Water Supply Outlook for Alberta

May 2006

Table 4b - Water Supply Forecast as of May 1, 2006 - Oldman River Basin (Natural Flows)

Volume Forecast for May 1 to September 30, 2006 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-April 2006 Volume as a % of Average Ranking (lowest to highest)
St. Mary River 596,000** 89 75-112 66 31/91 102*** 52/91
Belly River 211,000* 95 83-110 75 35/91 109*** 60/91
Waterton River 529,000* 97 79-112 74 43/91 103*** 52/91
Oldman River near Brocket 914,000* 95 77-118 66 48/91 124*** 65/91
Oldman River at Lethbridge 2,311,000* 88 67-100 63 38/91 126*** 74/91

*NOTE: The forecast shown is the March to September 2006 forecast minus the recorded volume to date

Click on the site Location to see the Water Supply Forecast graphically

** - This value is the natural volume and includes the U.S. share
*** - Recorded 2006 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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