Bow River Basin - Water Supply Forecasts

Generally below-average to much-below-average natural runoff volumes are forecast for the March to September 2003 period in the Bow River basin, except average inflows are expected at Lake Minnewanka (Table 4a). Current forecasts range from 68 to 100% of average for this time of year. The August 1 forecasted volumes decreased (by up to 11%) since last month's forecasts, due to July runoff being very low.

Current March to September 2003 volume forecasts for the Elbow, Highwood, and Kananaskis Rivers are approximately 30 to 40% lower than runoff volumes recorded last year for this period, and 1 to 7% lower at Banff, Lake Minnewanka, Spray Lakes and Calgary. Forecasted volumes are 15 to 34% higher than those recorded in 2001. Current forecasted volumes for the March to September 2003 period for the Bow River at Calgary would rank 23rd lowest in 85-years of record (1912-95).

The first five months of the forecast period are completed, with March-July 2003 recorded runoff volumes ranging from 70 to 102% of average. The remaining volume forecast, which is the March to September 2003 forecast minus the recorded volume to date, is available in Table 4b.