Outflow Strategy
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Copyrights : International St. Lawrence River Board of Control

Lake Ontario Outflow Strategy
(January 16, 2004)

The International St. Lawrence River Board of Control (Board) has reviewed conditions in the Lake Ontario - St. Lawrence River basin and decided to revise its outflow strategy. The Board met by teleconference on January 14 to discuss current and anticipated conditions, as well as operations since its conference call of December 10. While still slightly below average, Lake Erie’s level on January 12 was 13 cm (5.1 in) higher than last year at this time. The level of Lake Ontario was 74.84 m (245.54 ft), which is 28 cm (11 in) above average, and 49 cm (19.3 in) higher than last year at this time. Lake St. Louis and Montreal Harbour are 1 cm ( 0.4 in) above and 5 cm (2 in) below their long term averages and 53 cm (20.9 in) and 134 cm (52.8 in), respectively, above their levels of a year ago. The end of March 2004 levels for Lake Ontario are forecast to be 2 and 32 cm (0.8 and 12.6 in) above average under average and wet water supply scenarios, respectively.

During the last three weeks of December and the first week of January, Lake Ontario outflows were above those specified by Plan 1958-D in accordance with the Board’s strategy to reduce the amount of water stored on Lake Ontario relative to the Plan 1958-D level. The increased outflows allowed the hydropower entities to make efficient use of water. By January 9 there was about 1.4 cm (0.6 in) of conserved water remaining on Lake Ontario. Ice formation in the Beauharnois Canal was essentially complete by January 13, which allowed outflows to be increased slightly. The ice cover has also started to form in the International Section and is expected to progress upstream in the next several days subject to weather conditions. During the next few days it is expected that outflows will be varied to assist the formation of stable ice cover.

The Board considered the following factors (among others) in revising its strategy:

► the above average levels of Lake Ontario;

► the near average level of Lake Erie and below average levels of Lakes Huron, Michigan and Superior as they affect the inflow to Lake Ontario;

► amount of stored water that was reduced from 9.1 cm (3.6 in) in December to 1.4 cm (0.6 in) in January;

► the need to reduce flows below those of Plan 1958-D during ice formation;

► uncertainty regarding ice conditions in the river, snow pack and supplies over the next few months;

► the forecasted Plan 1958-D outflows and levels;

► the impact of over-discharges over the next few weeks on hydropower;

► the expected Plan 1958-D outflows of 6230 cms (220,000 cfs) in January and 6800 cms (240,000 cfs) during the first week of February; and,

► the potential for conserving water during the spring freshet;


The Board agreed to update the strategy as was announced on December 15. The strategy is to further reduce the amount of conserved water on Lake Ontario during the remainder of January, and re-examine the situation by mid-February. Until the Board’s next teleconference, outflows will be determined as follows:

  1. Outflows will generally be in accordance with those specified by Plan 1958-D;
  2. Outflows may be adjusted to facilitate and maintain a stable ice cover;
  3. Following the formation of a stable ice cover, outflows greater than those specified by Plan 1958-D in January will reduce the amount of stored water; and help meet critical hydropower generation needs; and,
  4. Outflows will not exceed 6800 cms (240,000 cfs) in January.

The Board, in conjunction with its staff, will continue to monitor the situation and act accordingly. This information can also be found on the Board web site (see below) and will be updated as required.

The International Joint Commission was created under the Boundary Waters Treaty of 1909 to help prevent and resolve disputes over the use of waters along the Canada-United States boundary. Its responsibilities include approving certain projects that would change water levels on the other side of the boundary, such as the international hydropower project at Massena, New York and Cornwall, Ontario. When it approves a project, the Commission’s Orders of Approval may require that flows through the project meet certain conditions to protect interests in both countries. For more information, visit the Commission’s website at www.ijc.org.

The International St. Lawrence River Board of Control was established by the International Joint Commission, mainly to ensure that outflows from Lake Ontario meet the requirements of the Commission’s Orders of Approval. For more information, visit the Board’s website at www.islrbc.org.

For Release: January 16, 2004


Reg Golding, Ottawa, Ontario (613) 998-1408

John Kangas, Chicago, Illinois (312) 353-4333