On-Site Magazine

Aftermath of Alberta floods

By MELANIE COLLISON    

Construction Infrastructure

Hardest hit town of High River still treading water

Alberta’s legendary winds thin the reek of burning steel as welders slice apart High River’s 1892 CP bridge over the Highwood River.

Blocking uprooted trees, the landmark bridge pushed the raging Highwood into High River’s low-lying downtown during Southern Alberta’s devastating flooding last June.

“There are not a lot of iconic things left in High River,” says Karen Lawrence Stevenson, who grew up in High River, a town of 13,000 about 64 kilometres south of Calgary. “It’s sad to see it (the bridge) go. What’s left?”

Stevenson fondly remembers her rite of passage at age 13 – the first time she jumped from the bridge into the cold mountain river below.

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The Highwood’s flowing capacity is expected to double with the bridge and its footings gone, the banks carved to remove that pinch point, and 70,000 tonnes of flood-borne gravel, rock and debris scraped out of sharp meanders upstream. That material will be used to armour dikes.

Normal flow for the Highwood in June is 30 to 70 cubic metres per second. The peak last June approached 1,800.

The meltwater slammed southwest High River like a tsunami. Within hours it filled the northeast like a swimming pool six metres deep, says the town’s communications manager, Joan Botkin.

With snow again piling up in the mountains and another winter’s runoff fast approaching, High River is strengthening its dikes west of the train bridge. It’s debating the best fix for a highway along the north boundary – opened eight months before the flood – to help it block water out instead of damming it in. 

And, anxious to launch long-term flood prevention action, the provincial government is hosting consultations on a proposed 500-cubic-metre capacity diversion channel around the town. That one project would cost between $100 to $300 million.

The channel and a dry dam west of Calgary are among $830 million in projects recommended by the province’s flood advisory panel.

High River was the hardest hit among 30 communities when a storm system snagged on the Rocky Mountains and dumped 325 mm of rain in a 540-kilometre sweep from Edmonton south to the U.S. border.

High water in six major rivers draining the eastern slopes killed four people and displaced up to 200,000. It did at least $6 billion worth of damage to towns, ranches, First Nations lands, and highways and bridges.

High River was completely evacuated by combine harvester, helicopter and boat after the power went out; cellular and landlines crashed, and the water treatment system flooded.

Ten days later, the first residents were allowed back. One neighbourhood at a time over the next three weeks, locals learned just how bleak their prospects were for recovery.

Few houses were untouched. Alberta Health deemed 558 homes “not fit for habitation.” Public facilities ­– town and Municipal District of Foothills offices, the hospital and clinics, schools, long-term care homes, the recreation centre – were badly damaged. Everything was coated in thick sludge contaminated by E. coli from the feedlot and manure-treated fields west of town.

Devastated homeowners dumped two years’ capacity into the landfill in the space of two weeks, throwing out appliances and mattresses, treasured photos and winter clothes, and everything used or stored in their basements, garages and sheds.

To help volunteers clean up the overwhelming mess, the province hired Tervita – a waste management company cobbled together in 2012 from CCS Corp., HAZCO and 11 acquisitions – on a $45-million contract.

“It wasn’t put up for tender because we were in a state of emergency,” says Kim Capstick, the province’s flood recovery task force spokeswoman. “The tender process takes months and months and simply wasn’t an option. We needed to get help to people right away.”

Starting in July, Tervita hauled debris and cleared sludge from neighbourhoods, storm sewers and storm ponds. It began work on the river, cleaned up parks and graded land downtown for a temporary business park created of sleek fabric structures by Sprung.

Tervita installed waste bins and diesel generators for the long process of emptying and drying 350 of the ruined houses. (The province covers only primary residences, so condo complexes containing most of the ineligible units had to contract their remediation independently.)

As winter approached, Tervita started on the most difficult 24 homes and began demolishing up to 30 houses and buildings that would cost more to salvage than they’re worth. Some still await a final decision.

Newly elected town councillor Cathy Couey said her priority was to restore hope among residents who fear the coming of spring, starting by improving communications between officials and citizens about work to prevent future flooding.

Ironically, a huge dump of snow trapped residents in their homes the week administration unveiled its flood mitigation plans.

High River is still planning to double its population by 2030. Projects on the drawing boards or already underway are to provide housing for more than 2,500 residents by the end of 2014. A temporary neighbourhood of 226 accessible units is under construction to meet immediate needs.

Meanwhile, about 1,000 residents are spending winter in hastily built modular housing camps, one just up Highway 2A and one near Calgary. Their future is uncertain, many having received no insurance settlement for overland flooding.

Of the estimated $6 billion in damage, $1.7 billion is insured losses. Ottawa has promised $2.8 billion to Alberta, with a substantial advance to come by March. The province has asked for $3.1 billion. “Disaster relief is cost-shared with the federal government up to 90 per cent,” says Capstick.

Within six months the province had allocated $110 million for erosion control, repairs, and protection of high-risk transportation infrastructure in cities, towns and rural areas along the Highwood, Bow and Elbow Rivers which swamped downtown Calgary.

High River will tender its $2.2-million portion: $1.2 million for diking and $950,000 for embankment work around where the bridge was. The massive repairs required on the town’s sewage infrastructure, at a cost of up to $10 million, are a whole separate problem.

More than 92 per cent of the 985 kilometres of highways damaged were open in less than six months, “which is quite remarkable,” says Capstick. Of the 80 schools damaged by flooding or rain only three stayed closed, two in High River and one in Calgary.

Highways and bridges were damaged throughout the western two-thirds of the MD of Foothills, which sprawls across 3,600 square kilometres south of Calgary. The MD provides primary services for 20,000 people.

In the first days after the flood, crews worked 20 hours per day on preliminary repairs.

Within three weeks, highway construction contractor Volker Stevin replaced the Sheep River bridge between Turner Valley and Black Diamond on the west side of the MD. Residents in the towns three kilometres apart had quickly wearied of a detour that took an hour to drive.

“The flooding completely washed out four bridges, and probably another 20 had varying degrees of damage,” says Mike Gallant, head of public works for the MD of Foothills. “By Black Diamond, the river cut a new channel and isolated seven families. We had that road temporarily repaired within a week, but a proper repair will cost millions, and you have to have [federal] department of fisheries and oceans and Alberta Environment’s permission to go into the river” to fix it.

“West of High River, on River Road, we had 50 homes with no way in or out, so we went to work right away. We started work at both ends.”

Initial repairs proceeded quickly, says Capstick, because Alberta Transportation has ongoing contracts with builders. “There’s still lots to be done to finish the repairs but we had to get the roads and bridge open,” she says. The MD has since contracted Volker Stevin to do a further $287,000 in bridge repairs. 

The province has hired international engineering giants AMEC and AECOM to assess a raft of proposed flood reduction projects. They will compare impacts on watersheds and future flooding, looking at such aspects as structure types, locations, impacts on property values and relocation of utilities.

For all participants, the agenda is driven by a fast-flipping calendar as Alberta recovers from the most costly natural disaster in Canadian history.

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