Flows on the Assiniboine River are increasing as water moves through the system.
From the Shellmouth Dam to St-Lazare, these flows will be the peak flow on the river. However, from Miniota to Brandon, these flows are a second crest which will be slightly smaller than the crest which moved through earlier this week.
The difference in size between the two crests is largely due to declining tributary flows as the water moves down the river.
The second crest is expected to be sustained over a few days, longer than the first crest.
Existing flood protection along the Assiniboine River is expected to be adequate for the forecast second crest.
This crest is close to St-Lazare and is expected to be between 27,500 and 29,000 cubic feet per second (cfs). These peak flows are expected to last for a day or two around July 10.
The second crest on the Assiniboine River at Miniota is expected to be between 31,000 and 32,800 cfs. These peak flows are expected to last for a day or two around July 10.
The second crest on the Assiniboine River at Brandon is expected to be between 31,800 and 33,900 cfs. These peak flows are expected to last for a day or two between July 12 and 14.
Portage Diversion Update
Flows on the first crest on the Assiniboine River at the Portage Reservoir are nearly crest and early this evening the river was measured at 51,900 cfs. Flows on the Portage Diversion are approximately 33,900 cfs and flow on the Assiniboine River immediately downstream of the diversion is 18,000 cfs.
The flow on the Assiniboine River below the diversion was increased to 18,000 cfs yesterday at midnight. Current flows at Baie St. Paul are 16,300 cfs. Flows of 18,000 cfs will reach
Baie St. Paul by approximately midnight tonight.
Water levels along the dikes are expected to stay at 18,000 cfs for several days.
Flows of 51,500 cfs over one minute are approximately equal to the amount of water in
35 Olympic-sized pools per minute.
Work to prepare for the high flows on the lower Assiniboine River has been completed and the condition of the Portage Diversion, lower Assiniboine River dikes and temporary flood protection measures downstream will continue to be monitored regularly.
The province is working directly with municipalities to address flooding issues. Crews are on call to respond to trouble spots.