Condition Reports

High Water Conditions and Control Structure Operations for Southern Manitoba

August 3, 2007

Table of Contents:

• Highlights

Highlights

There are no high water advisories or warnings in effect at this time.  However unusually high levels continue on Lake Winnipegosis, Lake Winnipeg. Lake Manitoba, Lake St. Martin, some lakes on the Nelson River, some lakes near The Pas, and on the Waterhen, Fairford and Dauphin rivers.

 

Water Supplies:

Water supplies in Manitoba’s rivers, lakes, reservoirs and aquifers are at near optimum conditions as of early August, 2007 and are likely to remain in good condition for the rest of the year. This is largely due to a good spring recharge and additional runoff from well above average rainfall from mid May to early July. Most reservoirs are close to full and aquifers are at average or above average levels. River flows are generally above average although declining quite rapidly due to dry weather in recent weeks.

Lakes Levels:

The level of Lake Winnipeg is 714.9 feet, just below the top of the operating range.

The level of Lake Manitoba is 812.5 feet, which is at the top of the operating range.

Lake Winnipegosis is at 833.55 feet which is the highest summer level since 1955.

Most lakes in Manitoba have declined during the past few weeks due to hot, dry weather. Since evaporation is now entering its annual high period, lake levels are likely to decline further during the next few months. However with lakes presently at or above average levels, it is unlikely that unusually low levels will develop this year.

Levels of most lakes in the Whiteshell area have declined to their summer target levels. Logs have been placed at most controlled lakes during the past 10 days to prevent lakes from declining below the desirable levels. Falcon Lake is still above the target level due to restricted outflows resulting from vegetation and beaver dams in the Falcon River. Lakes on the Winnipeg River are at near normal summer levels.

A more comprehensive lake report was issued on July 20, 2007 and is on the Water Stewardship Website

http://www.gov.mb.ca/waterstewardship/index.html?index.html

River Conditions:

Flows in virtually all rivers are at above average as of early August. However flows and levels on most rivers have declined significantly in recent weeks due to hot dry weather.

Flows continue to be unusually high on the Nelson River, Assiniboine River, Pembina River, Waterhen River, Fairford River and Dauphin River.

Flows on the Souris River are below average but well above the lower decile condition. Present releases from North Dakota are 60 cfs which is well above the minimum requirement of 20 cfs during the summer period.   

Flows on the Winnipeg River have recovered from unusual spring lows and are now near normal.  

Weekly flows for 22 river locations are posted on the above noted web site (under Flood Information) each Friday.

Reservoir Conditions:

The water level of 1406.7 feet on Shellmouth Reservoir in early August is the highest level on record for this time of year. However the reservoir level is declining at more than a foot per week and is expected to reach the normal summer level by August 17 based on normal weather conditions. Outflow of 1600 cubic feet per second will be maintained until the level has declined to 1405 feet at which time a gradual decrease will commence to prevent bank slumping along the Assiniboine River.

Most other reservoirs in Manitoba are either full or just slightly below full supply level. Outflows are being adjusted as required to meet downstream needs. Reservoir water levels may decline significantly during the next few months if dry weather continues; however it is unlikely that water shortages will develop this year.