All flood-protection work for up to 350 homes and about a dozen sections of diking along the Assiniboine River should be completed within the next 24 hours, the province said today.
The Assiniboine River crest is expected to arrive at the Portage Diversion on Wednesday between 9 a.m. and noon, reaching a forecasted 50,500 to 51,500 cubic feet per second (cfs) of rain-fed flood water.
To meet that amount, the province will slowly increase flows on the Assiniboine River to 18,000 cfs and 34,000 on the Portage Diversion. Unlike 2011 when the same amount of water flooded the Assiniboine River, the duration of the high flows in the diversion will be relatively short.
Flows are currently 16,950 cfs on the diversion. On the Assiniboine River downstream of the diversion the flow is 15,850 cfs.
Between Portage la Prairie and Headingley, municipal workers, volunteers and about 400 Canadian Armed Forces personnel are sandbagging at-risk homes along the Assiniboine and 150 homes immediately south of the Hoop and Holler Bend southeast of Portage la Prairie on Highway 331.
The province says depending on the stability of its dikes along the Assiniboine — they were originally built about 100 years ago — it may need to make a deliberate cut into Highway 331 to release water from the Assiniboine River. The released floodwater would flow mostly over planted farm fields. A similar action was taken during the 2011 flood.
Where the dikes are the weakest are along tough-to-access areas on the Assiniboine between Poplar Point and St. Francois Xavier.
The province is also raising the east-side dike of the Portage Diversion — the last three kilometres to Lake Manitoba with Aqua Dams — to prevent an overflow of the diversion east towards Delta Beach on Lake Manitoba.
Sunday afternoon, residents of West Delta Beach were advised of a mandatory evacuation order. A precautionary evacuation was also recommended to residents of East Delta Beach.
As of Monday morning, approximately 725 people have evacuated their homes and communities due to flooding so far this year. This includes approximately 160 evacuees from two communities due to spring flooding.
Additionally, 55 municipalities and communities have declared a state of local emergency. New declarations include one from the local government district of Alonsa.
The Assiniboine River at Brandon has now crested at 34,330 cfs with a water level of 1,182.7 ft. with dikes holding. The peak water flow at Brandon during the 2011 flood was 36,730 cfs. A second summer crest on the Assiniboine River at Brandon is expected on July 17 to 18 at 31,000 to 32,000 cfs. This second crest will consist of flows from the upper Assiniboine and Qu’Appelle river basins.
The province also advises of high winds on both Lake Manitoba and Lake Winnipeg today and Tuesday. Both lakes are above their preferred operating ranges because of the flooding. Wind on Lake Winnipeg could increase water levels by two to three feet in the south basin. Wind on Lake Manitoba could increase water levels by up to one foot in the south basin of the lake along with considerable wave action on shorelines.