The province raised the gates to the Red River Floodway south of Winnipeg on Sunday.
Water will now be diverted into the floodway channel to reduce river levels in the city.
The gates started opening at about 9:30 a.m. yesterday, and officials said it took about two hours before they were completely open.
The flood risk this season still remains low due to a slow melt, but that won’t change the outcome for parts of Highway 75 expected to close this week.
Updated flood forecasts are available daily by visiting Manitoba.ca.