August 16, 2010
Flood Watch Ended for Northern Interlake, Lake Winnipeg Regions; Flood Warning Lifted for Assiniboine River Valley
Interlake and Lake Winnipeg Regions
· A flood watch has been lifted for portions of the north Interlake area and eastern parts of Lake Winnipeg including Fisher River, Arborg, Hecla, Gypsumville, Ashern, Poplar River and Bloodvein.
· Although these areas received substantial rainfall amounts over the past three days, the rain has now tapered off. Rainfall amounts as high as 90 millimetres (3.5 inches) were reported and significant water level increases were reported in some streams and Lake Winnipeg, but no major flooding was reported.
· In the last 24 hours, Grand Rapids has received only 11 mm (0.43 in.), while Fisher Branch had
10 mm (0.39 in.) of rainfall.
10 mm (0.39 in.) of rainfall.
· As of this morning, the Bloodvein and Fisher rivers and Netley Creek had all risen by 0.5, 0.45 and 0.3 metres (1.8, 1.5, and one feet) respectively since Friday. The water level rises are slowing down and with favourable weather the rivers will be cresting in the next three days.
· Unstable weather over Lake Winnipeg has weakened greatly and little or no rain is expected in the north Interlake and Lake Winnipeg areas.
· On average, Lake Winnipeg had risen by more than 15 centimetres (0.5 ft.) between Friday and Sunday morning due local inflows from the weekend rains. In the last 24 hours, the level has declined by less than 15 cm (0.5 ft.) to a level of 218 m (716.04 ft.). With favourable weather, the lake will remain close to its crest level and will recede very gradually in the coming days.
Assiniboine River and Shellmouth Reservoir Operation
· Water levels continue to decline significantly and flows are generally within the river bank. A few low-lying areas and those immediately downstream of the reservoir continue to have water levels close to bankfull elevations but are declining with favourable weather. The weather forecast calls for a chance of rain later this afternoon and tomorrow for portions of southern Manitoba. However, the amounts are expected to be minimal. The Assiniboine River levels and its tributaries will see significant decline in the next few days under the forecasted weather.
· The Shellmouth Reservoir level has declined by four cm (0.13 ft.) to 429.8 m (1,410.33 ft.) since yesterday. The computed inflow this morning was 1,215 cubic feet per second (cfs). The spillway flow was 1,550 cfs, compared to 1,650 cfs yesterday.
· The conduit will be operated this afternoon to maintain a total reservoir outflow of about 1,600 cfs.
Dams and Lakes
· The average Lake Manitoba level was 247.6 m (812.34 ft.) this morning and the lake is returning to the level it was at before the storms of last weekend (Friday’s level was 812.3 ft.). Lake Winnipegosis average level was 254 m (833.33 ft.), a rise of about 20.23 cm (0.2 ft.) since last Friday. Dauphin Lake average level is 261.1 m (856.79 ft.) today, a drop of about 15 cm
(0.5 ft.) since Friday. The Whiteshell lakes levels continue to be higher than normal this summer, and operations of dams in the area is done when necessary to reduce levels to summer target
(0.5 ft.) since Friday. The Whiteshell lakes levels continue to be higher than normal this summer, and operations of dams in the area is done when necessary to reduce levels to summer target
Graphical information on lakes levels is updated regularly and posted at:
Additional information can be found at www.gov.mb.ca/waterstewardship/floodinfo/index.html.
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