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A failure to anticipate

Flood forecasting was the least of the problems in 2011-2012

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The flood of 2011 and 2012 was the most expensive disaster in the history of Manitoba. The cost to the provincial and federal governments has surpassed $1.2 billion and is still rising. Add the out-of-pocket costs to flood-affected Manitobans and the real total easily exceeds $2 billion.

Though flooding was widespread, the primary cause was the flows on the Assiniboine River were very high for a very long time. If floodwaters had not been diverted north into Lake Manitoba via the Portage Diversion, a catastrophic flood covering hundreds of square kilometres between Portage la Prairie and Winnipeg would have ensued. Winnipeg would have been largely spared as it is well protected by flood defences.

So extreme was the Assiniboine flood that had its flow not been diverted, the river may well have carved a new channel as it has done on several occasions since the last glaciation. This would have been good for the walkway at The Forks, but bad for someone with a new river in their front yard.

In the aftermath of the flooding of 2011 and 2012, the province created two task forces. One was led by civil engineer Dave Farlinger to provide a provincial overview (The Manitoba 2011 Flood Review), the other by economist and management consultant Harold Westdal to examine events at the epicenter of flooding: The Lake Manitoba and Lake St. Martin Regulation Review.

Both task forces contained a mix of experts on water-related issues and stakeholders from the affected communities. After extensive consultation with the public, hydrologists, engineers and public officials, two substantive documents have been produced and were released to the public on April 5. The recommendations are many and wide-ranging and will help in future flood preparations.

A similar procedure followed the 1997 Red River flood, which in fact produced far less damage than the flood of 2011 and 2012. That effort was also led by Dave Farlinger and yielded a set of recommendations that resulted in the expansion of the Red River floodway and revised land-use policy on the Red River floodplain. As a direct result of that prudent decision-making, we can now handle historically high water levels on the Red River with comparative ease.

It wasn't cheap -- the floodway expansion alone cost $700 million -- but the cost-savings in averted flood damage have already been enormous.

It is now time to do the same on the Assiniboine. The recommendations from both reports are sensible and balanced. They range from how we might improve flood forecasting to how flood-related information might be better communicated, how we need to co-ordinate the flood response efforts better on First Nations communities, how we might train officials in flood-affected communities better, how flood compensation programs can be run more effectively, to what new flood works are needed. I'll focus mostly on the last, which are the big-ticket items.

Some will be deeply unhappy with what was not included in the reports, such as a discussion of compensation programs for deliberate flooding, but this was not in the mandate of either committee: That was a deliberate political omission.

I couldn't help but notice the recommendation to hire a professional to communicate flood-related information to the public. As much as I have come to enjoy Steve Ashton's press conferences, that is probably a good idea. Ashton has transformed political evasiveness into high art.

The initial media response to the release of both reports focused primarily on deficiencies in flood forecasting. It strikes me the flood managers are being hung out to dry in the search for a headline. Yes, we do need better forecasts, and this involves new equipment, approaches and people. I can see the ribbon-cutting ceremony on our new flood-response centre already.

But deficiencies in flood forecasting did not materially affect the outcome of events in 2011 and 2012. The sideshow at Hoop and Holler, which could have been avoided with better forecasts, was just that: a relatively minor event that diverted attention from a much larger disaster elsewhere.

Manitobans were in fact well-served by competent flood managers who made difficult decisions to minimize the overall damage under extraordinary circumstances.

The disaster occurred not because forecasts were flawed, but rather because flood managers did not have the tools to implement effective solutions. With the recommended flood works, they could have turned a large disaster into something much more manageable, as we now do routinely on the Red River.

Ground zero was Lake Manitoba and Lake St. Martin. Too much water entered and too little left, resulting in catastrophic flooding. Now, two years after the onset of the flood, more than 2,000 Manitobans are still without a home.

A key recommendation from the Westdal task force is to increase the outflow capacity from Lake Manitoba. Inflows from the Portage Diversion have exceeded expectations over the years, and the Fairford water control structure is too small.

Equally importantly, this must not simply transfer the problem to downstream residents on Lake St. Martin and the Dauphin River. More outflow from Lake Manitoba needs to be co-ordinated with increased outflow from Lake St. Martin.

To this end, there is a recommendation for the "emergency" channel between Lake St. Martin and Big Buffalo Lake to be made permanent: This helped alleviate a bottleneck in draining water from Lake Manitoba over the winter, as flows needed to be reduced to avoid flooding on Lake St. Martin.

Another set of recommendations stemming from the two reports concerns managing inflows to Lake Manitoba. Central to this is better water management on the Assiniboine River. The Farlinger task force recommends reviewing a variety of options, including expansion of Shellmouth and a long mooted Holland Dam.

On the lower Assiniboine, a key recommendation is to increase the channel capacity between Portage la Prairie and Headingley from its current 18,000 cubic feet per second.

Tellingly, the Westdal task force went off the board to make the same recommendation, even though it was not part of its original mandate. They note the channel capacity has deteriorated since the 1970s and suggest restoring dikes so that 22,000 cfs can be carried east of Portage. This reduces the need to divert water to Lake Manitoba during an Assiniboine flood.

The Farlinger task force made an additional and notable recommendation: that an engineered and permanent wasteway channel be added to the lower Assiniboine for basically the same purpose as the Hoop and Holler cut in 2011: to prevent an uncontrolled blowout of the dikes on the lower Assiniboine during extreme flooding.

Peak flows on the Assiniboine reached in excess of 53,000 cfs upstream of Portage la Prairie in 2011. The lower Assiniboine at its peak carried close to 19,000 cfs for a short period of time, and the rest, 34,000 cfs, was sent through the Portage Diversion to Lake Manitoba. The sum total was just enough to prevent the Assiniboine from overtopping its banks between Portage la Prairie and Headingley, but it was close.

Hydrologists tell us that in a maximum flood peak, flows on the Assiniboine could be at least 5,000 cfs higher than in 2011. In such a case, the Portage Diversion and the lower Assiniboine cannot carry all the water.

A wasteway channel would divert the overflow to where it would do least harm, presumably unoccupied farmland, though details in the report are scant. If the Assiniboine capacity is increased to 22,000 cfs, a wasteway channel might need to carry about 2,000 cfs, or roughly enough water to flood 15.5 square kilometres of land each day to a depth of 0.3 metres.

For the residents of Lake Manitoba and Lake St. Martin who were most severely affected by the flood of 2011 and 2012, the sound recommendations from both task-force reports provide room for optimism and direction forward.

Increased dike capacity on the lower Assiniboine, enhanced water storage on the upper Assiniboine and possibly an additional drain from Lake Winnipegosis to Lake Winnipeg would reduce inflows to Lake Manitoba. Increased outflows from Lake Manitoba and Lake St. Martin would help the other side of the flood equation. Together, they would ensure future floods would produce far less damage for far less cost than they did in 2011 and 2012.

These structures will not be cheap, but they are necessary. Manitobans cannot afford another disaster on the scale of 2011 and 2012.

A half century ago, a man with remarkable vision took the then-controversial steps to protect Winnipeg by building the Red River Floodway. He was ridiculed for squandering the public purse on "Duff's Ditch." But the legacy of Premier Duff Roblin rests in large part on his foresight that has saved Manitobans many billions of dollars.

Premier Greg Selinger, the ball is now in your court. How do you wish to be remembered?

Scott Forbes is an ecologist at the University of Winnipeg. He owns property at Twin Beaches on Lake Manitoba and was among the many flood victims of 2011 and 2012.

Republished from the Winnipeg Free Press print edition April 13, 2013 J6

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