Water Supply Outlook for Alberta

June 2004

Bow River Basin - Water Supply Forecasts

As of June 1, 2004, March to September 2004 natural runoff volumes are forecast to be below-average in the Elbow and Highwood Rivers, below to much-below-average at Calgary and the Cascade Reservoir, and much-below-average at Banff, Kananaskis and the Spray Reservoir (Table 4a). Current runoff volume forecasts range from 70 to 86% of average. Since May 1, changes in the forecasts range from 3% lower at Banff to 2% higher at Kananaskis. Current March to September 2004 volume forecasts are similar to runoff volumes recorded during the same period last year, except for the Cascade Reservoir, which is forecast to receive 12% less volume than last year. Current forecasted volumes for the March to September 2004 period for the Bow River at Calgary would rank 21st lowest in 91 years of record (1912-2001).

The first three months of the forecast period have been completed, with March-May 2004 recorded runoff volumes ranging from 55 to 121% of average. Bow River basin forecast locations recorded below-average to much-below-average runoff so far. Recorded volume data is preliminary, and is subject to change. Current volumes represent approximately 15 to 25% of the volumes forecasted. The remaining volume forecast, which is the March to September 2004 forecast minus the recorded volume to date, is available in Table 4b. Below-average runoff is forecasted for the June through September 2004 period, except at the Cascade Reservoir where below to much-below-average runoff is forecast. The June through September volume forecast has improved due to near-normal to much-above-normal precipitation in the basin during May, and the delay of May snowmelt. Currently, in early June, snowmelt is well underway and as a result water levels are near average or better in mountain-fed streams.

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