Water Supply Outlook for Alberta

June 2003

Table 3b - Water Supply Forecast as of June 1, 2003 - Oldman River Basin (Natural Flows)

Volume Forecast for June 1 to September 30 Year to date
Locations Volume in dam3 Volume as a % of Average Probable Range as a % of Average Reasonable Minimum as % of Average Forecast Ranking (lowest to highest) Recorded March-May 2003 Volume as a % of Average Ranking (lowest to highest)
St. Mary River 327,000** 66 49-94 46 13/85 91*** 30/85
Belly River 120,000* 74 55-111 51 16/85 94*** 45/85
Waterton River 312,000* 75 62-117 55 26/85 75*** 17/85
Oldman River near Brocket 483,000* 75 56-108 44 29/85 88*** 32/85
Oldman River at Lethbridge 1,228,000* 67 46-101 38 20/85 89*** 32/85

*NOTE: The forecast shown is the March to September 2003 forecast minus the recorded volume to date

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** - This value is the natural volume and includes the U.S. share
*** - Recorded 2003 natural volumes are preliminary and subject to change
Average is calculated for the period 1912 to 1995

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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