Water Supply Outlook for Alberta

May 2009

Water Supply Forecast as of May 1, 2009 - Oldman River Basin (Natural Flows)

Volume Forecast for May 1 to September 30, 2009 Year to date
Locations Volume in dam3 Volume as a % of Average Probable Range as a % of Average Potential Minimum as % of Average Forecast Ranking (lowest to highest) Recorded March-April 2009 Volume as a % of Average Ranking (lowest to highest)
St. Mary River 590,000** 88 70-107 58 31/91 61*** 20/91
Belly River 201,000* 90 75-104 70 30/91 94*** 45/91
Waterton River 522,000* 95 74-109 64 41/91 53*** 10/91
Oldman River near Brocket 890,000* 92 75-115 60 44/91 52*** 9/91
Oldman River at Lethbridge 2,308,000* 88 67-109 55 38/91 53*** 13/91

*NOTE: The forecast shown is the March to September 2009 forecast minus the recorded volume to date

** - This value is the natural volume and includes the U.S. share
*** - Recorded 2009 natural volumes are preliminary and subject to change Average is calculated for the period 1912 to 2001

NOTE: There is: a 50% chance that the actual natural flow will fall within the probable range given; a 25% chance that the actual flow will be less than the lower bound of the probable range given; and a 10% chance that the actual natural flow will be less than the reasonable minimum. Actual day to day streamflow conditions may vary throughout the season as a result of the effects of streamflow diversion and reservoir storage.

For technical enquires about this web page please contact Alberta Environment - Environmental Management Water Management Operations Branch at AENV-WebWS@gov.ab.ca