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


Lake Ontario Outflow Strategy
(June 13, 2003)

With the recent wet spell, the water levels on all of the Great Lakes increased more than average in the month of May, but they all continue to be lower than they were a year ago. Lake Ontario rose 27 cm (10.6 in) in May, compared to an average rise of 8 cm (3.1 in.), and, at a level of 75.13 m (246.49 ft.) is now 8 cm (3.1 in.) above its average for this time of year. Montreal Harbour levels improved in May and were well above datum throughout the month. In light of the higher than average precipitation experienced during May the Board decided to suspend the conservation of additional water on Lake Ontario effective June 7th. As of that date, about 4.2 cm (1.7 in.) of water had been stored.

Forecasts indicate that the lake could rise about another 3 cm (1.1 in.) under continued above-average precipitation conditions, but would stay about at its current level throughout the rest of June under average precipitation conditions.

The Board discussed these and other conditions on its teleconference on June 12 and updated the outflow regulation strategy announced on May 22. In consideration of the continued below average levels on the upper Great Lakes, the long-term strategy is to retain as much of the water conserved on Lake Ontario as possible, for critical needs later in the year, and within current operational constraints. Through the second week of July, outflows will generally be as determined by Regulation Plan 1958-D except for the following deviations.

a) Flow increases to maintain Lake St. Louis levels above 20.6 m (67.6 ft) and the level of Lake St. Francis at Summerstown above 46.58 m (152.82 ft).

b) 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 /day (21,200 cfs/day) 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 inches) and, after a week, a change in Lake Ontario level of about 1 cm (0.4 inch.).

The Board intends to review this strategy at its June 20th meeting and in July at its regularly scheduled monthly teleconference. The Board, in conjunction with its staff, continually monitors the conditions on the Lake Ontario-St. Lawrence River System.

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: June 13, 2003


Contacts:

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

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