The Manitoba government has begun operating the Portage Diversion amid concerns about ice jams and rising water levels in the Assiniboine River.
The diversion was put into operation on Saturday night, said Steve Topping, executive director of hydrologic forecasting and water management with Manitoba Infrastructure and Transportation.
"It is now controlling the flows to the lower Assiniboine, between Portage and Headingley," Topping told CBC News on Sunday.
"The intention is that we keep lower flows, stable flows; keep the ice in place to prevent ice jamming that could potentially over-top the Assiniboine dikes."
The diversion was operating at minimal levels, with water flowing at 900 cubic feet per second on Sunday morning and 2,500 cubic feet per second expected by day's end.
During last year's flood season, the structure diverted flows exceeding 20,000 cubic feet per second.
Officials are keeping a close watch on the river west of Portage la Prairie, Man. Earlier on Saturday, the province issued a high water advisory for the Assiniboine from St.-Lazare to Portage.
"The Assiniboine River from Shellmouth to Portage Reservoir still has a high potential of ice jamming. Water levels and flows are still increasing on the Assiniboine River," Topping said.
Since an ice jam formed on the Assiniboine near Spruce Woods Provincial Park, river levels have risen by about two metres.
Part of Highway 5 remains closed on Sunday due to water on the road.
Provincial Road 350, which was also closed to traffic, reopened on Sunday morning.