Manitoba Water Stewardship

FLOOD UPDATE FOR MANITOBA

April 29, 2006.

Crest at Shellmouth Reservoir Expected Early Next Week

Red Deer Lake Begins a Slow Decline

Flood sheets showing present conditions and an updated forecast for: Red River, Pembina River, Assiniboine River and Swan River - The Pas Area are attached.

Weather

Unsettled weather with scattered showers is expected over southeastern Manitoba for the next five days. Some rain is likely to develop in western Manitoba next Tuesday to Wednesday. Rainfall amounts are expected to be relatively light and unlikely to affect river levels significantly.

Red River

Levels of the Red River declined at least three-quarters of a foot from Emerson to the Floodway Inlet during the 24 hour period ending this morning. Levels will continue to decline a little faster day by day based on little precipitation.

As a result of dry weather and relatively rapid river declines this week, PTH 75 re-opened at Morris late yesterday afternoon. The highway had been closed to traffic just north of Morris since April 10.

The Red River level in downtown Winnipeg this morning was 17.5 feet, a decline of 0.17 feet since yesterday and a decline of about 2.8 feet since the crest of April 7. Levels in the city will continue to decline very slowly based on favourable weather. The natural level in downtown Winnipeg today without operation of flood control works would have been 24.7 feet.

The flow in the Red River Floodway this morning was 21,600 cubic feet per second (cfs) while the flow upstream of the floodway inlet was 67,700 cfs. The peak floodway flow in 1997 was 66,000 cfs.

Assiniboine River

The Assiniboine River is still within its banks from Oak Lake to Winnipeg due to operation of flood control works. Extensive flooding of valley lands continues from Shellmouth Dam to Millwood and minor overbank flows are occurring from St. Lazare to Virden. Levels from Miniota to Virden have been relatively steady in recent days but will begin to rise again in a few days as higher flows arrive from the Shellmouth area. Increases in river levels will spread downstream to Oak Lake and Brandon early next week, causing a shallow inundation of agricultural lands in the river valley. Flooding from St. Lazare to Grand Valley should end by mid May with normal weather conditions.

Flooding from Shellmouth to Millwood will more extensive than at downstream points and will likely last longer due to the smaller channel capacity.

The water level in Shellmouth Reservoir this morning was 1411.74 feet, which is 3.2 feet above the spillway elevation. The reservoir inflow was 7400 cfs, a decline of 1200 cfs from yesterday morning. The total outflow was 5,000 cfs, of which 4000 cfs was going over the spillway. Flow through the conduit was further reduced this morning to maintain a total outflow of 5,000 cfs. The reservoir water level is expected to crest at 1412.3 feet on May 2 based on little precipitation for the next 10 days.

Manitoba Water Stewardship, in consultation with the Shellmouth Reservoir Regulation Liaison Committee, is operating the reservoir to minimize the peak outflow. Controlled conduit outflows will be reduced day by day to maintain a total outflow of 5,000 cfs or less if possible. Reservoir and river conditions as well as forecasts are being updated every day.

Flooding is not expected in Brandon with the possible exception of low lying areas at Curren Park. Locations from Brandon to Winnipeg will experience only minor rises as the river remains well within the banks.

The flow in the Portage Diversion this morning was 3,830 cfs while the inflow to Portage Reservoir was near 9000 cfs.

Flooding of low-lying agricultural lands along the Shell River will continue for another week or so even with favourable weather.

Pembina River

Significant flooding continues on the Pembina River from Rock Lake to Swan Lake, but levels continue to decline.

Water levels at Gretna and at the Aux Marais crossing at the international boundary fell about half a foot since yesterday. The United States National Weather Service is expecting the level to decline a further 1.6 feet at Neche by May 5.

Carrot and Saskatchewan Rivers

The level of the Saskatchewan River at The Pas continues to decline very slowly and no further rise is expected with favourable weather.

Levels of the Carrot River from the Saskatchewan boundary to 12 miles west The Pas rose less than an inch at most points since yesterday. Very little further rise is expected as the river is essentially at its crest now. Minor flooding has developed in this portion of the river, where levels will remain high for the next three weeks. Levels within 5 miles of The Pas should continue to decline slowly based on little precipitation.

Extensive flooding of agricultural lands in the Pasquia River Valley near The Pas continues with levels in some areas as high as those of the flood last autumn. Pumping to reduce water levels continues at maximum capacity.

Red Deer River

The Red Deer River crested early this week in the Manitoba portion upstream of Red Deer Lake. Long-term residents say that this flood is greater than that of 1955. The possibility of record flooding on the Red Deer River was mentioned in the March, 2006 flood outlook issued by Manitoba Water Stewardship.

The level of Red Deer Lake has just begun a very slow decline from a record crest 3.1 feet higher than that of 1979. The Lake fell about one-third of an inch since yesterday. Residents of the community of Red Deer Lake will need to remain relocated for a considerable period of time since it will take at least three weeks before levels decline sufficiently for the clean-up to commence.

Hydrologic Forecast Centre,
Water Branch,
Manitoba Water Stewardship

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Water Information

FLOOD UPDATE FOR MANITOBA