June 30, 2011
Flood Bulletin #88
Flood Response
- Close to 3,000 Manitobans remain evacuated from their homes.
- There is some warm weather and a reprieve from heavy rains in the forecast for the Souris and Assiniboine River basins.
- Flood forecasters continue to watch water levels on the Souris River and track the crest as it comes north.
- The Souris River peak is moving quickly and after discussions with the U.S. National Weather Service, the forecasters moved the peak date range up by one day yesterday for communities along the Souris River in Manitoba.
- Preparations for a flood of record along the Souris River in southwest Manitoba continue.
- Several projects are being managed by municipal and provincial officials work around Souris, Wawanesa and Melita and are on schedule.
-
In Souris, flood-protection measures include:
- the swimming pool, water treatment plant, the waste-water treatment plant and residential areas which are at risk;
- 10 semi-trailer truck loads of sandbags which arrived yesterday with 20 more scheduled to arrive today, totaling over 300,000 sandbags.
- There are approximately 65 workers dedicated to the response, from the Town of Souris, the province and contractors. There are approximately 150 local volunteers as well.
- Helicopter lifts of super sandbags to once again bolster the dam in Wawanesa will take place over the next two days.
- The City of Brandon has responded to a call for sandbag crews and a 30-person team is in place.
- Roadways will be restricted or closed as waters rise and some flood-proofing projects are running 24 hours a day so motorists and the public are advised to be careful around workers and equipment.
- The communities of Meadow Portage, Spence Lake, Benyks Point and Woods Creek along the north end of Lake Manitoba continue to be impacted by rain, high lake levels and significant wave action from south winds. Communities and residents continue to sandbag properties at risk of flooding where it is possible.
- The province continues to examine options for improved drainage of Lake Manitoba including surveying in the Fairford area.
- At this time are 2,989 Manitobans are evacuated.
Flood Forecast
Souris River
- The U.S. National Weather Service (NWS) yesterday increased the forecast peak flow at Westhope, N.D., to 30,142 cubic feet per second (cfs) on July 4, which is an increase of approximately 300 cfs since the June 27 NWS forecast for Westhope. A revised forecast was developed for the Souris River. The lower end of the forecast range was developed assuming favourable conditions, with no further rain, and the upper end of the forecast range was developed assuming unfavourable conditions which assume 25 to 30 millimetres of rainfall over saturated soils. The upper end of the forecast may change if additional rainfall is forecast.
|
|
Melita |
Souris |
Wawanesa |
|
Spring Peak |
|||
|
- Flow (cfs) |
16,800 |
18,000 |
19,000 |
|
- Level (feet) |
1,411.64 |
1,359.86 |
1,157.97 |
|
- Date |
April 22 |
April 23 |
April 26 |
|
2011 Maximum Prior Peak |
|||
|
- Flow (cfs) |
16,800 |
20,300 |
25,600 |
|
- Level (ft.) |
1,411.64 |
1,361.36 |
1,160.63 |
|
- Date |
April 22 |
June 15 |
June 16 |
|
Late June – Early July Peak |
|||
|
- Flow (cfs) |
31,000 to 33,000 |
34,000 to 36,000 |
34,000 to 38,000 |
|
- Level (ft.) |
1,413.75 to 1,414.5 |
1,368 to 1,368.5 |
1,164.5 to 1,165.5 |
|
- Date |
July 4 to 7 |
July 5 to 9 |
July 7 to 11 |
- Forecast flow, water level and date of occurrence were also developed as previously described for a few intermediate locations along the Souris River in Manitoba and is listed in the table below.
|
|
Napinka |
Hartney |
PTH 10 |
|
July Peak |
|||
|
- Flow (cfs) |
31,000 to 33,000 |
32,000 to 34,000 |
34,000 to 38,000 |
|
- Level (ft) |
1,408 to 1,408.5 |
1397 to 1398 |
|
|
- Date |
July 5 to 9 |
July 5 to 8 |
July 6 to 10 |
- The Plum Creek at Souris decreased 0.15 ft. since yesterday to 1,374.04 ft.
- A flood warning for all reaches of Pipestone Creek and downstream into the Oak and Plum Lake system, then on Plum Creek to the Souris River including the town of Souris remains in effect.
Assiniboine River
- The Assiniboine River forecast, which accounts for the reduced crest seen on the Qu’Appelle River near Welby indicates:
- The forecast peak flow, water level and date of occurrence for locations along the Assiniboine River upstream of the Souris River are depicted in the below table.
|
|
St-Lazare |
Miniota |
Virden |
Griswold |
Brandon at First Street |
|
July Peak |
|||||
|
- Flow (cfs) |
13,000 |
13,000 to 15,000 |
14,000 to 15,000 |
14,000 to 15,000 |
16,000 to 17,000 |
|
- Level (ft.) |
1,288.5 |
1,242.5 to 1,243 |
1,218.5 to 1,219 |
1,201 to 1,201.5 |
1,176.5 to 1,177.5 |
|
- Date |
Crested on June 30 |
July 1 to 3 |
July 1 to 3 |
July 2 to 4 |
July 3 to 5 |
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Inflow upstream of Portage la Prairie is forecast to remain at or near the current flow of
38,000 cfs for the next couple of days before it starts to rise in response to the large flows from the Souris River basin. The inflow into Portage la Prairie is forecasted to reach 48,000 to 52,000 cfs between July 8 to 14, assuming a 2,000 cfs benefit from operating the Shellmouth Reservoir to hold more water. - The lower end of the forecast range was developed for favourable conditions (no further rain) and the upper end of the forecast range was developed for unfavourable conditions, and assumes 15 to 25 mm over saturated soils.
- The Shellmouth Dam outflow is being reduced by approximately 500 cfs daily until July 2 to reach approximately 800 cfs and remain at this level until July 6, when it will begin to rise by approximately 500 cfs per day to return to 3,200 cfs conduit outflow. This operation will reduce the peak flow upstream of Portage la Prairie by 1,500 to 2,000 cfs to accommodate anticipated inflow from the Souris River downstream.
- The Qu’Appelle River crested yesterday at around 9,700 cfs which is earlier and of a lesser amount than the Saskatchewan Watershed Authority’s recent forecast crest of 11,500 cfs to occur tomorrow.
Carrot River
-
Water levels on the Saskatchewan River at The Pas increased 0.15 ft. since yesterday to
856.02 ft., with a flow of 75,400 cfs. The forecast range for The Pas remains at 858 to 859.3 ft. with the peak occurring between July 7 and 12. The water levels are forecast to steadily rise from current levels to reach the forecast peak. The water level stage of 859.3 ft. corresponds to the 100-year flood event for the Saskatchewan River at The Pas. Manitoba Water Stewardship is working closely with the Saskatchewan Watershed Authority to continually update the forecast flows. - The forecast for the Carrot River is still being assessed. At this time, the forecast peak water levels on the Carrot River will still be affected by the peak water level on the Saskatchewan River, from the downstream end of the Carrot River to about mile 18. The forecast peak water levels in that portion of the Carrot River are 859.9 to 861.2 ft., expected to occur between July 7 and 11. Upstream of mile 18 the forecast peak is expected to be somewhat below the spring peak in April.
Lakes
-
A revised forecast was developed for Lake Winnipeg. The wind-eliminated forecast levels for the lakes are as follows and are weather dependant:
- Lake Winnipeg: 717 ft. around mid-July. (Source: Manitoba Hydro)
- Lake Winnipegosis: between 835 and 835.5 ft.
- Lake Pineimuta: between 809.3 and 809.6 ft. around the end of July.
- Lake Manitoba: between 817.7 and 817.8 ft. around the end of July.
- Lake St. Martin: between 806.3 and 806.4 ft. around mid-August.
- Dauphin Lake: between 860.6 and 861.2 ft. around the end of July.
Weather and Wind
-
There is an unstable weather system developing today and tomorrow and may produce up to
50 mm over northeast Saskatchewan and northern Manitoba including The Pas. -
Environment Canada has issued a strong wind warning for Lake Manitoba, Lake Winnipeg and Lake Winnipegosis:
- Lake Manitoba, south 27 km/h in the afternoon, west 27 km/h in the evening. Tomorrow, south 27 km/h in the morning and west 27 km/h in the evening and into Saturday.
- South Basin Lake Winnipeg, south 27 km/h this afternoon, northwest 27 km/h after midnight. Tomorrow northwest 27 km/h, southwest 18 km/h in the afternoon, northwest 37 km/h in the evening, Saturday afternoon, winds becoming light.
- Lake Winnipegosis, south 27 km/h today, west 18 km/h this evening, then northwest 20 km/h tomorrow evening and west 27 km/h on Saturday.
-
Wind set-up today:
- High wind set-up alert for the north shore of Lake Manitoba including Homebrook, Davis Point and St. Martin.
- Moderate wind set-up alert for the west shore and east shore of Lake Manitoba, the northwest shore of Lake St. Martin and the west shore of the South Basin of Lake Winnipeg. This includes communities such as Sandy Bay, Meadow Portage, Crane River, St. Laurent, Lundar Beach, Vogar, the Lake St. Martin First Nation, the Little Saskatchewan First Nation and Gimli.
-
Wind set-up tomorrow:
- Moderate wind set-up alert for the west shore, the east shore, and the north shore of Lake Manitoba, the South Basin of Lake Winnipeg, the northwest shore of Lake St. Martin and the east shore of Oak Lake. This includes Meadow Portage, Crane River, the Ebb and Flow First Nation, Sandy Bay, Lundar Beach, Vogar, Steeprock, Gimli, Chalet Beach, Beaconia, Victoria Beach, Manigotagan, the Little Saskatchewan First Nation, the Lake St. Martin First Nation and Oak Lake Beach.
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.
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