An unstable weather system is expected to bring between 20 to 60 millimetres of rainfall in portions of southern Manitoba between today and Wednesday. This weather system is expected to affect the Interlake area and the Assiniboine, Dauphin, Souris and Red River basins. However, the amounts and timing of these events is still uncertain. Manitoba Water Stewardship is monitoring weather conditions as they evolve and re-evaluating the potential impact on river level forecasts. If significant rain occurs, water levels on streams will rise. The amount of the rise will depend on the amount of precipitation received.
Food warning are in place for streams and rivers in the Dauphin Lake Basin; streams and rivers east of the Duck Mountains; the Souris River from Melita and all downstream reaches; the Assiniboine River downstream of the Shellmouth Dam to Portage la Prairie; Pipestone Creek, all reaches; Oak Lake and Plum Lakes; Plum Creek to the Souris River (including the town of Souris); the Qu`Appelle River in the St-Lazare area; and the Assiniboine River downstream of Portage la Prairie
A high water advisory is in place for all major lakes in Manitoba.
Flood Response
In Brandon, provincial crews are adding a third layer of super sandbags along 18th Street and adding another layer to strengthen the super-sandbag dike at First Street. Crews are setting up large flood-tube barriers along PTH 110 to keep the highway open. The City of Brandon is also raising the earthen dikes within the city limits.
Approximately three homes in the Kirkcaldy Heights area of Brandon have flooded basements due to water backing up through a culvert. City crews sandbagged the culvert and water has stopped flowing.
In Minnedosa, the high school and low-lying areas are being sandbagged as a precaution.
The RM of Cornwallis will receive 1,800 sandbags from the provincial supply.
Work continues to elevate dikes at the Sioux Valley First Nation provide flood protection to 1,207 feet.
Repairs are ongoing to the dikes around Oak Lake. Minor flows are spilling over a few reaches of the dike and into the Plum Lake system.
Baie St. Paul to Headingley
As a precautionary measure, volunteer crews are helping to raise dikes along the Assiniboine River by two ft. in this area so that dikes are at least two feet above current water levels. This is to provide additional protection as a precaution should there be rain and wind set-up that could cause waves. Approximately 40,000 provincial sandbags have been provided to support sandbagging efforts.
Work is continuing on an ongoing basis to reinforce and strengthen the provincial dikes from Portage la Prairie to the Baie St. Paul area to prepare for rain and wind effects as well as sustained flows on the Assiniboine River.
Other areas
Cottage owners in the Dauphin Lake area are sandbagging. The rural municipality is co-ordinating the sandbagging effort and so far protection has been completed at 20 properties.
The RM of Lawrence and Manitoba Aboriginal and Northern Affairs communities are putting up flood-tube barriers near Dauphin Lake and Lake Manitoba to protect properties.
An agreement has been reached with Lake St. Martin and Little Saskatchewan First Nations to raise their existing dikes to 809 ft. to provide protection from high water levels and wind and wave action on Lake St. Martin. The province has committed to provide whatever technical assistance is required and to work with both First Nations to raise the dikes as soon as possible. The province is also providing pumping assistance to these communities.
A provincial sandbag machine is operating at O-Chi-Chak-Ko-Sipi First Nation near Crane River to provide sandbags for the community and surrounding area.
Manitoba Agriculture, Food and Rural Initiatives continues to work with 34 producers in the Shoal Lakes area. Work is underway to ensure livestock have enough feed and to develop plans to move herds as required due to rising lake levels.
There are 1,141 people evacuated from their homes, largely due to lack of safe road access.
There are 111 provincial roads affected by flooding, with 69 closed. There are approximately 704 municipal roads closed.
Assiniboine River
Water levels on the Shellmouth Reservoir have increased by 0.19 ft. since yesterday to 1,414.39 ft. Flow into the Shellmouth Reservoir is approximately 13,700 cubic feet per second (cfs). The Shellmouth Dam will be operated to maintain outflows at 12,000 cfs today.
St-Lazare’s water levels are near crest and have increased 0.07 ft. since yesterday to 1,292.08 ft. St-Lazare’s community flood protection level is 1,294.4 ft. providing approximately 2.7 ft. of freeboard at current water levels.
Water levels at Sioux Valley were measured late yesterday afternoon at 1,204.03 ft., with a forecast peak between 1,204.7 and 1,205.2 ft.
Water levels on the Assiniboine River at the First Street Bridge in Brandon are 1,181.33 ft, an increase of 1.16 ft. since yesterday, exceeding the record level of 1,180.0 ft set in 1923 at the First Street Bridge.
The Assiniboine River forecast was revised yesterday with record flows forecast for the Brandon area at 33,500 cfs between May 12 and 14. Peak water levels are forecast to be between 1182.5 and 1183.0 ft.
Flows in the Portage Diversion channel this morning were at 20,000 cfs. Inflows upstream of Portage la Prairie are 37,800 cfs. Flows on the Assiniboine River at the diversion are 17,850 cfs and will be held at about 18,000 cfs for an extended period of time.
Water levels on the Assiniboine River from Baie St. Paul to Headingley are forecast to receive sustained high flows for an extended period of time. Manitoba Water Stewardship is managing the Portage Diversion to keep flows on the river at Portage around 18,000 cfs, similar to flows occurring today. Despite regulation of Assiniboine River flows, inflows from local run-off following future rainfall could increase water levels in the area a further 0.5 ft. for a few days after the rainfall event.
Without flood protection provided by the Shellmouth Reservoir and the Portage Diversion, water levels in the Baie St. Paul to Headingley area would be about four to five ft. higher than today’s levels.
Red River
Water levels just upstream of the Red River Floodway inlet are 763.86 ft., with flows of 73,400 cfs. Flows in the floodway are approximately 34,000 cfs.
The Red River has held a sustained open-water crest at 19.6 ft. today and for the last three days at James Avenue in Winnipeg. Flows at James Avenue this morning were approximately 58,800 cfs.
Souris River
Water levels at Melita are 1,410.36 ft. today, down 0.03 feet.
Water levels on Oak Lake increased 0.16 ft. to 1,412.04 ft.
Lakes
Water levels in large lakes across Manitoba continue to increase. A summary of water level rises is attached.
Forecasters have estimated peak wind-eliminated water levels for Lake Manitoba and Lake St. Martin, both forecast to reach high water levels that are unprecedented since regulation of the lakes began in 1961. These forecast elevations are preliminary at this time and may be revised with major weather changes and as computer models are refined.
Maps indicating wind-eliminated inundation areas around the south basin of Lake Manitoba are being provided to the rural municipalities surrounding the lake to help land owners prepare for high water levels. Manitobans can contact their RMs to better understand the extent of land impacted by forecasted peak water levels. It is advisable that the public make flood preparations in light of these forecasted high water levels.
Outflows from Lake Manitoba were estimated at 13,200 cfs as of late yesterday. This flow value will be assessed later today.
Open water is visible on the lower half of Lake Winnipeg’s south basin. The risk of shoreline ice pileup today is low on all assessed lakes.
Other Major Waterways
The flood warning for Dauphin Lake and all inflowing tributaries remains in effect.
The flood warning for streams influenced by snowmelt in the Duck Mountains within the Lake Winnipegosis Basin remains in effect.
For more information, see www.manitoba.ca/flooding. The most up-to-date highway information is at www.gov.mb.ca/mit/roadinfo or 1-877-MBRoads (1-877-627-6237) and on Twitter by following @MBGov.
