The Saskatchewan Watershed Authority will conduct a two-day test of the Fishing Lake channel in the upper Assiniboine River basin next week. Fishing Lake water flows into the Whitesand River, the Assiniboine River in Saskatchewan and into the cross-boundary Lake of the Prairies and the Shellmouth Reservoir.
The Good Spirit Lake Watershed Association has agreed to reduce outflows for a four-day period to offset the additional release through the Fishing Lake channel. The authority will be overseeing the operation and will match the reduction in flow from the lake as closely as possible to the increase in outflow from Fishing Lake as a result of the test. Since the Good Spirit reduction operation will be over a four-day period and the Fishing Lake increased operation will be over a two-day period, there will be a net reduction in the flow contribution to the Assiniboine River as a result of these operations.
Dozens of trucks and excavators are working on a significant dike-construction project raising existing dikes and building new ones along about 16 kilometres of the Saskatchewan River near The Pas and Ralls Island. This will provide one-in-100-year water level protection. Eleven people in the area have lost safe access to their homes as a result of the construction. Residents along the Carrot River have been working on building approximately 6.4 km of dikes to provide flood protection to their homes.
Additional evacuations have occurred from the RM of Siglunes and the Lake Manitoba First Nation. At this time, 2,632 Manitobans are evacuated from their homes.
Residents along Skinny Dip Bay in Siglunes have limited daytime access to their properties and there is still no access at Kernstead Beach.
Manitoba Conservation has deployed three, five-member rapid assistance teams to the RM of Coldwell to assist with sandbagging and dike construction efforts in the area.
Flood Forecast
A weather system brought precipitation to parts of Manitoba and Saskatchewan yesterday. In Manitoba, the Souris area received 27 millimetres, Roblin 0.6 mm, and trace amounts in The Pas. In Saskatchewan, the Estevan area received 31.4 mm, Prince Albert 13 mm, Melfort 19.5 mm, Fort Qu’Appelle 56.8 mm, Preeceville 35 mm and Ivermay 39 mm.
Rainfall across the Prairie provinces for the month of June to date, as a per cent of normal precipitation for locations in Alberta, Saskatchewan and Manitoba: Edmonton, 121.12 per cent (76.4 mm); Regina, 164.8 per cent (82.55 mm); Weyburn, 323.87 per cent (157.4 mm); Prince Albert, 174.79 per cent (84.6 mm); and Brandon, 215.3 per cent (106.8 mm).
There is an unstable weather system developing today and tomorrow generally bringing up to 10 mm of rain with localized cells bringing up to 20 mm over northern Alberta, most of Saskatchewan, southeast Manitoba and western North Dakota, and up to 50 mm along the east edge of North Dakota in the Red River Basin.
Water levels on the Saskatchewan River at The Pas increased 0.08 feet since yesterday to 854.54 ft., with a flow of 66,800 cubic feet per second (cfs). In response to recent rainfall in Saskatchewan, reservoirs along the Saskatchewan River are nearing capacity. Peak flows in the order of 123,600 cfs are now anticipated downstream of Tobin Lake. The preliminary forecast range for The Pas is from 858 to 859.3 ft. 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.
Lakes
A revised forecast was developed for Lake Winnipeg due to increased flows on the Saskatchewan River in response to recent rainfall events and is weather dependent. It will be 717.1 ft. around the end of July. (Source: Manitoba Hydro)
Assiniboine River
The forecast for the Assiniboine River is being assessed due to recent rainfall events. The upper Assiniboine River has not received as much rainfall as the Souris River or Saskatchewan River basins and the Shellmouth Reservoir inflows are not expected to be significantly impacted.
Inflow upstream of Portage la Prairie is 43,900 cfs. Flows in the Portage Diversion channel are 25,980 cfs. Flows on the Assiniboine River at the Portage Reservoir control gates are 17,920 cfs. Inflow upstream of Portage la Prairie is forecast to continue to decline to approximately 43,000 cfs by tomorrow, and then begin a more gradual decline.
Souris River
Some areas of the Saskatchewan portion of the Souris River basin have received heavy rainfall with cumulative amounts ranging between 34 and 127 mm over the last week, with a further five to 10 mm forecast for Friday and Saturday. Outflows from the Rafferty and Alameda reservoirs were increased, which will affect flows on the Souris River.
The Rafferty Reservoir water level has been slowly declining and is currently slightly below the maximum allowable flood level with an outflow between 15,000 to 15,500 cfs. The Saskatchewan Watershed Authority opened the spillway gates fully yesterday as there were concerns the additional inflow from Sunday’s rainfall might exceed the spillway capacity of 20,500 cfs.
The Alameda and Boundary reservoirs outflows were increased in response to recent rainfall, although not to the extent of the Rafferty Reservoir.
The forecast rainfall in Saskatchewan is being assessed to be able to provide a revised forecast for the Souris River in Manitoba. Manitoba Water Stewardship is working closely with the U.S. National Weather Service and the Saskatchewan Watershed Authority on this issue. Preliminary forecasts show the Souris River cresting in mid-July near the spring peak level and remaining at that level for an extended period of time. Precipitation during the next three weeks will be very critical.
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.
