Water Supply Outlook July 2010

Updated: July 15, 2010

Mountain runoff forecasts (natural volumes for March to September 2010)

Forecasts have increased significantly since May 1 due to very wet weather, with precipitation generally 150 to 180% of normal for May through June in the Milk and Oldman River basins. Forecasts have decreased for the Bow and Red Deer River basins. The North Saskatchewan River basin volume forecasts remain similiar except the forecast volume for North Saskatchewan River at Edmonton, slightly increases from May 1 forecast.

Milk River basin

Oldman River basin

  • Near average except below average to average for the Oldman River at Brocket and above average for the St. Mary Reservoir for the March to September 2010 period
  • Below average to average for July to September
  • March - June recorded volumes highly variable

Bow River basin

  • Much below average for the March to September 2010 period except below average to much below average for Lake Minnewanka and the Highwood River at the Mouth and below average for the Elbow River at Bragg Creek.
  • Below average for July to September, except below average to much below average for the Spray Lake inflow, the Highwood River at the mouth and the Bow River at Banff and Calgary
  • March - June recorded volumes below average to average, except below average to much below average for Lake Minnewanka inflow and the Highwood River at the mouth, and much below average for the Bow River at Banff and Calgary, Spray Lake inflow and the Kananaskis River.

Red Deer River basin

  • Below average to much below average for the Red Deer River at Red Deer and much below average for Dickson Dam inflow March to September 2010 period
  • Below average to much below average for July to September
  • March - June recorded volumes much below average

North Saskatchewan River basin

  • Below average to much below average for the Brazeau and Bighorn Reservoirs and below average the for North Saskatchewan River at Edmonton
  • Below average for July to September
  • March - June recorded volumes much below average for the Brazeau and Bighorn Reservoirs and, the North Saskatchewan River at Edmonton

Precipitation can have a major impact on water supply between now and the end of September. The forecasts above assume that precipitation over the remainder of the winter period and through the summer will be normal. The range of possible precipitation scenarios is large however, and as a result, probable range forecasts and a minimal precipitation forecast of natural runoff volume are also provided for each individual basin. Since more information becomes known over time, forecast ranges will narrow over time. Streamflow volume forecasts are updated monthly from February to May, and again in July. Recorded 2010 volumes are preliminary and subject to change.

Check our Forecaster's Comments throughout the month for updated information regarding runoff conditions.

Mountain snowpack (issued in December to June next year)

Plains Spring Snowmelt Runoff Forecasts (issued in March and April each year)

Plains Snowpack (issued in March and April each year; Cypress Hills mid to late January and February)

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 July 5, 2010 is available here.

Long Lead Precipitation Outlooks

Environment Canada (issued on July 1, 2010): Temperature above normal for Alberta for July-September 2010 except normal in the western parts of Grande Prairie and Clear Hills areas. Precipitation above normal except for normal precipitation in Rocky Mountain and Grande Prairie areas.

National Oceanic and Atmospheric Administration (NOAA) (issued on June 17, 2010): An even chance of below normal, normal, or above normal temperature and precipitation in southern Alberta, for July through September 2010.

Climate indicators : The NOAA reported on July 8, 2010 that La Nino conditions are likely to develop during July-August 2010.

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