Open floodgates allowed Fraser to flood Sumas Prairie in 2021, suit alleges

An alleged blunder by the City of Abbotsford during the 2021 Nooksack River floods allowed water from the Fraser to also pour into Sumas Prairie and turned an evolving flood into one of Canada’s costliest natural disasters.

That provocative, and still unproven, allegation is now at the heart of a class action lawsuit filed by Sumas Prairie property owners against the City of Abbotsford. The lawsuit was certified last week by a Supreme Court justice, meaning it can now proceed to trial, where the plaintiffs’ claims will be put to the test.

The trial will determine whether the City of Abbotsford—and its taxpayers—are on the hook for potentially tens of millions of dollars in damages. But it will also shape the flood’s legacy, and reveal whether one of the valley’s largest natural disasters could have been mitigated.

A new story

On Nov. 14, 2021, the Nooksack River’s waters breached its northern banks and began flowing north towards Canada.

Normally, the water would have drained into the Fraser River through floodgates at Barrowtown Pump Station. But with the Fraser higher than the water in the prairie and Sumas River, those floodgates were closed to prevent water from the Fraser from rushing into the prairie. With nowhere to go, the Nooksack’s waters filled up the western part of Sumas Prairie like a bathtub. By Nov. 16, those waters started overtopping a key dike protecting the bottom of what had once been Sumas Lake. Within a few hours, the dike was blown apart, turning a bad flood into one of Canada’s most-damaging natural disasters.

That has been the standard explanation for why the flood was so bad. But now, lawyers for property owners suing the City of Abbotsford are arguing that the Fraser River didn’t just play a passive role in the Nooksack flood. Instead, the crux of a multi-million-dollar class action lawsuit rests on the allegation that over a 15-hour period on Nov. 14 and 15—just as water from the Nooksack was making its way towards Canada—City of Abbotsford workers allowed water from the Fraser River to also pour into the western part of the prairie, aggravating the flooding to come and potentially leading to the collapse of the dike.

Last week Supreme Court Justice S. Dev Dley certified the class action lawsuit, meaning it can proceed to a trial where lawyers will argue a case on behalf of all Sumas Prairie’s property owners.

The City of Abbotsford had contested certification of the class action suit, and a week-long hearing was held in April to determine whether the case could proceed. That hearing revealed the arguments both sides will use at trial. And the judge’s now-released reasons for his decision to certify the case confirm that the question of which-river-did-it will be central to the decision.

You can read the judge’s decision to certify the lawsuit here. It includes the judge’s breakdown of the arguments at the core of the case.

The allegation

The plaintiffs say that as water from the Nooksack River was pouring into Sumas Prairie from the United States, water was also entering the prairie from the Fraser River, through floodgates at Barrowtown Pump Station.

The suit alleges that normal operations would see the floodgates closed when water on the Fraser River side reached an elevation of three metres. The gates need to be closed so water doesn’t start to flow backwards into the Sumas River and Sumas Prairie. According to the plaintiffs, the Fraser reached a height of three metres at 8:25am on Nov. 14, but the floodgates weren’t closed until the following day, around 11:35am. By that time, the Fraser’s water had risen to a height of 6.87 metres.

The suit says that between 8:10pm on Sunday, Nov. 14 and 11:35am on Monday, Nov. 15, the water level in the Fraser River was higher than that of the Sumas River. That would mean that for 15 hours, water was allowed to flow from the Fraser into Sumas Prairie, contributing to the rise of the floodwaters. A former pump station employee declared in a deposition that he witnessed water from the Fraser River flowing into Sumas Prairie.

The plaintiffs say that additional water from the Fraser played a key role in the flood and collapse of the dike protecting the Sumas Lake bed on Nov. 16. As such, the suit alleges that flooding could have been mitigated if the City of Abbotsford ensured that it had enough properly trained staffers at the pump station who would have closed the floodgates earlier.

The defence

Those allegations, however, have not yet been proven as facts. That includes the most basic underlying assertions, including that the floodgates were actually open during the time in question. Abbotsford had been “critical” of the plaintiffs’ arguments throughout the hearing, the judge’s decisions reveal

Whether the floodboxes are found to have been open is the first question, but hardly the last. Even if the floodboxes were open, the plaintiffs will still need to prove that the amount of water flowing into the prairie from the Fraser was enough to have a measurable effect on the flooding.

To demonstrate that, the plaintiffs will need to provide a credible estimate both for how much water flowed from the Fraser into Sumas Prairie, and how that volume compares to the water that came from the Nooksack.

The city has argued that “it cannot be determined how much of the flooding was caused by [its] conduct.” In essence, the argument is that it’s impossible to actually determine the impact of water flowing from the Fraser into Sumas Prairie, if it did so.

Dley, the Supreme Court justice, disagreed in his finding. He accepted the testimony of Brian LaCas, a hydrologist witness for the plaintiffs, that it was possible to calculate how much water would have flowed into the prairie and what its impacts were.

That means the case may turn on the outcome of hydrological modelling and testimony from hydrologists like LaCas. That modelling hasn’t actually been completed yet—one benefit of certification means the plaintiffs are now entitled to receive documents and data that allow them to undertake such calculations.

It seems likely that Abbotsford will argue that any water that flowed from the Fraser into Sumas Prairie was a figurative drop-in-the-bucket compared to the water that arrived from the Nooksack and surrounding hillsides. But any such argument will depend on what the plaintiffs’ model reveals in the first place.

The trial

The certification of the class action lawsuit means the case can head to a trial where each side will present evidence, experts, and data on the floodgates and how much water each river contributed (or didn’t contribute) to the 2021 Sumas Prairie flood. Each side will also be able to attempt to poke holes in the evidence and witness testimony offered by their legal counterparts.

Certification means a trial can proceed, but it won’t start anytime soon. Class action lawsuits can take years to get from certification to trial, and BC’s court system is plagued by delays. At the same time, Dley turned around his certification ruling in a little more than a month—a relatively speedy decision given the variety of issues at play.

Beyond revealing critical arguments to be heard at trial, the certification hearings also focused on how a trial will treat and adjudicate damages and responsibility for the plaintiffs. A class action lawsuit boils the legal cases of a large number of plaintiffs into individual “representative” cases that stand for a whole group, or class.

For the case against the city, Dley ruled that property owners in the western Sumas Prairie and Sumas Lake bed areas should have their own representative plaintiffs. The breaching of the dike and alleged backflow from the Fraser had different consequences on owners in the western and eastern sections of the prairie. With each group having its own representative plaintiff, a trial judge will be able to issue differing judgments—and monetary rewards—for both classes.

Similarly, the judge ruled there should also be representative plaintiffs for property owners with a flood covenant and those without it. (The covenants are legal agreements related to the city’s responsibility for flood damage.)

The questions and the cost

A trial will focus on establishing key facts from the event, including how long the floodgates were open for, the amount of water that flowed into the prairie from the Fraser, and the actions that the City of Abbotsford and its staff could have been expected to take to mitigate flooding.

The trial won’t litigate every alleged failing of the City of Abbotsford. Core policy decisions are exempt from negligence claims, and the case won’t deal with questions about the insufficient height of the Sumas Prairie dike nor the city’s responsibility to warn residents of the impending flood.

Instead, the case may come down to the results of hydrological modelling by experts for the plaintiffs, and whether those findings withstand scrutiny by the City of Abbotsford’s lawyers and experts.

As for the potential payout to property owners—and cost to the city and its taxpayers—those damages will only be decided following a trial and decision about Abbotsford’s legal liability.

It won’t be known for years how much money could be awarded, pending a finding in favour of the plaintiffs. But it could be a huge sum.

One of the most recent similar cases is related to the flooding of land surrounding Lake Manitoba in 2011. Ten years after flooding, a 2021 trial found the Government of Manitoba liable. Manitoba agreed to pay $85.5 million to settle claims from property owners.

The Sumas Prairie disaster may have been the costliest in Canadian history, with billions of dollars in damages, and costs pegged at more than $1 billion. Much of the damage was suffered by private property owners and businesses. (There are more than 1,400 properties in the Sumas Prairie area and most were impacted by the flood.)

It seems unlikely that a judge will rule that the backflow from the Fraser River caused all the damages sustained in the Sumas Prairie flood 2021. A large amount of water from the Nooksack River undeniably flooded into the prairie following the atmospheric river.

But if a judge decides that water from the Fraser increased flood damages by even a relatively small per cent, the city could still be on the hook for a large sum of damages. And if preventable backflow from the Fraser is determined to have occurred and led to the collapse of the Sumas Prairie dike, the payout to owners—and cost to the city—may be much, much higher.