'We could take it': Manitoba better braced to face a 1997-level flood, experts say - Action News
Home WebMail Friday, November 22, 2024, 07:17 PM | Calgary | -11.4°C | Regions Advertise Login | Our platform is in maintenance mode. Some URLs may not be available. |
Manitoba

'We could take it': Manitoba better braced to face a 1997-level flood, experts say

As Manitobans build sandbag walls and watch riverbanks vanish under ever-swelling water levels,ghosts of the 1997 flood of the centuryhave returned exactly 25 years later.

'I wouldn't say that we wouldn't break a sweat,but I think we could take it'

Three men boat in an unidentified residential area south of Winnipeg during the 1997 flood. (Government of Manitoba)

As Manitobans build sandbag walls and watch riverbanks vanish under ever-swelling water levels, ghosts of the 1997 flood of the century have returned exactly 25 years later.

But this time around, experts saythe province is on more solid ground.

"No doubt there would still be a lot of work associated with it.But there's no question we are in a better position than we were in '97," saidRuss Andrushuk,assistant deputy minister for Manitoba Transportation and Infrastructure.

The same confidence is expressed by University of Manitoba civil engineering Prof. Jay Doering, an expert in hydrology who worked with the Manitoba Floodway Authority during the 1997 deluge and later on the floodway expansion committee.

"If a 1997 flood were to occur again,I wouldn't say that we wouldn't break a sweat, but I think we could take it and there really wouldn't be any reason for significant concern," he said.

This spring could test that theory.Communities along the Red River Valley are being told a major-level flood is almost a certainty.

On Friday, provincial flood forecasters said the coming flood couldapproach the volume of the 2009 flood, which wasthe highest since '97.

Manitoba has been pounded by one snowiest winters on record and by four significantprecipitation systemsin April alone. The third Colorado low in as many weeks is headed into the province this weekend, bringing 30-80 millimetres of rain to southern Manitoba.

Sandbags sit ready for pickup at the City of Winnipeg's public works yard on Waverley Street in April 2022. (Mario De Ciccio/Radio-Canada)

Last weekend, a similar system inundated Winnipeg with 50-70millimetres of rain and even moreto the south, including in the United States,onland that feeds into the Red River and its tributaries.

"We're going through a little bit crazy weather this year," said Fisaha Unduche, executive director of Manitoba's hydrologic forecast centre.

Manitoba has received 200 to 500 per cent of normal precipitationfor April, when there's typically 28 mm,Unduche said.

"Most creeks and rivers are already full with the previous system and the snow melt," and the ground is saturated, he said. "This precipitation could just add more water into the system."

The Red's swollen crest is now predicted to arrive in Manitoba in mid-May.

Flood coverage in southern Manitoba floods of 1826, 1852, 1950, 1979, 1997, 2009 and 2011. (Charlie Brockman/CBC News Graphics)

When the '97 crest arrived,more than 22,000 people had been chased out of about 20 communities along the valley, turning them into ghost towns, save for those designated to keep watch.

At its height,the Redwas the largest river in North America, covering 1,840 square kilometres of land. At its widest, the murky north-flowingtide measured 42 kilometres from west to east.

That flood was a wake-up call, Doering said.

Many of the flood protections in place had been designed fora one-in-100-year flood, set in place following the devastating 1950 event.

But climate change has made for wetter years and more regular floods and altered the outlook that was used to design the original Red River Floodway, Doering said.

The Red River Floodway was pushed to its limits during the 1997 flood. (Government of Manitoba)

The floodway, a 47-kilometre channel between St. Norbert and Lockportthat runs along the eastern edge of Winnipeg, divertssome of the Red's flow tomaintain a manageable river level in the city.

At the time the second-largest earth moving project in the world (second only to the Panama Canal), it was built between 1962 and 1968 andhas been credited with saving the city from major floods20 times.

Since it was created,most floods withincity limits have involved river levels just below 20 feet above normal winter ice levels with the exceptions of 1997 (24.5) and 2009 (22.6).

Without the floodway, the1997 crestwould have been 35 feet above normal winter ice level at James Avenuein downtown Winnipeg, the province estimated.

Peak levels this spring are expected to be around 20 feet James.

An aerial photo shows flooding in the St. Vital area in 1950, before the floodway was built. (Government of Manitoba)

When the floodway was built, it was heralded as being able to accommodate a water capacity forecastto occur every 160 years.

"When we ran the statistics in 1997, we realized it could carry a one-in-100-year flood.In fact, it was probably closer to about one in 90 years or even a little less than that," Doering said.

Following the '97 flood, the province embarked on a 10-year, $627-million expansion of the floodway.It is now rated at a protection level foraone-in-700-year flood.

In addition to the floodway expansion, changes in the past 25 years includeproperties in the Red River Valley being raised.

Older developments are protected to a one-in-100-year flood leveland newer developments must be at a one-in-200-year flood level approximately a '97 level plus two feet.

How does the Red River Floodway work?

8 years ago
Duration 0:24
The Red River flexed, puffed up its chest and threatened some properties in Winnipeg, but it has crested with little damage beyond some submerged riverbanks. The province activated the Red River Floodway on March 31 to control levels within the city.

"Since 1997, we've actually learned a lot," Transportation and Infrastructure Minister Doyle Piwniuk said during a recent flood update.

Highway 75, a primarylink between Manitoba and the United States,has been raised in severalkey areasby about 1.2 metres so that it can withstand higher levels of water though not quite '97 levels.

Highway 75 will most likely beclosed for a while this spring,Piwniuk said.

The cost of raising it all above '97 levelswould have been prohibitive, so the province decided instead tobuilda detour. Provincial Road 246, between Morris and Aubigny on the east side of the Red River, has been upgraded fromgravel to asphalt "to the highest loading standards" in order toprotect the major trade route,Piwnuiksaid.

There are also eight more community ring dikes along the valley for a total now of 16 and all meet the one-in-200-year flood level protection.

There have been significant enhancements as well to the City of Winnipeg'spumping structures and thehydroelectric network to provide better monitoring of river levels, Doering said.

Aflood management protocol manual hasalso been written, clearly outlining the roles everyone has to play, like a pro sports playbook.

An aerial image shows flooding outside the Morris ring dike in 2011. (Government of Manitoba)

Since the 1997 flood, more than $1 billion has been spent onflood mitigation efforts in Manitoba, preventing more than an estimated $7 billion in damages, the province's hydrologic operationswebsite says.

"I work with my counterparts across Canada, and we can be proud to say that Manitoba is always well-protected when it comes to floods," saidUnduche.

"The chance of having property damage or those kinds of issues in Manitoba will remain very rare."

That said, it's still no walk in the park to defend against a flood, saidAndrushuk: it requires a massive co-ordination of efforts to initiateemergency plans.

"It's all hands on deck. We start our preparation forspring flooding every year in January, with a lot of agreements forcontracting services, engineering services, materials and equipment," he said.

Much of that is behind-the-sceneswork, but there are still impacts the public cannot escape, such as theclosing of ring dikes, which encircleentire townsand eliminate the freedom of residents to come and go.

"Even though the communities aren't as affected they used to be, they still are in some ways," Andrushuk said.

WATCH | Protecting Winnipeg from a one-in-700-year flood:Original floodway versusexpanded one

1-in-700 year Red River flood simulation

2 years ago
Duration 0:41
How Winnipeg would fare against 1-in-700 year flood with the original floodway versus the expanded one. Video: Government of Manitoba

While we've become better at withstanding the spring onslaught from Mother Nature, that process must never end, Doering said.

Hydrology statistics and strain on infrastructureis something governments and municipalities must keep an eye on as climate change continues.

Andit's equally important to ensure the infrastructure can actually do what everyone expects, he said.

"We can't just build these things and assume that they're going to protect us for the rest of our lives."