Oldman River Basin - Water Supply Forecasts

Below-average to much-below-average natural runoff volumes are forecast for the March to September 2003 period in the Oldman River basin, ranging from 66 to 84% of average (Table 3a). Current forecasts are 3 to 5% lower than last month's forecasts due to very low runoff and precipitation during July. The March to September 2003 forecast volumes range from 6% higher than 2001 in the Waterton River to 28% higher than 2001 in the Oldman River near Brocket, and are approximately half the volumes recorded last year. Current forecasted values for the March to September 2003 period for the Oldman River at Lethbridge would rank 18th lowest in 85 years of record (1912-95).

The first five months of the forecast period have been completed, with March-July 2003 recorded runoff volumes ranged from 67 to 85% of average. The remaining volume forecast, which is the March to September 2003 forecast minus the recorded volume to date, is available in Table 3b.