FLOOD REPORT FOR MANITOBA. June 28, A Gale wind warning is in effect for Lake Manitoba and Lake Winnipeg

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1 FLOOD REPORT FOR MANITOBA June 28, 2014 A Gale wind warning is in effect for Lake Manitoba and Lake Winnipeg Flood Warning*: Flood Watch*: High Water Advisory*: - Assiniboine River, from Shellmouth Dam to Brandon (due to high flows) - All points along the Winnipeg River System, including Nutimik Lake - Lake St. Martin - Dauphin Lake - Lake Manitoba - Lake Winnipeg - All points along the Red River - All points along the Saskatchewan River Summary Environment Canada has issued a gale wind warning for Lake Manitoba, the north and south basins of Lake Winnipeg, and Lake of the Woods. o On Lake Manitoba, light winds this morning will increase to east winds at 40 km/hour this afternoon, and shift to southwest at 55 km/hour overnight. o On Lake Winnipeg, light winds this morning will increase to southeast at 40 km/hour this afternoon, and shift to south winds at 55 km/hour overnight. o Strong winds are also expected on Monday and Tuesday but will shift to come out of the west to northwest. For more information: Manitoba Infrastructure and Transportation s Hydrologic Forecast Centre reports the lake wind-effect forecast for tomorrow suggests a high to severe wind warning for Lake Manitoba and Lake Winnipeg. The south-southwest winds could increase water levels and result in significant wave action on north and east shorelines of the lake (see attached map for illustration of forecasted wind effect on lakes). Environment Canada has issued a rainfall warning for much of western Manitoba: A slow moving low pressure system will move into southwestern Manitoba this afternoon and will intensify tonight. Precipitation associated with this weather system spread into southwestern Manitoba and the extreme southeastern corner of Saskatchewan this morning. The area is expected to move into the Parklands area of Manitoba this afternoon and east central Saskatchewan tonight. Rain will intensify tonight and continue Sunday. General rainfall amounts around 50 mm

2 are expected. The Dauphin, Minnedosa, Yorkton and Kamsack regions will see 50 to 75 mm of rain. Weather conditions will begin to improve Sunday night. Heavy downpours can cause flash floods and water pooling on roads. Localized flooding in low-lying areas is possible. Watch for possible washouts near rivers, creeks and culverts. Source: Weather The storm system yesterday brought significant rainfall to parts of western Manitoba, with Brandon receiving 51 mm, Dauphin 28 mm, Carberry, 38mm, and Melita 15 mm. Winnipeg received 11 mm, and Gimli received 24 mm. Rainfall for Saturday and Sunday will be heaviest in western Manitoba, with general rainfall amounts of 50 mm expected, the areas Dauphin, Roblin and Minnedosa could receive up to 75 mm. Further east, by end of day Sunday, Winnipeg is expected to receive mm, the Interlake is expected to receive mm, and eastern Manitoba approximately 25mm. Red River The Red River is rising at all points in Manitoba from Winnipeg upstream. The Red River at James Avenue in downtown Winnipeg is at 16 feet and is forecasted to go up to 16.7 feet in the next week. The river is forecasted to stay above 14 feet until mid July. There is the potential that the Red River Floodway could be operated under Rule 4, to reduce the risk of basement flooding damages within Winnipeg, depending on weather conditions. Assiniboine River The water level on the Shellmouth Reservoir has increased to 1,410.4 feet; the summer target level is feet and the crest of the spillway is at feet. As the water level has exceeded the spillway crest elevation, flows are occurring over the spillway; spillway flows will increase or decrease as the reservoir level rises and falls. Inflows to the reservoir are approximately 3,430 cfs today; outflows from the reservoir are approximately 2,650 cfs. Outflows include 1,050 cfs of conduit flow and 1,600 cfs of spillway flow. The Portage Diversion is not in operation. Flow on the Assiniboine River upstream of the Portage Diversion is 9,450 cfs. The Portage Diversion will be operated if required to maintain 10,500 cfs along the lower Assiniboine River. Weather conditions in the Assiniboine River basin will determine if and when the Portage Diversion will be operated. The recorded precipitation and short-term weather forecasts are being analyzed to produce a new forecast for the Assiniboine River. 2

3 Parkland Region Dauphin Lake is at feet and is forecasted to peak at to ft by mid-july. The flood stage on the lake is 858 feet and the summer target level is 855 feet. Figure 1: Dauphin Lake Forecasted Water Levels Manitoba Lakes Lake Manitoba is presently at approximately feet and is forecasted to peak in early July at approximately feet with normal weather, or at approximately feet if wetter conditions persist. Lake Manitoba is currently approximately 1.8 feet below unregulated levels (the levels that would have occurred in the absence of all provincial water control infrastructure) because of the high outflows out of the Lake through the Fairford River Water Control Structure. The actual outflows have been higher than what the natural outflows would have been for all of 2014, and also in previous years. The Fairford River Water Control Structure is being operated for maximum possible discharge; outflow from Lake Manitoba is approximately 13,270 cfs. The estimated natural outflow from Lake Manitoba at the current lake level, if the Fairford River Water Control Structure and associated channel improvements hadn t been constructed, is approximately 4,500 cfs. The Lake St. Martin gauge is registering a water level reading of feet. The windeliminated lake level is forecasted to peak just above 803 feet. 3

4 Work to re-open the Lake St. Martin Emergency Outlet Channel will begin July 2. Operation of the Lake St. Martin Emergency Channel will increase outflow from Lake St. Martin, directly lowering levels, and allow the Fairford River Water Control Structure to remain at maximum discharge longer, thus allowing for higher outflows from Lake Manitoba later in the year. The initial discharge through the Lake St. Martin Emergency Outlet Channel will be approximately 5,600 cfs. The channel is expected to stay open until the spring of 2015, and will help bring the Lake St. Martin water level below 801 feet by October 31, Lake Winnipeg is at feet, and Manitoba Hydro forecasts that it will rise to approximately feet by late July. The water level regulation range for Lake Winnipeg is between 711 and 715 feet. Manitoba Hydro is operating its structures at the outlet of Lake Winnipeg to allow for maximum possible outflow from the lake. Eastern Region The Winnipeg River system is experiencing very high flows due to significantly higher than normal precipitation in eastern Manitoba and northern-western Ontario. Nutimik Lake, which is part of the Winnipeg River system, is at 908.3feet, a record high level on the lake. Dorothy and Eleanor Lakes, which are downstream from Nutimik Lake, are also experienced high water levels and some overland flooding. There are reports of boat houses being flooded and some sandbagging is underway. The Lake of the Woods Control Board has indicated that Nutimik Lake could rise by an additional foot by mid- July, depending on weather conditions. The Pas and Northern Manitoba The flow on the Saskatchewan River at The Pas is at 60,990 cfs. Saskatchewan River flows at The Pas are forecasted to peak on July 10 at 63,000 cfs, which is approximately 10,000 cfs lower than the open water crest this past spring. Cormorant Lake is at feet and is forecasted to rise by another 0.5 feet due to the forecasted rainfall. Wind setup and wave action on the lake is forecasted from 0.3 to 1.5 feet, depending on wind speed and direction. *Definitions Flood Warning: A flood warning is issued when river or lake levels are exceeding or are expected to be exceeding flood stage within the next 24 hours. Flood Watch: A flood watch is issued when river or lake levels are approaching and likely to reach flood stage, but likely not within the next 24 hours. High Water Advisory: A high water advisory is issued when a heavy storm or high flows are expected and may cause water levels to rise, but not necessarily reach flood stage. A high water advisory can be an early indicator for conditions that may develop into a flood watch or flood warning. 4

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