May 11, 2009
Flood Media Bulletin #40
Weather Conditions
· Showers tomorrow evening to Wednesday afternoon with a possible thundershower late tomorrow may result in rainfall amounts of 10 to 25 millimetres (0.4 to one inch) over southeastern Manitoba including Winnipeg and the Riding Mountain and Dauphin areas.
City of Winnipeg
· The Red River level at James Avenue in Winnipeg this morning was 5.25 m (17.24 ft.), a rise of 1.27 centimetres, (0.5 in.) since yesterday morning. The minor rise resulted from lowering of the control gates at St. Norbert which offset declining flows on the Assiniboine River. Fluctuations of up to three cm (1.2 in.) from the general trend in the city river levels may occur during the next few weeks due to operation of flood control works.
· With river levels just below 5.18 m (17 ft.), there is a significant risk of basement flooding due to sewer backup in vulnerable areas of Winnipeg due to rain in the forecast. The extent of possible basement flooding depends on the intensity of the rain. The Portage Diversion has been used to reduce flows on the Assiniboine River as much as possible to lower river levels in Winnipeg in order to reduce the potential for such problems.
· The level in downtown Winnipeg will decline below 5.18 m (17 ft.) by tomorrow and will be in the range of five to 5.2 m (16.4 to 16.9 ft.) for the most of this week. As of this morning, the level at James Avenue has declined 1.6 m (5.25 ft.) from the April 16 crest.
· The level in Winnipeg will continue to gradually decline for the next few weeks. It is unlikely the rain predicted for the next few days will cause an increase in levels since declining flows on the Assiniboine will more than offset the rain and lowering of the gates at St. Norbert.
Emerson to St. Adolphe
· The river level from Morris to St. Adolphe declined by more than 0.23 m (0.75 ft.) since yesterday morning, while levels from Emerson to St. Jean Baptiste fell by less than 0.15 m (0.5 ft.). Significant declines will continue, although not quite as quickly, for the next few days.
· The total decline in river levels since the crest ranged from 1.5 m (five ft.) at Emerson and St. Adolphe to 1.8 m (six ft.) at Morris.
· The level at Morris is still expected to decline to the PTH 75 elevation by late Tuesday or Wednesday.
Floodway Inlet
· The floodway gates will continue to be operated as required to maintain levels somewhat below natural levels upstream at the floodway inlet. A gradual lowering of the control gates will continue.
· The water level upstream of the floodway inlet this morning was 231.87 m (760.73 ft.), a decline of 0.27 m (0.9 ft.) since yesterday morning. The large decline was in part due to lowering of the control gates. The flow into the Red River Floodway this morning was 22,070 cubic feet per second (cfs) of a total 70,450 cfs upstream of the floodway inlet.
· The level at the floodway inlet is expected to decline to 231.65 m (760 ft.) by late tomorrow or early Wednesday. This is the elevation at which St. Mary’s Road (PR 200) is no longer flooded.
Lockport to Breezy Point
· Levels from Lockport to Breezy Point will continue to decline 6.1 to 12.2 cm (2.4 to 4.8 in.) per day although significant fluctuation will occur depending on changes in wind speed and direction due to backwater from Lake Winnipeg.
Assiniboine River
· Flow into the Portage Reservoir decreased to 8,900 cfs this morning from 9,230 cfs yesterday morning. The inflow will continue to decline for the next few weeks unless heavy rain develops. The flow in the Portage Diversion this morning was 8,415 cfs while the flow in the river downstream was 485 cfs.
· River flows toward Winnipeg were decreased to 500 cfs on May 9 in order to lower river levels in Winnipeg for the anticipated rain tomorrow night to Wednesday. Assiniboine River flows had begun to decrease at Winnipeg this morning.
· The Shellmouth Reservoir water level rose 3.6 cm (1.4 in.) since yesterday morning and stood at 427 m (1,403.9 ft.) this morning. The outflow was to be increased to 800 cfs early this afternoon from 100 cfs in order to minimize further rises on the reservoir. The downstream bank-full capacity is 1,600 cfs. The reservoir level is unlikely to rise past 428 m (1,404.3 ft.) based on this increase in the outflow. The spillway level is 429.3 m (1,408.5 ft.).
Souris River
· Levels of the Souris River continue to decline slowly from the crests observed in late April to early May. The level at Melita has declined by 0.3 m (one ft.) from the crest. At Souris and Wawanesa the level has declined less than 0.15 m (0.5 ft.).
· Levels on the Souris River will begin to decline more rapidly next week unless significant rainfall develops.
· There are still some over-bank flows from just north Significant over-bank flooding continues from the U.S. boundary to just south of Melita. Based on favourable weather, by late May, flooding should be limited to a small area.
· There are still some over-bank flows just north of Melita to near the town of Souris. Flooding in this portion should end by next weekend unless heavy precipitation develops.
· The duration of flooding will be significantly shorter than in 1999.
Pembina River
· Flooding of the Pembina Valley continues from Rock Lake to near Windygates although levels are declining about 3.1 cm (1.2 in.) per day. A very gradual decline in levels will continue unless significant rain develops. Flooding between Rock Lake and Swan Lake is expected to continue for another three weeks while flooding of most valley lands in the La Rivière area should end this week.
· Rock Lake is presently at 406.9 m (1,335 ft.) and will continue to decline slowly based on favourable weather. While the level remains high, there is no serious shoreline flooding at this time. The normal summer level is near 405.4 m (1,330 ft.).
· The level of Pelican Lake was estimated at 412.1 m (1,351.95 ft.) this morning. The outlet control works continue to be operated to reduce the lake to its desirable level of 412 m (1,351.7 ft.). Unless rainfall is heavy, the target level should be reached by the end of this week.
· The Pembina River at La Rivière has declined 1.6 m (5.2 ft.) from its April 18 crest and the level at Neche has declined 2.3 m (7.6 ft.) from its April 21 crest.
Lakes
· Satellite images show the ice on Lake Manitoba and on Lake Winnipeg south of the Narrows is beginning to break up. Much of the ice is now free to move with the winds. Ice may push up the shoreline in areas of shallow slopes such as at beaches if strong on-shore winds develop. Those who have experienced difficulties due to ice before are advised to take whatever precautions may be feasible, such as moving valuables to higher ground. The ice will likely be melted by the end of this week.
· The level of Lake Winnipeg is presently near 217.9 m (714.9 ft.). The lake is regulated within the range of 216.7 to 217.9 m (711 to 715 ft.). Manitoba Hydro is releasing maximum outflows to reduce additional rises, but the lake is still expected to rise to near 217.9 m (715 ft.) later in May.
· The level of Lake Manitoba is presently at 247.67 m (812.55 ft.) and is expected to crest near 247.7 m (812.65 ft.) later in May. The lake is regulated within the range of 247 to 247.7 m (810.5 to 812.5 ft.). The outflow from the lake is presently near 8,500 cfs and cannot be significantly increased without causing flooding on Lake St. Martin, which is presently at 244.1 m (801.05 ft.) or about 0.15 m (0.5 ft.) below flood stage. Lake St. Martin is expected to crest at 244.3 m (801.5 ft.) in early June. Fairford Dam has not been operated since Feb. 6 in accordance with the present rules of operation.
· The level of Dauphin Lake is near 261 m (856.35 ft.), a good level for this time of year. No significant further rise is expected unless heavy rain develops.
· Most lakes in the Whiteshell are still well above their summer target levels but have begun to decline slowly.
· Further details and specific forecasted crest stages are shown on daily flood sheets issued by Manitoba Water Stewardship. This information may be viewed at:
Flood Response
· The flood water has just receded enough to see the bridge deck over the Morris River at Morris. Inspection of this and other key areas of PTH 75 will occur as soon as possible and, unless significant repair issues are needed, this main route north and south of Winnipeg will likely be ready to reopen to the U.S. border on Friday. Meanwhile, crews have continued to restore damaged shoulders and remove debris on various portions of PTH 75. Check highway conditions before travelling at www.manitoba.ca, 204-945-3704 or 1‑877‑627‑6237.
· The dike closure on PTH 23 at Morris has been taken down and the dike on the south side of Morris was being taken down today. The dike on the north side of Morris remains in place.
· Residents in areas affected by flooding who use well water must boil water before drinking it or use a safe alternative such as bottled water until test results confirm the bacterial safety of their water. Sampling of well water should begin after the flood water has subsided. The province will cover all costs of bacterial water testing for a period of three months after the flood waters recede.
· The public may contact Manitoba Government Inquiry at 1-866-626-4862 (toll-free), Monday through Friday from 8 a.m. to 4:30 p.m. After-hours flood issues should be directed to local municipal offices.
Flood information is available at www.manitoba.ca.
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