Water Supply Outlook for Alberta

May 2010

Water Supply Forecast as of May 1, 2010 - Oldman River Basin (Natural Flows)

Volume Forecast for May 1 to September 30, 2010 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 2010 Volume as a % of Average Ranking (lowest to highest)
St. Mary River 558,000** 83 66-100 55 24/91 71*** 29/91
Belly River 193,000* 87 73-98 66 27/91 97*** 47/91
Waterton River 473,000* 86 69-101 57 29/91 80*** 35/91
Oldman River near Brocket 801,000* 83 55-102 50 33/91 75*** 34/91
Oldman River at Lethbridge 2,167,000* 83 56-101 47 31/91 73*** 29/91

*NOTE: The forecast shown is the March to September 2010 forecast minus the recorded volume to date

** - This value is the natural volume and includes the U.S. share
*** - Recorded 2010 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