Mountain Water Supply Forecast Summary

Below-average to much-below-average runoff volumes are forecast for the March through September 2003 period in the Oldman, Milk and Bow River basins. Below-average to average runoff volumes are forecast for this year in the North Saskatchewan River basin and average to above-average volumes are expected in the Red Deer River basin (Table 1). Forecasted volumes are higher than those recorded in 2001. Forecasted volumes are generally much higher than those recorded last year in the Red Deer and North Saskatchewan River basins, except for the Bighorn Reservoir, where forecasted volumes are 4% lower. Forecasted volumes are lower than last year's recorded volumes in the northern half of the Bow River basin, and much lower in the southern half of the Bow River basin as well as in the Milk and Oldman River basins.

Runoff volumes thus far, during March through July 2003, range from 65 to 85% of average in the Oldman and Milk River basins, 70 to 100% of average in the Bow River basin, and 90 to 115% of average in the North Saskatchewan and Red Deer River basins.

Below-average to much-below-average runoff volumes are forecast for August through September 2003 in the Oldman, Milk, Bow, Red Deer and North Saskatchewan River basins.

These forecasts assume that precipitation over the remainder of the summer period will be normal. Mountain snowmelt is essentially complete for this year. This is the last streamflow volume forecast for this year, as volumes after September 1 represent a minor portion of the yearly totals. Monthly updates of recorded volumes, precipitation, and reservoir storages will continue. A year in review report will be published in October. Check our Forecaster's Comments throughout the month for updated information regarding runoff conditions.