Lake Ontario Outflow Changes

The regulation plan (Plan 2014) specifies a weekly average Lake Ontario outflow from Saturday through the following Friday, inclusive. At times, the outflow is adjusted more frequently depending on conditions in the St. Lawrence River. For example, outflows were adjusted frequently in January and early February to promote and maintain stable ice conditions.

April 12-23, 2022 Update:

The outflow was reduced to allow Hydro-Québec to install safety booms near their facilities in the lower portion of the St. Lawrence River. Installation of these safety booms occurs every spring to improve safety for recreational users (e.g. swimmers and kayakers). Installation of the safety booms was successfully completed on April 23. This temporary period of reduced flows is considered a minor deviation from the regulation plan and will be offset as soon as conditions permit. For more information on the Board’s minor deviation authority, please read the Directive located here: https://ijc.org/en/loslrb/who/directives/deviations.

May 12, 2022 Update:

The outflow is expected to be maintained at 8,800 m3/s through May 22 to allow New York Power Authority to install a permanent safety barrier at Long Sault Dam. The plan-prescribed flow (L Limit) for May 14 through 20 is 8,930 m3/s. This temporary period of reduced flows is considered a minor deviation from the regulation plan and will be offset as soon as conditions permit. For more information on the Board’s minor deviation authority, please read the Directive located here: https://ijc.org/en/loslrb/who/directives/deviations.

DATE HOUR OUTFLOW OUTFLOW
(YYYY-MM-DD) (HHMM) (m3/s) (cfs)
2022-05-10 0501 8,800 310,800
2022-05-09 1201 9,040 319,200
2022-05-08 1201 8,950 316,100
2022-05-07 1101 8,800 310,800
2022-05-06 1201 8,650 305,500
2022-04-28 1201 8,550 301,900
2022-04-27 1201 8,450 298,400
2022-04-24 1101 8,300 293,100
2022-04-22 1701 8,100 286,000
2022-04-21 1601 7,900 279,000
2022-04-20 1101 7,600 268,400
2022-04-11 1201 8,100 286,000
2022-04-10 1201 7,900 279,000
2022-04-09 1201 7,550 266,600
2022-04-08 1501 7,700 271,900
2022-04-08 0901 7,900 279,000
2022-04-02 0001 8,730 308,300
2022-03-29 1101 8,690 306,900
2022-03-28 1101 8,600 303,700
2022-03-27 1101 8,300 293,100
2022-03-26 1801 8,100 286,000
2022-03-24 1401 8,000 282,500
2022-03-23 1101 8,620 304,400
2022-03-22 1101 8,300 293,100
2022-03-20 1401 8,000 282,500
2022-03-19 0001 8,700 307,200
2022-03-12 0001 8,660 305,800
2022-03-09 1201 8,600 303,700
2022-02-26 0001 8,520 300,900
2022-02-19 0001 8,180 288,900
2022-02-11 1201 8,210 289,900
2022-02-09 1201 8,100 286,000
2022-02-07 1201 7,900 279,000
2022-02-04 1201 7,700 271,900
2022-02-02 1201 7,500 264,900
2022-01-31 1201 7,300 257,800
2022-01-28 1201 7,100 250,700
2022-01-26 1201 6,900 243,700
2022-01-25 1101 6,700 236,600
2022-01-24 1101 6,500 229,500
2022-01-23 1501 6,200 219,000
2022-01-22 1601 6,450 227,800
2022-01-20 1601 6,200 219,000
2022-01-20 1501 6,600 233,100
2022-01-19 1501 7,000 247,200
2022-01-17 0401 6,600 233,100
2022-01-14 1801 7,200 254,300
2022-01-12 1801 7,950 280,800
2022-01-12 1301 7,600 268,400
2022-01-11 1701 7,400 261,300
2022-01-10 1501 8,100 286,000
2022-01-08 0001 8,310 293,500
2022-01-04 1201 8,410 297,000
2022-01-01 0001 8,530 301,200

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

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