FINAL REPORT - International Joint Commission

FINAL REPORT
Introduction
Lake Ontario receives its water from the four other Great Lakes as well as from drainage from its local
watershed, and it discharges water into the St. Lawrence River. In the 1950s, Canada and the United States
built the St. Lawrence River Hydropower Project, including a dam stretching across the St. Lawrence River
from Massena, New York, to Cornwall, Ontario. The International Joint Commission (IJC) issued “Orders
of Approval” for the project in 1952 and supplementary orders in 1956. The Orders established criteria
for the operation of the system and also established a Control Board to develop and implement plans of
regulation to meet the orders. A series of plans was investigated and implemented, and in 1963, a new
plan called “1958-D” was approved and put into use. The plan consists of rules for making releases from
the lake every week based on recent water supplies to the lake, how high the lake is, the time of year,
ice conditions, Ottawa River flows, river stages, and a series of flow limits which bound other rules. The
Orders of Approval allow the Control Board to deviate from the written plan, with Commission approval,
particularly under extreme high and low water supply conditions. The Control Board has also been granted
authority to institute emergency and discretionary deviations, as detailed later in this report. The Control
Board has often deviated from the plan to meet the intent of the Orders of Approval and provide benefits to
affected interests. These deviations have been necessitated partly by the changing needs of the system
and partly by the wetter and drier supply conditions experienced since 1960 as compared with the period
from 1860 to 1954, which the designers used in the development of Plan 1958-D.
From time to time, the International Joint Commission considered new plans in an attempt to better meet
the criteria in the Orders of Approval or to provide additional benefits to affected interests. The Great Lakes
Levels Reference Study (1993) recommended a revision and updating of Plan 1958-D. Subsequently,
plans (e.g., Plan 1998) were developed by the Control Board but not implemented by the Commission
because they did not adequately accommodate environmental concerns or recreational boating needs and
there was a lack of information on impacts on other interests.
The International Lake Ontario-St. Lawrence River (LOSLR) Study was designed to address those
shortcomings. Unlike the Levels Reference Study, which addressed water management issues on all the
Great Lakes, the LOSLR Study focused only on water level changes and flow regulation on Lake Ontario
and the St. Lawrence River with the existing dam and other water control structures.
Challenges and Opportunities
None of the previous attempts to revise the regulation plan for Lake Ontario has been as comprehensive
and detailed as this Study. Previous evaluations considered changes to the regulation techniques –
modifying outflow limitations and procedures. The Lake Ontario-St. Lawrence River Study approach was
significantly different in that an extensive public involvement program played a key role in the development
and selection of more comprehensive options. The study conducted a comprehensive evaluation of plan
metrics, which are the basis for the development and evaluation of alternative operating plans. It relied on
Options for Managing Lake Ontario and St. Lawrence River Water Levels and Flows
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