Mountain Water Supply Forecast Summary

As of August 1, 2008, above to much above average natural runoff volumes are forecast for this year (March - September 2008) for most rivers from the North Saskatchewan River south to the Oldman River basin. Average volumes are expected for the Oldman River at Brocket and Lethbridge and the Belly River near Mountainview. Below average volumes are forecast for the Milk River at Milk River and at the Eastern Crossing, and below to much below average volumes are forecast for the Bow River at Banff (Table 1).

Natural runoff volumes recorded for March-July were among the thirty highest in up to 91 years of record for the Red Deer, Elbow, Highwood and Waterton Rivers, the Bow River at Calgary, the North Saskatchewan River at Edmonton, and into the Cascade and Brazeau Reservoirs. In other mountain basins, volumes recorded so far have generally ranged from average to above average, except below average for the Milk River at Milk River and at the Eastern Crossing, and below to much below average for the Bow River at Banff. Recorded volume data is preliminary and is subject to change.

Average natural runoff volumes are forecast for the remainder of the year (August - September 2008), except above average for the Red Deer and Elbow Rivers, the North Saskatchewan River at Edmonton, and into the Spray, Brazeau and Cascade Reservoirs, and below average to average for the Oldman, Belly and Milk Rivers and below average for the Bow River at Banff. Forecasts assume that precipitation over the remaining summer period will be normal. Precipitation will have a major impact on the summer water supply forecast between now and the end of September. This is the last month of streamflow forecasts for the year. Next month an update on measured volumes, precipitation and reservoir levels will be provided. Check our Forecaster's Comments throughout the month for updated information regarding runoff conditions.