Bow River Basin - Water Supply Forecasts

As of August 1, 2006, natural runoff volumes for the March to September 2006 period are forecast to be generally below average in the Bow River basin, except much below average at Banff, below to much below average into the Cascade Reservoir, and average into the Spray Lakes Reservoir (Table 5a). Current natural runoff volume forecasts range from 71 to 103% of average in the basin. Current forecasts have dropped by 9 to 12% of average since the July 1 forecasts, except by 5% of average for the Highwood and Elbow Rivers. The current forecasted volume for the Bow River at Calgary would rank 25th lowest in 91-years of record (1912-2001).

The first five months of the forecast period have been completed, with March-July 2006 recorded natural runoff volumes ranging from 71 to 106 % of average in the basin. Volumes thus far have generally been below average, except much below average at Banff, below to much below average into the Cascade Reservoir, and average to above average into the Spray Lakes Reservoir. Recorded volume data is preliminary, and is subject to change. The remaining volume forecast, which is the March to September 2006 forecast minus the recorded volume to date, is available in Table 5b. Below average natural runoff volumes are forecast for the August - September 2006 period, except at the Spray Lakes Reservoir and in the Elbow River where below average to average inflows are expected.