Province takes heat for flood forecasting

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This article was published 18/05/2011 (4724 days ago), so information in it may no longer be current.

Manitoba Water Stewardship was under attack on Wednesday for providing faulty flood forecasting during the 2011 emergency.

Brandon city officials rushed to set the stage on May 6 for residential evacuations after a rapid rise in Assiniboine River levels seemingly caught everyone off-guard.

On that day, the Assiniboine River was metered at 30,000 cubic feet per second, with a level of 359.68 metres above sea level. The crest was projected for May 12-14 at between 360.43 metres above sea level and 360.58 metres at 33,500 cfs.

Crest dates then changed first to May 10-12, then yesterday to Saturday and a level as high as 360.82 metres above sea level. When the crest actually arrived last Saturday at midnight, peaking at 360.58 metres above sea level, flows reached 39,000 cfs.

"I’m not going to go there," said University of Manitoba civil engineering professor Jay Doering, when asked whether the province misses the expertise of previous flood forecaster Alf Warkentin, who piloted the province flood fight for some 40 years.

But Doering said that "historically, the province has done a remarkable job both in predicting the timing and the peaks."

He added: "Alf’s flood forecasts, as we know, tended to be very accurate."

Manitoba Infrastructure and Transportation Minister Steve Ashton said he "has a lot of respect" for Doering, and others providing advice, but that Manitoba Water Stewardship officials had access to real-time data that "others don’t."

"You have to be open to hearing questions asked about what you do," said Ashton, who is not an engineer by trade. "There’s actually a process in engineering called value engineering. To my mind, we are open to hearing advice. The information I give you, and I could show you my Blackberry, came to me at 2:08 p.m. … This is the real-time, decision-making process."

Ashton said there would be a post-mortem after the flood, where those who made the decisions on flood fighting will go over those moves.

"Why does Manitoba spend a billion dollars on flood mitigation?" Ashton asked. "It’s because after each major flood going back to 1950, we sat down and asked if we could do better. The answer is invariably, yes."

Steve Topping, the executive director of regulatory and operational services for Manitoba Water Stewardship, said his officials work closely with the Saskatchewan Watershed Authority and the North Dakota State Water Commission during flood seasons.

"We have full access to their real-time information," he said. "We have a number of gauging stations (in Manitoba) such as Shellmouth bridge, Russell, Millwood, St. Lazare … right up to Brandon. We have a great number of stations on the Assiniboine and on the Souris, we co-operate with the North Dakota State Water Commission. They allow us full access to their hydrometric gauges."

This year, 13 water metering crews monitored those gauges on the Assiniboine River and the Souris River, up from the usual three, with staff including Manitoba Hydro, Manitoba Water Stewardship, Manitoba Infrastructure and Transportation, and even Environment Canada.

"We recalibrate gauges on a three-day cycle, particularly where there’s active flooding," Topping said.

"The flood was so extensive that we had to step up our crews and that means training staff to operate the sophisticated Doppler radar velocity measuring metering apparatuses. There was a number of crews. We do cross-training with provincial staff and water survey staff who are experts in the field. We trained up for this, so many people could perform multiple functions."

Topping said there’s one variable he can’t plan for: Weather. Prospects for rain can drastically impact flood numbers on saturated soils.

"I think our forecasts are very good," he said.

"For instance, Brandon built dikes to 1,184 feet above sea level and their crest was 1,182.89. We are in a 300-year flood on the Assiniboine, and it’s beyond all of our historic data."

For Brandon, still watching dikes for seepage and damage from heavy water flows, news that water flow and level will progressively decrease was welcomed.

"These charts provide the city with data on what dates they will reach target elevations," Topping said. "It’s dropping a half a foot per day and the flow … is dropping about 1,000 cfs per day. Right now, we’re looking at the end of May and we could be looking at 18,000 cfs or more."

Ashton said he hoped to release more details about disaster financial assistance programs "by late this week or early next week at the latest."

 

» with files from Winnipeg Free Press