Bow River Basin - Water Supply Forecasts

Below-average to much-below-average natural runoff volumes are forecast for the March to September 2003 period in the Bow River basin (Table 4a). Current forecasts range from 65 to 84% of average for this time of year. The April 1 forecasts are higher (by 2 to 12%) than last month's forecasts due to above-normal precipitation in the basin headwaters during March. Forecast volumes for the Highwood, Elbow, and Kananaskis Rivers improved the most and are slightly higher than the rest of the Bow River basin, because of near average soil moisture conditions. Current March to September 2003 volume forecasts are lower than runoff volumes recorded last year for this period, but are higher than those recorded in 2001. Current forecasted volumes for the March to September 2003 period for the Bow River at Calgary would rank 16th lowest in 85-years of record (1912-95).

The first month of the forecast period has been completed, with March 2003 recorded runoff volumes ranging from 68 to 151 % of average. The southernmost basins, the Elbow and Highwood, had above-average to much-above-average runoff in March, due to the quick melting of their plains and foothills snowpack. The remaining volume forecast, which is the March to September 2003 forecast minus the recorded volume to date, is available in Table 4b.