Natural Flow Volumes Summary

Natural runoff volumes recorded during August were generally much-below-average. Volumes in the Bow River at Banff and Calgary and inflows to the Spray Reservoir were the lowest in 91 years of record, while the Cascade Reservoir was fifth lowest. In the southern Bow River basin, naural runoff volumes were 19th lowest in the Elbow River and 34th lowest in the Highwood River. Natural runoff volumes in the Oldman River basin ranged from 5th to 10th lowest, except for the Belly River at Moutainview where it was the lowest on record. In the Red Deer River basin, natural runoff volumes were 8th lowest at the Dickson Dam and 17th lowest at Red Deer. In 84 years of record, natural runoff volumes were second lowest at Edmonton and 12th lowest at Milk River (Table A).

However, natural runoff volume totals for March through August of this year are higher. In the Bow River basin they generally range from 6th to 31st lowest in 91 years of record, below to much below average, except at the Spray Reservoir where it was average. In the Oldman River basin, natural runoff volumes range from below average to average and in the Milk River basin they are below average. Natural runoff volumes in the Red Deer River basin are below to much below average, 16th to 22nd lowest on record. Natural runoff volumes in the North Saskatchewan River basin varied from lowest in 41 years of record at the Brazeau Dam and 8th lowest in 91 years at Edmonton, to average at the Bighorn Dam.

Runoff volume totals for the March through September 2006 period and their percent of average and historical rankings can be found in the following tables:

The final streamflow volume forecast for this year was produced in August, as volumes after September 1 represent a minor portion of the yearly totals. A year in review report will be published next month. Check our Forecaster's Comments throughout the month for updated information regarding runoff conditions.