Stormwater threatens to close Trans-Canada
By: Cathy Ellis
| Posted: Thursday, Jun 21, 2012 06:00 am
Massive amounts of rock and debris from recent heavy rains have swept down Five Mile Creek in Banff National Park, threatening to close the Trans-Canada Highway just west of the Banff townsite.
A culvert that is supposed to carry water from the creek under the highway and into the Bow River is blocked, forcing Parks to divert the creek’s flow towards the Bow Valley Parkway and into the ditch along the highway.
Parks Canada officials are saying they are doing everything they can to keep the highway open.
“The Trans-Canada Highway is critical to the economy and everything else – and this is truly an emergency situation,” said Douglas Kerr, Parks Canada’s operations manager for highways and roads.
“There’s 30,000 to 40,000 vehicles a day at the peak time of year and there’s no alternate route other than Highway 3 to the south and the Yellowhead to the north.”
In 1999, huge amounts of debris were washed down Five Mile Creek following intense rainfall, blocking the culvert and forcing rock and mud across all four lanes of the Trans-Canada Highway.
The highway was closed for several days as a result.
Following the most recent rainfall two weeks ago that put the area on flood watch, the multi-plate culvert that runs under the highway – four metres in diameter and about 50 metres long – is once again plugged.
On Tuesday (June 19), Parks Canada began diverting the creek at the top of the alluvial fan down the other side, pushing flows towards the Bow Valley Parkway.
Up until then, most of the water that couldn’t get beneath the highway due to the plugged culvert had had been running east and west along the highway ditch.
“That’s how we’re managing the flow until we can mobilize the manpower and the equipment and we can dig it out,” Kerr said, noting that work would take almost a week to complete.
“We don’t know what’s in there blocking the structure, but we’re hoping it clears out easily, but if it’s a lot of trees and big material in there, then it gets a little trickier.”
The water going to the Bow Valley Parkway is flowing south, pooling under the Trans-Canada Highway-Bow River bridge, then proceeding to another culvert that takes it under the railway line.
Some of the pooling water is seeping under the Bow Valley Parkway and is coming out three feet from the railroad tracks.
Kerr said Parks Canada is also working closely with Canadian Pacific Railway so there’s no impact on the train tracks below.
“There’s a limitation on the culverts at the CP Rail to take that water through,” he said. “So we have to monitor it very closely so we don’t overwhelm the culverts CP has.”
Parks Canada – which has been hard hit by the Harper government’s budget cuts to the tune of about $29 million – is known to have little money for highway maintenance, including culvert maintenance.
Historically, Ottawa has given Parks Canada money from emergency funds when the Trans-Canada Highway gets blocked or flooded.
“Right now, keeping the Trans-Canada Highway open and unobstructed is the most important thing and down the road Parks Canada will figure out how the bills will be paid,” Kerr said.
“We certainly class this as an emergency situation that, if left unattended, it will go across the Trans-Canada Highway, at which point we’re closed.”