Water Supply Outlook November 2011
Updated: November 7, 2011
Recorded natural runoff volumes from March to September 2011
Natural runoff volumes from March to September 2011 were generally much above average in the Milk River, Oldman River, Highwood River and Red Deer River Basins, average to above average in the Bow River and North Saskatchewan River Basins. The heavy precipitation in southern Alberta this summer produced much above normal runoff particularly in the Milk River, Oldman River, Highwood River and Red Deer River.
Natural runoff volumes recorded from March to September 2011 for most of the rivers in the Milk River, Oldman River, Bow River, Red Deer River and North Saskatchewan River Basins ranked from 67 to 88th highest in 91 years of record. However, the Bow River at Banff and Kananaskis River reached only the 44th and 46th highest in 91 years of record. Lake Abraham Inflow and Brazeau Reservoir Inflow ranked from 13 to 32 highest in 30 and 41 years of record respectively.
The average difference between forecast and recorded natural volumes were 7 to 15% for the North Saskatchewan River and Bow River Basins. However, due to much above normal precipitation in southern Alberta this summer, runoff volumes forecasts were underestimated in the Oldman River (30%) and Red Deer River (29%) Basins.
Milk River basin- March - September recorded volumes much above average for the Milk River due to heavy precipitation in southern Alberta this summer.
- Runoff in this basin is naturally highly variable. With very high precipitation totals this year, volumes were closer to the high end of the forecast range (upper quartile forecasts).
- No water supply forecasts were issued this year due to much above normal precipitation in the Milk River Basin.
- March - September recorded volumes much above average for the St. Mary River, Belly River, Waterton River and Oldman River.
- Three months forecasts (March, May and August) issued this past year for 5 locations were on average, accurate within 30%. Runoff was closer to the upper quartile forecasts due to high precipitation totals.
- March - September recorded volumes average to above average for the Bow River and Kananaskis River, above average to much above average for the Elbow River, Highwood River and Lake Minnewanka Inflow.
- Three months forecasts (March, May and August) issued this past year for 6 locations were on average, accurate within 15%. Runoff was closer to the average and upper quartile forecasts.
- March - September recorded volumes above average to much above average for the Red Deer River at Dickson Dam and City of Red Deer.
- Three months forecasts (March, May and August) issued this past year for 2 locations were on average, accurate within 29%. Runoff was closer to the upper quartile forecasts due to high precipitation totals.
- March - September recorded volumes average to slightly above average for Lake Abraham inflow, Brazeau Reservoir inflow and North Saskatchewan River at Edmonton.
- Three months forecasts (March, May and August) issued this past year for 3 locations were on average, accurate within 7%. Runoff was close to average.
Note: The recorded 2011 natural flow volumes are preliminary and subject to change.
Check our Forecaster's Comments for updated information regarding runoff conditions.
Precipitation
Contoured maps of precipitation amounts and as a percent of normal for the past month and for current and recent seasons are available here. Maps of precipitation amounts for the most recent day, week and month to date are available here.
Soil Moisture
Alberta Agriculture models soil moisture for non-mountainous, agricultural areas of Alberta. Modelled soil moisture compared to average as of October 31, 2011 is available here.
Long Lead Precipitation Outlooks
Environment Canada (issued on November 1, 2011): temperature and precipitation for the November 2011 through January 2012 period:
- normal precipitation in southern and east central Alberta. Below normal precipitation in northern and west central Alberta.
- below normal temperatures throughout the entire province.
National Oceanic and Atmospheric Administration (NOAA) (issued on October 20, 2011): normal precipitation and below normal temperature for southern Alberta for November 2011 through January 2012.
Climate indicators: The NOAA reported on November 7, 2011 that La Nina is expected to strengthen and continue through the Northern Hemisphere during the winter of 2011 - 2012.
Note that forecasting weather for such a long time period into the future is very difficult, and so the historical accuracy has been variable, dependent on location and time period, and is often low, more so for precipitation than temperature. Environment Canada provides an assessment of their forecast method's historical accuracy on their website.
Reservoir storage
Water storage volumes in the major irrigation and hydroelectric reservoirs of the Milk, Oldman, Bow, Red Deer North Saskatchewan, and Athabasca River basins is updated each weekday and is available in the Provincial Reservoir Storage Summary.
Questions
Background information on the Water Supply Outlook is available in Frequently Asked Questions
Media Contact:
Communications Division, Alberta Environment
Phone: (780) 427-6267
