Oldman River Basin - Water Supply Forecasts

Average natural runoff volumes are forecast for the March to September 2002 period in the Oldman River basin (Table 3a). Current forecasted values for the March to September period for the Oldman River at Lethbridge would rank 41st lowest in 84-years of record (1912-95). The June 1 forecasts are 7 to 12 % higher than last month's forecast due to a major snowstorm in mid-May. Current runoff volume forecasts for this year are 31 to 51 % higher than recorded runoff volumes last summer.

The first three months of the forecast period has been completed, with March-May 2002 recorded runoff volumes being the below-average at the St. Mary River, Waterton River and the Oldman River at Brocket and Lethbridge and above-average at the Belly River, ranging from 82 to 122 % of average. The remaining volume forecast, which is the March to September 2002 forecast minus the recorded volume to date, is available in Table 3b.