Assiniboine River, Souris River to soon peak at Portage Reservoir

Manitoba Flood Bulletin No. 13

Province of Manitoba – Manitoba Infrastructure’s Hydrologic Forecast Centre reports overland flooding and tributary flows are beginning to subside across parts of southern Manitoba. Flows in the Assiniboine River are continuing to rise.

Ice is still in place on northern rivers and tributaries. A high water advisory is in place for the Carrot River near The Pas. All major rivers in southern Manitoba are ice free.

The partial closure at the Gretna dike remains in place.

As of this morning, flow on the Portage Diversion channel is 19,176 cubic feet per second (cfs) or 543 cubic metres per second (cms) and flows on the Assiniboine River downstream of the diversion are 13,225 cfs (375 cms). That flow will be maintained today as upstream flows from Holland are delayed.  Flows may be increased to 15,000 cfs (425 cms) by tomorrow.

The revised Assiniboine River forecast suggests the Assiniboine and Souris rivers may peak at the same time at the Portage Reservoir. At Holland, with a weather forecast indicating no future precipitation, it is expected that flows will be approximately 43,000 cfs (1,217 cms) between the dates of April 12 and 13. It is anticipated the Portage Diversion will be above design flow of 25,000 cfs (708 cms) for approximately five days. Preparations for temporary flood protection measures are underway along the lower Assiniboine River and crews are preparing the diversion to handle emergency flows above 25,000 cfs (708 cms). Municipalities are preparing for flows of 16,000 cfs (453 cms) on the lower Assiniboine River.

A flood watch remains in effect for the area between Portage la Prairie and Headingley.

Water levels at James Avenue were measured at 17.4 feet this morning. With the floodway in operation, water levels at James Avenue are expected to remain within the range of 17 to 17.5 ft. for the next week as flows on the Red River recede and flows on the Assiniboine River increase.

A flood warning remains in effect for the upper Assiniboine River from the Shellmouth Dam to Holland but the warning for Oak Lake and the Souris River has ended as the Souris River has crested. The Assiniboine River is at or near peak in Brandon today at the 18th Street bridge.

A flood warning remains in effect for Pelican Lake, but it is near crest.

The Carrot River upstream in Saskatchewan has yet to peak at Turnberry. Water levels on the Carrot River within Manitoba are influenced by Carrot River flows and water levels on the Saskatchewan River where the two rivers meet. Conditions will be monitored because the ice is still intact in Manitoba, making ice jamming on both rivers a concern. The backwater effect of ice jamming will influence water levels on the Carrot River. It is difficult to estimate the timing and effects of ice jams on the two rivers.

The Saskatchewan River at The Pas is currently at approximately 41,988 cfs (1,189 cms). Due to high flows and the strength and thickness of ice, there is a risk of ice jamming.

Homeowners affected by this spring’s flooding are reminded to review their home insurance. Overland flood insurance was introduced by some insurers in Manitoba in 2016.

High water levels have led to a number of road closures across the province. Avoid driving through moving water as the water depth can be unpredictable and the current can push vehicles off the road.

Up-to-date flood information can be found at on the Province of Manitoba website or on Twitter at

For current highway conditions, call 511, visit, or follow the Twitter account at closures. A Manitoba 511 app is now available for download at

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