Lake Ontario-St. Lawrence River Flows Increased After Stable Ice Cover Forms
Lake Ontario-St. Lawrence River Flows Increased
After Stable Ice Cover Forms
Outflows from Lake Ontario have increased steadily since January 31, 1997, when formation of a stable ice cover on the St. Lawrence River was nearing completion. Under the winter operations provision of the International Joint Commission's Orders of Approval, the outflows will be as high as possible without causing downstream flooding.
Formation of an ice cover, as complete and stable as possible, helps to prevent underwater ice blockages that can restrict flows.
The Commission's International St. Lawrence River Board of Control had reduced flows to allow ice cover formation. As recently as January 28, 1997, flows were reduced to 6,500 cubic meters per second or cms (230,000 cubic feet per second or cfs) to aid ice cover formation above Iroquois Dam, the last critical section of the St. Lawrence River to form ice.
Since January 31, 1997, the Board of Control has increased Lake Ontario outflows by approximately 300 cms (10,600 cfs) per day. The present outflow is 8,100 cms (286,000 cfs). The Board of Control will carefully monitor conditions that affect levels and flows on Lake Ontario and the St. Lawrence River, including the condition of the ice cover.
On January 17, 1997, the Commission invoked criterion (k) of its Orders of Approval to provide all possible relief to shoreline property on Lake Ontario and the St. Lawrence River from the Thousand Islands to past Montreal. Criterion (k) will provide the authority to continue higher outflows, which will likely still be needed once winter operations are over.
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 hydropower project near Cornwall, Ontario and Massena, New York. The Commission established the International St. Lawrence River Board of Control to ensure that outflows from Lake Ontario meet the requirements of the Commission's Orders. The Board also develops regulation plans and conducts special studies as requested by the Commission.