Water Supply Outlook for Alberta

August 2009

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

Volume Forecast for August 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-July 2009 Volume as a % of Average Ranking (lowest to highest)
St. Mary River 68,500** 70 61-89 50 21/91 69*** 15/91
Belly River 27,700* 77 64-97 58 24/91 79*** 18/91
Waterton River 43,800* 71 53-103 45 28/91 75*** 20/91
Oldman River near Brocket 68,400* 63 54-81 40 21/91 58*** 14/91
Oldman River at Lethbridge 217,000* 65 52-88 36 23/91 62*** 14/91

*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.

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