Lake Ontario Outflow Changes
Outflows from Lake Ontario are established by the International Lake Ontario - St. Lawrence River Board in accordance with the current regulation plan and the International Joint Commission's Orders of Approval. The table below displays the outflow changes that have occurred this year. All flows are reported in cubic metres and cubic feet per second.
The water level of Lake Ontario remains below the applicable low Criterion H14 threshold. The Board reached consensus to implement a deviation strategy as authorized by the IJC’s Directive. For the coming week, the average Lake Ontario outflow is expected to be 7,560 m³/s (267,000 cfs), which is 200 m³/s (7,060 cfs) less than the amount prescribed by the Rule Curve of the regulation plan. The Board will continue to monitor conditions and the effects of the deviation strategy closely while simultaneously tracking weather forecasts and drought conditions.
| DATE | HOUR/HEURE | OUTFLOW/DÉBIT | OUTFLOW/DÉBIT |
| (YYYY-MM-DD) | (HHMM) | (m3/s) | (cfs) |
| 2021-06-19 | 0001 | 7,560 | 267,000 |
| 2021-06-12 | 0001 | 7,600 | 268,400 |
| 2021-06-05 | 0001 | 7,620 | 269,100 |
| 2021-05-29 | 0001 | 7,840 | 276,900 |
| 2021-05-22 | 0001 | 7,970 | 281,500 |
| 2021-05-15 | 0001 | 8,090 | 285,700 |
| 2021-05-08 | 0001 | 8,070 | 285,000 |
| 2021-05-01 | 0001 | 7,920 | 279,700 |
| 2021-04-24 | 0001 | 7,410 | 261,700 |
| 2021-04-16 | 2101 | 7,350 | 259,600 |
| 2021-04-15 | 2101 | 7,820 | 276,200 |
| 2021-04-10 | 0001 | 7,420 | 262,000 |
| 2021-04-03 | 0001 | 7,980 | 281,800 |
| 2021-03-20 | 0001 | 7,380 | 260,600 |
| 2021-03-13 | 0001 | 8,000 | 282,500 |
| 2021-03-06 | 0001 | 8,080 | 285,300 |
| 2021-03-01 | 0001 | 8,140 | 287,500 |
| 2021-02-21 | 1501 | 8,600 | 303,700 |
| 2021-02-20 | 1201 | 8,400 | 296,600 |
| 2021-02-19 | 1201 | 8,000 | 282,500 |
| 2021-02-18 | 1801 | 7,600 | 268,400 |
| 2021-02-18 | 0701 | 7,400 | 261,300 |
| 2021-02-17 | 1101 | 7,000 | 247,200 |
| 2021-02-16 | 1401 | 6,600 | 233,100 |
| 2021-02-12 | 1401 | 7,000 | 247,200 |
| 2021-02-11 | 1601 | 7,400 | 261,300 |
| 2021-02-10 | 1901 | 8,300 | 293,100 |
| 2021-02-09 | 2001 | 8,500 | 300,200 |
| 2021-02-05 | 1801 | 8,800 | 310,800 |
| 2021-02-04 | 1201 | 8,200 | 289,600 |
| 2021-02-03 | 1401 | 7,700 | 271,900 |
| 2021-02-01 | 1501 | 7,100 | 250,700 |
| 2021-01-31 | 1801 | 6,900 | 243,700 |
| 2021-01-28 | 1601 | 7,200 | 254,300 |
| 2021-01-26 | 1001 | 7,700 | 271,900 |
| 2021-01-24 | 1701 | 7,200 | 254,300 |
| 2021-01-23 | 1701 | 8,400 | 296,600 |
| 2021-01-19 | 1501 | 9,200 | 324,900 |
| 2021-01-16 | 1701 | 9,400 | 332,000 |
| 2021-01-14 | 1201 | 9,200 | 324,900 |
| 2021-01-12 | 1201 | 9,500 | 335,500 |
| 2021-01-09 | 1501 | 9,400 | 332,000 |
| 2021-01-07 | 1301 | 9,300 | 328,400 |
| 2021-01-05 | 1001 | 9,200 | 324,900 |
| 2021-01-04 | 1701 | 9,400 | 332,000 |
| 2021-01-03 | 1301 | 9,500 | 335,500 |
| 2021-01-01 | 0801 | 9,400 | 332,000 |
| 2020-12-26 | 0001 | 8,090 | 285,700 |
To view outflow change records from previous years, please use the links below: