Water Supply Outlook for Alberta

May 2012

Water Supply Forecast as of May 1, 2012 - Oldman River Basin (Natural Flows)

Volume Forecast for May 1 to September 30, 2012 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 2012 Volume as a % of Average Ranking (lowest to highest)
St. Mary River 610,000** 91 81-101 76 36/91 118*** 66/91
Belly River 188,000* 84 74-96 69 27/91 186*** 88/91
Waterton River 584,000* 107 93-114 86 57/91 114*** 66/91
Oldman River near Brocket 1,057,000* 109 83-128 69 59/91 135*** 72/91
Oldman River at Lethbridge 2,655,000* 101 78-117 69 55/91 103*** 54/91

*NOTE: The forecast shown is the March to September 2012 forecast minus the recorded volume to date

** - This value is the natural volume and includes the U.S. share
*** - Recorded 2012 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