Water Supply Outlook for Alberta

April 2004

Oldman River Basin - Water Supply Forecasts

As of April 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 St. Mary and Belly Rivers where much-below-average volumes are expected (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 70 to 76% of average, 0 to 2% less than last month's forecasted volumes. The March to September 2004 forecast volumes are 4 to 12% higher than those recorded during the same period last year, in all but the Belly River basin, where volumes are forecast to be 7% lower than last year's.

The first month of the forecast period has been completed, with March 2004 recorded runoff volumes ranging from 48 to 110% of average. Runoff in the Belly and at the Oldman Reservoir was average to above-average and below-average at Lethbridge and in the Waterton and St.Mary Rivers. Recorded volume data is preliminary, due to ice effects, and is subject to change. March volumes typically comprise a small portion of the March to September total. The remaining volume forecast, which is the March to September 2004 forecast minus the recorded volume to date, is available in Table 3b.

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