Assiniboine River Peaked Between The Shellmouth Dam and Virden.

Source: Manitoba Government Media Release - April 21, 2023

FLOOD UPDATE #5

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Province Advises Outflow from Shellmouth Reservoir to Increase

Manitoba Transportation and Infrastructure’s Hydrologic Forecast Centre advises it will increase flows from the Shellmouth Reservoir to manage the level of the reservoir.

The Assiniboine River has peaked between the Shellmouth Dam and Virden. Levels are gradually rising downstream of Virden as the runoff from spring melt and local tributaries contribute to the flow.

Outflow from Shellmouth Dam will be increased today (Friday) to 800 cubic feet per second (cfs) from the current 300 cfs. The province will continue to monitor conditions in the upper Assiniboine River as well as downstream river levels.

Manitoba Transportation and Infrastructure advises the public to take precautions as the rise in water levels may create unsafe conditions on the river and along the shoreline.

The Hydrologic Forecast Centre reports that while most tributaries have already peaked or are near their peak within the province, flows and levels continue to rise in major rivers, including the Red, Assiniboine and Souris rivers.

The centre advises the effects of the recent weather system to southern Manitoba are still being reviewed and analyzed. Run-off from latest precipitation is not expected to start until next week, as temperatures in most areas will remain around the freezing point until early- to mid-next week.

The Portage Diversion is now in operation to minimize the effects of ice jamming on the Assiniboine River east of Portage la Prairie and to control river levels in Winnipeg and areas along the Assiniboine River downstream of Portage la Prairie. Operation of the Red River Floodway is also underway to reduce water levels within Winnipeg.

The Manitoba Emergency Measures Organization (EMO) continues to work with all local authorities and emergency management partners to provide guidance and support in response to the spring flood. This includes reviewing existing emergency plans, information sharing and preparing resources used in flood response. Additionally, Manitoba EMO continues to work with Indigenous Services Canada to support its response measures with First Nation communities.

As the melt continues, updated flood information will be posted at https://www.manitoba.ca/flooding/.