Water Supply Outlook for Alberta

May 2013

Water Supply Forecast as of May 1, 2013 - Oldman River Basin (Natural Flows)

Volume Forecast for May 1 to September 30, 2013 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 2013 Volume as a % of Average Ranking (lowest to highest)
St. Mary River 620,000** 104 88-118 74 44/99 90*** 42/99
Belly River 216,000* 104 95-116 86 48/99 66*** 27/99
Waterton River 543,000* 111 98-128 87 51/99 83*** 39/99
Oldman River near Brocket 871,000* 100 93-106 87 44/99 93*** 44/99
Oldman River at Lethbridge 2,526,000* 101 88-114 76 52/99 90*** 43/99

*NOTE: The forecast shown is the March to September 2013 forecast minus the recorded volume to date

** - This value is the natural volume and includes the U.S. share
*** - Recorded 2013 natural volumes are preliminary and subject to change
Average is calculated for the March 1 to September 30 period 1981 to 2009

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