Oldman River Basin - Water Supply Forecasts

As of July 1, 2004, March to September 2004 natural runoff volumes are forecast to be much-below-average at the Oldman Reservoir and in the St.Mary River, below to much below average in the Waterton River and at Lethbridge, and below average in the Belly River (Table 3a). Current forecasted values for the March to September 2004 period for the Oldman River at Lethbridge would rank 18th lowest in 91-years of record (1912-2001). Current runoff volume forecasts range from 66 to 86% of average, 1 to 8% lower than last month's forecasted volumes. The March to September 2004 forecast volumes are 4 to 13% higher than those recorded during the same period last year, except at Brocket, which is 4% lower.

The first four months of the forecast period have been completed, with March-June 2004 recorded runoff volumes ranging from 58 to 86% of average. Runoff in the Belly River was below average, below to much below average in the Waterton River, and at all other forecast locations much-below-average. Current volumes represent approximately two-thirds 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. Below-average runoff is forecasted for the July through September 2004 period, except in the St.Mary River and at Brocket where below to much-below-average runoff is forecast.