Picture of Lake of the Woods, Kenora, Ontario

Standard Rule Curve to Be Followed this Spring 2021 on Rainy Lake


In accordance with the 2018 Supplementary Order, the Water Levels Committee of the International Rainy-Lake of the Woods Watershed Board has determined that the standard rule curve will be used this spring to direct the operation of the dam at the outlet of Rainy Lake. Current and forecast conditions, as outlined below, do not support the use of the high flood risk rule curve at this time.

On Wednesday, March 3rd the Water Levels Committee hosted a Pre-Spring Engagement Webinar. During this webinar, the Engineering Advisors provided a summary of basin conditions and seasonal forecast information to the Water Levels Committee and the invited representatives of basin interests. Webinar participants were encouraged to provide their own local knowledge and expertise and share any concerns or additional information for consideration in advance of the freshet season. The Water Levels Committee made its decision based on the following information:

Current Conditions

  • Base flow conditions are lower than normal for this time of year.
  • To date, overall average winter temperatures are warmer than 2020, and much warmer than 2014 when significant high-water levels were experienced in the basin.
  • The accumulated snowpack is lower than normal and fall in the 20 to 40 percentile range based on historic records.
  •  Overall, the past winter has been mild when measured by the accumulated snow and severity of cold weather.

Forecasted Conditions

  • Current projections of the El Niño–Southern Oscillation (ENSO) in the Pacific Ocean show a 60% chance of a neutral condition.
    • Historic data since 1970 show that high water years occur most often when La Niña conditions are present and are less likely during neutral conditions.
  • The current NOAA long-term forecasts of temperature show equal probabilities of low, normal or high temperature through March, April, and May.
  • The current NOAA long-term forecast of precipitation shows a 30% chance above normal precipitation through March, April, and May.

Feedback from basin interests

Feedback from basin interests is consistent with the information provided by the Water Levels Committee at the pre-spring engagement.

  • Ice thickness on the lakes this winter is much less than in a normal winter.
  • The snowpack is disappearing.
  • A conservative approach to releases out of Namakan and Rainy Lakes would be prudent given the current conditions.

The Water Levels Committee will continue to monitor basin conditions and forecasts as the spring progresses. If conditions change as the year progresses and the risk of flooding changes, the Water Levels Committee may direct the Companies to target specific bands within the standard rule curve for Rainy Lake. For updated information on Water Levels Committee decisions, please visit the Water Level Decisions & Data page of the International Rainy - Lake of the Woods Watershed Board website.


Scott Jutila:                       (651) 290-5631                              scott.a.jutila@usace.army.mil

Andrew Liddiard:            (800) 661-5922 ext. 4                    aliddiard@lwcb.ca