Lake Ontario Outflow Changes

The regulation plan (Plan 2014) specifies a weekly average Lake Ontario outflow from Saturday through the following Friday. Throughout the year, the Lake Ontario outflow, which is managed at the Moses-Saunders Dam, may be modified more frequently depending on the conditions in Lake Ontario and the St. Lawrence River. There are two different types of outflow modifications: 

  1. Operational Adjustments, which do not have to be offset at a later date, and
  2. Deviations, which are classified as "minor" or "major" and generally do have to be offset at a later date.

Further details are available in the Directive on Operational Adjustments, Deviations and Extreme Conditions (https://ijc.org/en/loslrb/who/directives/deviations)

Summary of Outflow Changes in 2022

Summary of Outflow Changes for 2023

As of January 7, 2023, the water level of Lake Ontario was equivalent to the level it would have been if no outflow deviations from Plan 2014 had been conducted in 2022. 

January 27, 2023:

The Lake Ontario outflow has been reduced to promote the formation of an ice cover in the Beauharnois Canal. This outflow reduction is considered an operational adjustment in accordance with the Plan 2014 I Limit. About 2 km of slush ice has accumulated in the Beauharnois Canal and there has been a significant rise in the tension on the ice booms.

February 2, 2023:

Ice began to form in the Beauharnois Canal on January 27. Since then, the outflow has been operationally adjusted several times (decreased on January 27, increased on January 29 and 30, decreased on January 31, and increased on February 1) in accordance with the Plan 2014 I Limit and in response to changing ice conditions.

The outflow target for the week of February 4 through 10 is the applicable Rule Curve flow of 7,720 m3/s. However, the outflow will continue to be operationally adjusted in accordance with the Plan 2014 I Limit, as needed, to promote the formation and stability of an ice cover in the Beauharnois Canal.


Winter Outflow Changes

During the winter months, the outflow will be operationally adjusted in accordance with the Plan 2014 I Limit, as needed, to promote the formation and stability of ice covers in the Beauharnois Canal and on Lake St. Lawrence. For more information,

 

DATE HOUR OUTFLOW OUTFLOW NOTES
(YYYY-MM-DD) (HHMM) (m3/s) (cfs)  
2023-02-02 1701 6,800 240,100 I Limit
2023-02-01 1901 7,700 271,900 Rule Curve
2023-01-31 2001 7,000 247,200 I Limit
2023-01-30 1301 7,700 271,900 Rule Curve
2023-01-29 1201 7,500 264,900 I Limit
2023-01-27 1401 7,000 247,200 I Limit
2023-01-21 0001 7,620 269,100 Rule Curve
2023-01-14 0001 7,600 268,400 Rule Curve
2023-01-07 0001 7,490 264,500 Rule Curve

To view outflow change records from previous years, please use the links below:

Flow Changes - 2022

Flow Changes - 2021

Flow Changes - 2020

Flow Changes - 2019

Flow Changes - 2018

Flow Changes - 2017

Flow Changes - 2016

Flow Changes - 2015

Flow Changes - 2014

Flow Changes - 2013

Flow Changes - 2012

Flow Changes - 2011