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

Lake Ontario Outflow Strategy
(May 23, 2002)

Water levels on all of the Great Lakes have risen more quickly than average thus far in May. Lake Superior, Michigan, and Huron remain below average, but Lakes Erie and Ontario are 3 cm (1 inch) and 22 cm (9 inches), respectively, above average. The increase in levels is in response to greater than average precipitation amounts in April and May.

In response to these changing conditions, the International St. Lawrence River Board of Control (Board) has decided to modify the regulation strategy announced on April 15. Effective May 18, outflows will be up to 150 cubic meters per second (cms, 5,300 cubic feet per second, or cfs) greater than called for by the regulation plan, Plan 1958-D. This overdischarge, which is subject to water levels in the Montreal area, will reduce the 7.9 cm (3 in.) of water currently held in reserve on Lake Ontario by about 0.5 cm (0.2 in.) per week and will continue until either Lake Ontario has peaked, or 2 cm of the reserved water has been released. This would leave 5.9 cm (2 in.) of reserved water for critical needs of downstream navigation and power generation later this year. Downstream, Lake St. Louis is close to its flood alert level due to high Ottawa River flows, combined with the Lake Ontario outflow. Montreal Harbour is about 2 meters (6.5 feet) above datum.

The Board intends to review this strategy in early summer, or before if conditions require.

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 Commissionís Orders of Approval may require that flows through the project meet certain conditions to protect interests in both countries. For more information, visit the Commissionís 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 Commissionís Orders of Approval. For more information, visit the Boardís website at www.islrbc.org.

For Release: May 23, 2002


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

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