Oldman River Basin - Water Supply Forecasts

As of June 1, 2004, below-average to much-below-average natural runoff volumes are forecast for the March to September 2004 period in the Oldman River basin, except for the Belly River where below-average volume is expected (Table 3a). Current forecasted values for the March to September 2004 period for the Oldman River at Lethbridge would rank 20th lowest in 91-years of record (1912-2001). Current runoff volume forecasts range from 70 to 87% of average, 0 to 13% higher than last month's forecasted volumes. The March to September 2004 forecast volumes are 4 to 15% higher than those recorded during the same period last year.

The first three months of the forecast period have been completed, with March-May 2004 recorded runoff volumes ranging from 64 to 97% of average. Runoff in the Belly River was average, and at all other forecast locations below-average to much-below-average. Current volumes represent approximately one-third of the volumes forecasted. Recorded volume data is preliminary, and is subject to change. The remaining volume forecast, which is the March to September 2004 forecast minus the recorded volume to date, is available in Table 3b. The June through September volume forecast has improved significantly due to above-normal precipitation in the basin during May. Below-average runoff is forecasted for the June through September 2004 period, except in the Belly River where below to much-below-average runoff is forecast, and at the Oldman Reservoir, where below-average to average runoff is expected.