Oldman River Basin - Water Supply Forecasts

As of February 1, 2006, natural runoff volumes for the March to September 2006 period are forecast to be below average for the Belly River, below average to average for the Oldman River at Lethbridge and for the Waterton and St. Mary Rivers, and average into the Oldman Dam near Brocket (Table 4). Current forecasted values for the March to September 2006 period for the Oldman River at Lethbridge would rank 40th lowest in 91-years of record (1912-2001). Current natural runoff volume forecasts range from 89 to 98% of average. The March to September 2006 forecast volumes are 4 to 17% higher than those recorded during the same period last year for the Waterton, Belly and St. Mary Rivers, and 17 to 34% lower than last year at Lethbridge and Brocket, where flooding was more prevalent.

Despite above average snowpack in the mountains and wet soil conditions due to heavy summer and fall precipitation last year, below to much below average snowpack at lower elevations has decreased the runoff forecasts somewhat.