unharmed after being erected during ongoing restoration work specifically to protect it from sea level rise.

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However, older offshore infrastructure such as Vancouver’s beach embankment may pose a greater challenge in the coming years, and Clague said that even with major upgrades, we may have to expect them to be routinely damaged.

“I do not think we can abandon them, but we need to look at how we can better protect them,” he said.

“(They) can be just a saga – it’s a terrible thought, I hate to say it.”


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