Water Supply Outlook for Alberta

May 2005

North Saskatchewan River Basin - Water Supply Forecasts

As of May 1, 2005, natural runoff volumes for the March to September 2005 period are forecast to be average into the Bighorn and Brazeau Reservoirs, and below average to average in the North Saskatchewan River at Edmonton (Table 6). Current forecasts in the basin range from 92 to 98% of average, 1 to 4% lower than last month's forecasts due to precipitation during April in the upper basins being generally a quarter to a third of normal. Current forecasted values for the March to September period for the North Saskatchewan River at Edmonton would rank 39th lowest in 91-years of record (1912-2001). The May 1, 2005 forecasts are 4 and 15% higher than volumes recorded over the same March-September time period last year at the Brazeau Reservoir and Edmonton, respectively, and 5% lower than last year at the Bighorn Reservoir.

The first two months of the forecast period have been completed, with March-April 2005 recorded natural runoff volumes at Lake Abraham being the highest in 30 years of record at 164% of average due to early melting of what was an average snowpack at the beginning of April. Runoff into the Brazeau Reservoir has also been much above average, at 139% of average, while Edmonton recorded natural runoff which was average, at 96% of average. Recorded volume data is preliminary and is subject to change. With a lot of snow having melted in April, forecasts for May through September are for below average to average natural runoff volumes at the Brazeau Reservoir and Edmonton, and below average volume at the Bighorn Reservoir. This remaining volume forecast, which is the March to September 2005 forecast minus the recorded volume to date, is available in Table 6b.

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