Alberta begins planning of flood-mitigation projects in wake of disaster

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The Alberta government is taking the first steps toward building a series of massive projects to keep the damage caused by future floods in check – including a water diversion channel around the town of High River, and a dry dam upstream of Calgary.

"We want to get them done as soon as possible," Alberta Premier Alison Redford told reporters Thursday.

"Our hope is that we're going to be able to do some work in spring."

The province is trying to avoid a repeat of the river floods that hit communities across southern Alberta in June. The high waters killed four people, displaced tens of thousands and caused at least $6-billion in damages.

Without giving a dollar figure, the province is ordering environmental reviews and public meetings on the diversion route and dry-dam projects, from a total of $830-million in projects recommended by a flood advisory panel.

The City of Calgary will also receive a grant for a feasibility study on a proposed underground water tunnel that Mayor Naheed Nenshi once likened to "science fiction."

In the event of a flood, the tunnel would be used to divert Elbow River waters through a five-kilometre-long passage under 58th Avenue, and away from the inner city.

Although Mr. Nenshi said he was originally circumspect about the giant storm-sewer scheme, he's now taking the advice of water management experts from the Netherlands who he said told him: "This kind of thing is very common, and it actually makes a lot of sense."

The planned dry dam – so named because water would only be held back during a period of high river flows – would be located upstream of Bragg Creek, Alta., to manage flows on the Elbow River.

In High River, the diversion channel with a price tag of $100-million to $300-million will divert Highwood River waters around the town.

But the channel alone won't be enough to mitigate all the effects of a flood the size of this year's disaster.

The government said while normal flow rates for the Highwood River in June are between 30-70 cubic meters per second, the peak flow rate of the river during the June flood was between 1,500-1,800.

The diversion will accommodate a flow of about 500 cubic meters per second.

High River Mayor Craig Snodgrass said with the province's help, the town is taking other steps to mitigate flood damage, including raising berms and removing river bottlenecks.

But he wants the crucial diversion channel in place within two years – before the next big flood, he hopes.

"We are crossing our fingers for a couple of years," the mayor said.

Ms. Redford said the government is still deciding whether to proceed on other flood-mitigation measures recommended by the advisory panel, including those for the Bow River.

"This is not a final announcement."