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

Lake Ontario Outflow Strategy
(November 17, 2003)

The Board reviewed conditions in the Lake Ontario - St. Lawrence River basin on November 12 and noted some improvements since its last review on October 20 (see Board release of October 27). The level of Lake Ontario on October 11 was 74.62 m (244.82 ft.), which is 5 cm (2.0 in.) above average, and 25 cm (10 in.) higher than last year at this time. As a result of the Board’s strategy to conserve water on the Lake for future critical needs, there are approximately 5 cm (2 in.) of water conserved on the Lake, relative to the level that would have occurred if Plan 1958-D had been followed exactly. Lake St. Louis and Montreal Harbour are 54 cm (21 in.) and 70 cm (28 in.), respectively, above their levels of a year ago.

As a result, the Board agreed to maintain the same strategy as was announced on October 27. The long-term strategy, in consideration of the continued below-average levels on the upper Great Lakes (Superior, Michigan, and Huron) and within current system constraints, is to ensure that enough water is in Lake Ontario to meet future critical needs. The short-term strategy is to meet critical needs and, as opportunities arise, conserve additional water for future critical needs. To accomplish this, outflows will be determined by Regulation Plan 1958-D, except for the following deviations to meet critical needs or to conserve water:

  1. Flow increases to maintain Lake St. Louis level at Pointe Claire above 20.60 m (67.6 ft.) and the level of Lake St. Francis at Summerstown above 46.58 m (152.82 ft.);
  2. Flow increases to meet critical hydropower needs and to raise levels at the Port of Montreal for critical navigation needs at a maximum weekly over-discharge of 300 m3/s (10,600 cfs) and no more than a maximum daily over-discharge of 600 m3/s (21,200 cfs) above Plan flow (a flow change of 300 m3/s will result in a change in level at Montreal of about 10 cm (3.9 in.) and, after a week, a change in Lake Ontario level of about 1 cm (0.4 in.)); and,
  3. Flow decreases to conserve up to 10 cm of water on Lake Ontario, at a maximum weekly under-discharge of 300 m3/s (10,600 cfs), as opportunities arise.

The Board, in conjunction with its staff, will continue to monitor the situation and act accordingly. The Board intends to review this strategy at its next scheduled Conference Call on December 10.

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: November 17, 2003


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

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