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

Lake Ontario Outflow Strategy (Update)
(October 10, 2003)

The Board reviewed conditions in the Lake Ontario-St. Lawrence River basin on October 8 and found little change from conditions at the time of its last review on September 22 (see Board release on September 30). As a result, the Board agreed to maintain the same strategy as was announced on September 30. The long-term strategy, in consideration of the continued below average levels on the upper Great Lakes and within current system constraints, is to ensure that enough water remains in Lake Ontario to meet critical needs later in the year. The short-term strategy is to retain as much as possible of the water already conserved on Lake Ontario. To accomplish this, outflows will generally be as determined by Regulation Plan 1958-D into October, except for the following deviations:

  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.).

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 meeting on October 21.

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.


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

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