May 08, 2006
Weather
There is a chance of showers and thundershowers this evening into late tomorrow. Precipitation could be significant in the upper Assiniboine area and north to The Pas tomorrow, possibly affecting river and lake levels in that area.
Significant thundershowers with up to 35 mm of rain passed through the southern areas of Winnipeg late yesterday afternoon.
Red River
Levels of the Red River declined nearly three feet from Emerson to the floodway inlet in the 48-hour period ending this morning and are expected to continue to decline quickly.
The Red River is back within its banks at all Manitoba locations.
The Red River level in downtown Winnipeg this morning was 14.9 feet, a decline of about half a foot since Saturday morning. The level is expected to decline to 10 feet by May 17 with favourable weather. The natural level in downtown Winnipeg today without operation of flood control works would have been 17.5 feet and the peak this spring would have been near 28 feet.
The flow in the Red River Floodway this morning was 100 cubic feet per second (cfs) and had reached zero as of noon today. The flow upstream of the floodway inlet was 36,100 cfs.
The floodway operated for 33 days from April 5 to May 8 this spring, which is longer than average. While 2006 produced the fifth-highest spring flood peaks on the Red River this century, the length of operation of the floodway was the seventh longest.
The period of operation is also influenced by rainfall amounts after the flood peak. Rainfall after this year’s flood peak was below average.
Assiniboine River
The water level in Shellmouth Reservoir this morning was 1,411.93 feet, a decline of 0.2 feet in the 48-hour period ending this morning. The reservoir should decline to its spillway elevation of 1,408.5 feet near the end of May based on normal weather conditions. The reservoir inflow was 3,300 cfs and the outflow was 4,350 cfs, all of which was going over the spillway. The reservoir level crested May 3 at 1,412.5 feet with an outflow of 5,500 cfs during a strong north wind.
Flooding of valley lands continues from Shellmouth Dam to Grand Valley west of Brandon. The river crested at St. Lazare this weekend and is expected to crest at Virden on Thursday and at Brandon next Monday. Flooding in the Assiniboine Valley should end May 19 to 23 depending on location, based on favourable weather.
Levels will be close to flood stage at Curran Park in Brandon late next week. Locations east of Brandon to Winnipeg will experience only minor rises with the river remaining well within its banks.
Pembina River
Flooding of agricultural lands will continue for approximately 10 more days in the portion from Rock Lake to Swan Lake where the channel capacity is relatively low.
Souris River
Minor flooding of low-lying agricultural lands continues from the international boundary to near Melita. Levels will continue to decline slowly unless heavy rain develops.
Carrot River
Levels of the Carrot River in Manitoba have declined about one inch in the 48-hour period ending this morning. Minor flooding continues in the portion from the Saskatchewan boundary to 10 miles west of The Pas. Levels are beginning to decline faster in eastern Saskatchewan and this effect will reach Manitoba points later this week unless heavy rain develops.
Flooding of agricultural lands in the Pasquia River Valley near The Pas continues but is steadily diminishing. Manitoba Water Stewardship continues to operate pumps to reduce water levels. Gravity flow through the Napp Dam began about 10 days ago and is aiding the drainage process.
Red Deer River
The level of Red Deer Lake is now declining. The lake has declined about one foot since the crest on April 28 but is still 2.3 feet higher than the 1979 crest.
An updated forecast for the lake based on measured outflows and estimate inflows suggests the lake should decline to 865.5 feet by May 18. This forecast will be updated and further extended later this week. It appears that levels in the community of Red Deer Lake may decline sufficiently for the cleanup to commence in about two weeks time, based on favourable weather. Residents of the community will need to remain relocated in the interim.
For further information, visit http://www.gov.mb.ca/flood.
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