Extra environmental controls have been added to the Trans Canada Highway realignment known as Plan B after heavy rains and snow melt caused problems at the construction site last week.
Jay Carr, an environmental assessment officer with the Environment Department, said part of the problem was the 35 mm of rain in a six-hour period, along with snow melt.
“There was a lot of water that went down in a relatively short timeframe,” he said.
The rain led to washouts and overflowing silt traps that were supposed to hold up under a one-in-25-year event.
But recent rains weren’t the first time environmental protection measures didn’t hold up and several silt fences have needed repairs or improvements to protect nearby waterways.
With the latest problems, Carr said the biggest issue was a washout at the former Encounter Creek site near Churchill where a dam holding back a diverted stream let go.
“A big gush of water came down and went through the culvert,” he said.
The rushing water didn’t follow the streambed it was supposed to and overwhelmed a sediment trap, he said.
Carr said the contractor was rebuilding the sediment trap and fixing the streambed to make sure the water follows the right path.
Sediment traps are designed to collect runoff in a pool where any sediment settles to the bottom and is eventually emptied to make room for more.
Carr said most of the sediment traps at the construction site are getting full and they will be cleared out soon.
“They’ve done their job,” he said.
Environmental monitors are supposed to be at the site regularly to make sure all the proper environmental protections are in place.
Carr said monitors have been on site during days when the weather required it or there was snowmelt.
Extra control measures have been put in place and more could be on the way if necessary, Carr said.
He also said recent cold weather has made it easier for crews to fix some of the problems than it might otherwise have been when the ground was softer.
“It would have to be done but it would just be more difficult,” he said.
The Plan B site wasn’t the only place where flooding caused problems and the Transportation Department closed several roads last week.
That includes Route 6 in Oyster Bed Bridge, where the road is closed for the next few days and Route 224 where work is expected to take about six weeks to finish.
Route 6 in Cavendish was closed temporarily but has since re-opened.
rross@theguardian.pe.ca
twitter.com/ryanrross
