March 23, 2010
Dry Weather Reduces Red River Flood Potential
– – –Predicted Crests Lowered For Red River in Manitoba
The latest report from Manitoba Water Stewardship’s Hydrologic Forecast Centre indicates southern Manitoba is benefiting from a slow melt and dry weather, with levels of predicted Red River crests now being lowered. While possible adverse weather over the next few weeks could still be a factor, this risk is diminishing as the crest nears.
A reduced crest coming from the United States and minor early flows from Manitoba tributaries will contribute to lower Red River crests in Manitoba.
Red River
· Levels of the Red River continue to rise from Drayton, N.D., to Lake Winnipeg. Increases in the past 24 hours range from just over 0.6 metres (two feet) at Emerson, 0.3 m (one ft.) at St. Adolphe and 0.15 m (0.5 ft.) at Selkirk. The level at James Avenue in downtown Winnipeg rose 0.2 m
(0.7 ft.) to 4.8 m (15.8 ft.). The river is still within its banks, except at St. Jean Baptiste where minor overbank flows have begun.
(0.7 ft.) to 4.8 m (15.8 ft.). The river is still within its banks, except at St. Jean Baptiste where minor overbank flows have begun.
· Predicted crests for Manitoba have been revised downward by 0.6 m (two ft.) from Letellier to
Ste. Agathe and 0.9 m (three ft.) from St. Adolphe to the Floodway Inlet. Crests at Emerson and also north of Winnipeg have been reduced by about 0.3 m (one ft.). The crest reductions are due to favourable factors such as a lower-flow crest coming from the U.S., and Manitoba tributaries cresting well ahead of the crest at Emerson. Continued dry weather and an early, gradual melt have been significant factors reducing run-off. It is possible that adverse weather, over the next few weeks, could still be a factor but this risk is diminishing as the crest nears.
Ste. Agathe and 0.9 m (three ft.) from St. Adolphe to the Floodway Inlet. Crests at Emerson and also north of Winnipeg have been reduced by about 0.3 m (one ft.). The crest reductions are due to favourable factors such as a lower-flow crest coming from the U.S., and Manitoba tributaries cresting well ahead of the crest at Emerson. Continued dry weather and an early, gradual melt have been significant factors reducing run-off. It is possible that adverse weather, over the next few weeks, could still be a factor but this risk is diminishing as the crest nears.
· The crest in downtown Winnipeg is expected between 5.3 and 5.8 m (17.5 and 19 ft.).
· The crest is expected at Emerson March 30 to 31, at Morris April 4, in the Winnipeg area April 7
to 8 and at Selkirk about April 9.
to 8 and at Selkirk about April 9.
· Significant over-bank flooding is still expected from Letellier to Morris, along the Morris River from Brunkild to Morris and also along the Marsh River. Some flooding is expected from St. Adolphe to the Floodway Inlet. However, with levels 0.9 to 1.5 m (three to five ft.) lower than in 2009, depending on location, flooding will be much less extensive than in 2009.
· There has been no significant ice jamming along the Red from Lockport to Breezy Point so far. Serious ice jams are unlikely this spring due to ice-cutting and icebreaking and due to relatively weak ice.
· Operation of the Red River Floodway is likely to begin March 25 to 26.
Assiniboine River
· River rises have been minimal. Levels at Brandon rose only three centimetres (0.1 ft.) in the past 24 hours. The river will be well within its banks this spring based on normal weather.
· Operation of the Portage Diversion may not be necessary this spring, due to the low river flows.
· The level of Shellmouth Reservoir will be well-below normal summer levels this spring if the dry weather continues.
Souris and Pembina Rivers
· Levels of the Souris River are unchanged in the past 24 hours. Minor rises will develop at Coulter and Melita during the next few days due to a recent release of 400 cubic feet per second from the J. Clark Salyer refuges in North Dakota. There will be only minor flooding in the Coulter area with normal weather.
· Levels of the Pembina River are rising very slowly. Rock Lake rose three cm (0.1 ft.) in the past 24 hours and is at 405.4 m (1,330.2 ft.). There is no threat of flooding unless heavy rain develops.
Interlake and Whiteshell
· Run-off is much-below average with no threat of flooding. Logs will be placed at dams on Whiteshell-area lakes to help raise lakes up to summer levels.
Westlake Area
· Run-off in the lowlands is virtually complete with no flooding problems. There should be few problems based on normal spring weather.
The full report is available at www.manitoba.ca.
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