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

Lake Ontario Outflow Strategy
(January 13, 2003)

Precipitation and water supplies were well below average in December for all of the Great Lakes except Lake Erie. Lake Ontario water supplies were below average for the past six months. Montreal Harbour levels and Ottawa River flows set new record lows for December and daily levels at the Port of Montreal were below chart datum. December daily levels at Pointe Claire on Lac St. Louis ranged between 20.48 m and 20.70 m.

Water levels of all the Great Lakes were below their respective December averages and all except Lake Erie are lower than one year ago. On January 7, Lake Ontario was at elevation 74.34 m (243.90 feet), which was 21 cm (8.3 inches) below the average for this time of the year, and 20 cm (7.9 inches) below the level of one year ago. The water levels in Lac St. Louis and Montreal Harbour were about 20.77 m (68.1 feet) and 5.96 m (19.55 feet), respectively. These were 56 cm (22 inches) and 72 cm (28.3 inches) below their respective averages.

The Board discussed these and other conditions in a teleconference on January 8 and decided to update the outflow regulation strategy announced on December 16 with appropriate considerations in the light of anticipated winter operations. That is:


Outflows will be generally as determined by Regulation Plan 1958-D, except for the following deviations:

  1. Flow reductions, or increases, to facilitate ice formation and management in the St. Lawrence River;
  2. Flow reductions to restore water on Lake Ontario to the level specified by Plan 1958-D and to conserve additional water on Lake Ontario. Opportunities to reduce flows may arise during ice management or when Plan flows are greater than the minimum flow limits within Plan 1958-D, and the level of Lac St. Louis is maintained above 20.6 meters. The storage of water on Lake Ontario relative to the level specified by Plan 1958-D will not exceed 5 cm (2 inches).
  3. Flow increases to maintain Lake St. Louis levels above 20.45 m (67.1 feet).
  4. And, provided that the ice conditions in the St. Lawrence River permit, a maximum daily over-discharge of 300 m3/s (10,600 cfs) above the Plan flow may be released as required for the following purposes:

  5. To meet critical hydropower needs, and,
  6. To raise levels at the Port of Montreal to meet critical navigation needs.

The outflow increases for the purposes mentioned above may use the equivalent of a maximum of 8 cm (3 inches) of water from Lake Ontario relative to Regulation Plan 1958-D. As of January 8, the accumulated over-discharges were at 4.8 cm (1.9 inches).

The Board intends to review this strategy in February, at its regularly scheduled monthly meeting, or before if conditions require.

The Board continues to closely monitor the conditions on the Lake Ontario-St. Lawrence River System and will intervene 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 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: January 13, 2003


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

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