Water Supply Outlook for Alberta

May 2007

Table 4b - Water Supply Forecast as of May 1, 2007 - Oldman River Basin (Natural Flows)

Volume Forecast for May 1 to September 30, 2007 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 2007 Volume as a % of Average Ranking (lowest to highest)
St. Mary River 563,000** 84 68-96 62 26/91 158*** 80/91
Belly River 209,000* 94 83-113 75 34/91 95*** 46/91
Waterton River 504,000* 92 76-109 68 35/91 130*** 74/91
Oldman River near Brocket 858,000* 89 71-110 59 38/91 149*** 78/91
Oldman River at Lethbridge 2,260,000* 86 65-95 55 36/91 133*** 73/91

*NOTE: The forecast shown is the March to September 2007 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 2007 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