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


Lake Ontario Outflow Strategy
(July 26, 2004)

The International St. Lawrence River Board of Control (Board) met on July 21st to review current and anticipated conditions, and decided to continue the strategy that has been in effect since June 9th . Accordingly, outflows will be as determined by Regulation Plan 1958-D, except for the following deviations to meet critical needs;

  • The outflow may be increased to meet critical hydropower needs, to maintain levels above 20.6 m (67.6 ft) at Pointe-Claire on Lake St. Louis, or to allow incoming vessels to reach the Port of Montreal. Any such over-discharges shall be limited to no more than 600 cubic metres per second (cms) (21,200 cubic feet per second (cfs)) per day and 300 cms (10,600 cfs) per week.

The Board considered the following factors, among others, in making its decision:

  • On July 18, Lakes Superior, Michigan-Huron and Erie were 12 cm (4.7 inches), 22 cm (8.7 inches) and 3 cm (1.2 inches) below average, respectively. They were expected to remain below average, or near average in the case of Lake Erie, throughout the next 6 months.
  • The level of Lake Ontario reached its seasonal peak in early June, at 75.16 m (246.59 ft). The level remained near that value until about mid June, when it began its slow seasonal decline.
  • On July 18, Lake Ontario was at elevation 75.10 m (246.39 ft). This was 10 cm (3.9 inches) above average, and 5 cm (2.0 inches) above last year. This level is 27 cm (10.6 inches) below the upper regulation limit, and 95 cm (37.4 inches) above the lower regulation limit that applies during the navigation season.
  • If water supplies to Lake Ontario for the next several months are near the average amount, the Lake level should follow its normal pattern of season decline, and reach a level of approximately 74.47 m (244.32 ft) by the end of December. That level would be approximately 7 cm (2.8 inches) below the average level for that time of year, and would be well below the upper regulation limit and well above the lower limit. If very wet conditions prevail, December’s water level could be a few centimetres above the average. On the other hand, if conditions are very dry, the level could decline to 15 cm (5.9 inches), or more, below average. In either of these extreme cases, the level will remain well within the upper and lower limits of regulation. If the regulation plan is followed strictly, the risk of going above the upper regulation limit or below the lower regulation limit is estimated to be 1% or less.
  • Conditions downstream in Lake St. Louis and Montreal Harbour on July 18 were as follows: Lake St. Louis was 12 cm (4.7 inches) above average and 43 cm (16.9 inches) above last year. Montreal Harbour was 14 cm (5.5 inches) above average and 80 cm (31.5 inches) above last year.
  • The total accumulated water on Lake Ontario relative to the Plan 1958-D level was about 4 cm (1.6 inches).

 

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’s web site (see address below), where it is 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: July 26, 2004


Contacts:

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

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