Floodgates, international politics, and the case for a new $700 million pump station

We have collected all our past coverage—including in-depth stories on the history and geography of Sumas Lake, Sumas Prairie, and the Nooksack River—in one location. Find it here.

A super-sized Barrowtown Pump Station may be needed to keep Sumas Prairie dry if the Americans don’t fortify the banks of the Nooksack River.

And if the US continues to allow the river to flood northward, Abbotsford’s mayor says maybe they should foot the bill for the $700 million project.A lack of confidence that the Americans will take the necessary steps to avert a future Nooksack flood is at the heart of new planning on how to better prepare the low-lying Sumas Prairie for future disasters. And it won’t be cheap.

The four flood-mitigation options unveiled last week are only a starting point for decisions. But they contain two main themes to protect Sumas Prairie from a future flood: a massive new pump station near the current Barrowtown facility, and the creation of a new floodway and dike system through the western part of the prairie. Together, the ideas show how last November’s disaster and the months since have altered officials’ confidence that the problem can be fixed at the source.

READ: Our story on the four options floated by Abbotsford officials.

COMMENT: The City of Abbotsford is looking for the public’s feedback on the plans. You can contact them, and get more details direct from city planners, here.

A new way of thinking

Just two years ago, Abbotsford took a very different approach to the Nooksack’s flood risk. In recent years, the city had begun focusing more on the river’s threat and had hired consultants to look at flood mitigation options and their costs. Those consultants, along with city staff and politicians, all agreed that the most logical solution was stopping the Nooksack flooding at the source. It was also the cheapest option. However, its more-than-minor downside was that Abbotsford had no power to actually raise the banks of the Nooksack.

So the city could only try to persuade. It chose an action that was hardly action at all: Abbotsford would lobby the federal government to lobby US officials to study the benefits of adding a dike along the Nooksack.

The big issue then, and now, was that the Americans aren’t particularly eager to keep the Nooksack from flooding north. Canada functions like a pressure release valve for the Nooksack’s waters. American officials have long worried that eliminating the overflow would exacerbate flooding downstream, through Washington and all the way to the Pacific Ocean.

Those worries continue, and while Whatcom County officials have declared their intention to undertake work to reduce flooding, they have not committed to raising the northern bank of the river. Instead, most early work has centred on plans to buy out some property owners in a larger floodway area that could be expected to take on water during a future disaster.

In Abbotsford, Braun is now doubtful that the Americans would bolster the Nooksack’s banks.

Hence Barrowtown

With that in mind, Abbotsford will be pushing for money to build a new $700 million mega-Barrowtown Pump Station that would aim to fix one of the central problems revealed last November.

A dike currently divides Sumas Prairie into two blocks. The eastern part of the prairie consists of the old Sumas Prairie lake bed, which sits around sea level. Any water in the eastern prairie must either drain into the ground, or be pumped several metres up to the Sumas River by the existing Barrowtown Pump Station.

We wrote more about how the complex system works, and how Barrowtown fits into it in late November. You can read that story here: The two Sumas prairies, and why the Barrowtown floodgates are so important.

The western prairie is higher in elevation than the lake bed and drained, usually, by the Sumas River. The headwaters of the Sumas River are just metres from the Nooksack River; they carry water north from the United States into Canada. Once north of the border, the river runs in a northeasterly direction; it crosses beneath Highway 1 near the Cole Road exit and hugs Sumas Mounton en route to the Fraser River. On its way, it passes through floodgates just west of the Barrowtown Pump Station. The Sumas dike exists to funnel any spillover in the same direction.

The water levels on the Fraser and Vedder rivers sometimes exceed that of the Sumas. Prior to the draining of Sumas Lake, the change in flow would cause the lake to grow in the spring and fall and recede in summer and winter. So the floodgates exist to prevent water from reversing the Sumas River’s direction and filling the prairie.

Last November’s floods demonstrated a key failing of a system that relied on pumps to drain one part of the prairie and gravity to drain another. It was, curiously enough, gravity that proved to be the challenge.

The record rains that caused the Nooksack river to burst its banks also swelled the Fraser and Vedder rivers. So as water from the Nooksack poured down the Sumas River basin and into Canada, it could not escape. The Fraser River was so high that the floodgates were closed; opening them would have allowed that river’s water to also flood into the western prairie.

So the water rose and rose and rose. It flooded farms, homes, and businesses in the western part of the prairie. Eventually, with the floodgates closed and nowhere else for the water to go, the water began to overtop the dike separating the two prairies. As it passed into the lower prairie, its speed and power blew a massive hole in the dike. Sumas Lake refilled.

The job

A new Barrowtown pump station would be tasked with doing what gravity couldn’t last fall. When gravity allows and they are open, the current floodgates allow about 220 cubic metres per second to pass through them en route to the Fraser. A mega-Barrowtown would be tasked with pumping that same amount of water when the floodgates are closed. Such a station would need seven times the pumping power as the current station, which is already one of the largest in North America.

But the scale is necessary because of the huge amount of water that can come from the Nooksack. Officials estimate that nine million cubic metres of water spilled into the area last November.

Abbotsford has pegged the cost of a super Barrowtown at around $700 million. That’s out of the price range of a municipality, and Abbotsford is planning to lobby the provincial and federal government to pay for a new pump station.

But Braun also suggested that the federal government train its eyes on the Americans.

When federal Public Safety Minister Bill Blair visited Abbotsford, Braun said he suggested hitting the US up for money for the project. “I did suggest … ‘I hope you guys are going to put on the table that the Americans should be contributing to this plan, because it’s their water that’s causing us this grief. You know, perhaps maybe even they should pay for the new pump station.’”

Without the Canadians offering something in return (or a consequence for not contributing), such an arrangement would seem highly unlikely. But other potential courses of action could have an effect on landowners and communities south of the border. They’ll definitely have an effect in Canada, where some residents may have to choose whether to remain in the valley or move elsewhere.

Next week, we’ll look at Abbotsford’s other big idea: floodways, buyouts, and a managed retreat from some low-lying areas. And, possibly, a bit of a dike along the US-Canada border.