Water flows through cut in crumbling Manitoba dike
A controlled breach at a failing embankment on the Birdtail Creek in western Manitoba is working so well that some evacuees are being allowed to return home.
The province used a large excavator to cut into the dike — a former railway ridge — overnight Monday into Tuesday.
The dike has been crumbling from the pressure of restraining the swollen creek tributary, so the cut was made to release some of the trapped water.
A section of the 30-metre-high embankment eroded and slid away on the weekend, and a second slide happened on Monday.
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The weakened wall is still holding back water but there was concern it could collapse and send a surge of water into the valley, first through Waywayseecappo First Nation and then through to the town of Birtle.
There is a culvert at the base of the embankment that has been plugged with ice, forcing up the level of the creek by holding back the spring runoff.
On Tuesday afternoon, provincial flood officials said water is starting to flow through the frozen culvert.
Manitoba Infrastructure and Transportation moved equipment in Monday night and the work to cut the dike began at about 9 p.m., about 200 metres west of crumbling section.
Crews dug about a metre deep and about 3½ metres wide, then used boulders and tarps to keep the sides from eroding.
The water began flowing, slowly, at about 3:30 a.m.
"We chose an area where it's very safe to do it in [and] we've always got good control on our release. So far it's working perfectly," Ron Richardson, director of water operations for the province, said Tuesday morning.
"We have no concerns, but it's an ongoing monitoring we have to do."
Officials say water is flowing through the cut in the dike into Birdtail Creek at a rate of 100 to 150 cubic feet per second, and they don't believe the creek will rise above its previous crest level as a result.
Crews are also pumping water out, but the province warned that the risk of the dike failing remains high because only the top 1½ metres of water is being removed.
Officials said they will be watching the situation closely over the next 24 hours.
More than 100 people have been out of their homes in Waywayseecappo and Birtle since the weekend, but some are being allowed to go home at Waywayseecappo.
Barb Cameron, who is in charge of organizing evacuees on the First Nation, said 12 people were told they could go home on Tuesday. Sixty-two people in those communities are now considered evacuees. Many are staying at a hotel in Russell, Man.
The breach, along with pumping of water and the slow release from the culvert are expected to reduce the risk of embankment failure, "however, risk of embankment failure is still high as only the top five feet of water will be removed from behind the embankment," the province stated in a news release Tuesday morning.
Nancy Evans, an evacuee from Birtle, was manning the barricades in town and told CBC News the water hasn't reached there yet.
She has noticed the level of the creek has dropped, though. There is more than three metres of distance from the river to the top of the dike now, she said.
The evacuation order for Birtle remains in place until at least Tuesday night, when it will be reassessed by officials who will decide whether to extend it or allow people back into their homes.
Flood warnings remain in place for the Birdtail Creek, as well as for the Assiniboine River from the Shellmouth Dam to Brandon, Man.