North Saskatchewan River Basin - Water Supply Forecasts

Natural runoff volumes for the March to September 2003 period are forecast to be below-average for the North Saskatchewan River basin, ranging from 89 to 94% of average (Table 6a). The forecasted volumes for Edmonton and the Brazeau Reservoir represent significant improvements of 19 and 21%, respectively, since April 1, due to much-above-normal April precipitation in the lower elevations. The Bighorn Reservoir, which is in the mountains, had its forecast improve by only 4% since the April storm had less impact on the upper elevations of the North Saskatchewan River basin. The May 1 forecasts for Edmonton and the Brazeau Reservoir are 18% higher than volumes recorded over the same time period last year, while the Bighorn Reservoir forecast is 9% lower than last year's volume. Current forecasted volumes are higher than those recorded in 2001 by 11 to 23%. Current forecasted values for the March to September period for the North Saskatchewan River at Edmonton would rank 35th lowest in 84-years of record (1912-95).

The first two months of the forecast period have been completed, with March-April 2003 recorded runoff volumes ranging from 139 to 154% of average. Volumes recorded at the Bighorn and Brazeau reservoirs were the highest and third-highest in 18 and 29 years of record, respectively. The remaining volume forecast, which is the March to September 2003 forecast minus the recorded volume to date, is available in Table 6b.