FINAL REPORT - International Joint Commission

Short-term deviations can be defined as and considered for:
Emergencies: dam or dike failures, hydropower plant or system failures and declared emergencies
such as occurred during the 1998 ice storm or the August 2003 blackout, oil spills near the dam, and
operations to free a grounded ship near the dam, etc.;
FINAL REPORT
Ice Condition Operations: within-the-week flow variations necessitated by and based on actual river
ice conditions, consistent with the intent of the rules of the plan;
Forecast Adjustments: within-the-week flow variations if local inflows from the Ottawa River or other
downstream tributaries change markedly from those forecasted when the weekly plan flows were
established, and the effect of plan flows on river interests and processes changes significantly from the
intent of plan rules.
“Immediate response” authority for short-term emergency and ice condition operations has been divested
to and is currently exercised by the Control Board’s Regulation Representatives.
The Study Board recommends that short-term discretionary deviations continue to be allowed to address
emergency events. These deviations should be restricted to short-term actions to benefit one or more
interest and, although the intent is to do so without adversely affecting others, it may be necessary under
emergency circumstances to cause small harm to some in order to avoid larger harm to others. This is a
judgment call reviewable by the Control Board and Commission.
The Study Board also recommends that flow adjustments within the week due to changing ice conditions
or departures from forecasted inflows to the River downstream of the Moses-Saunders Dam should not be
treated as deviations if they are applied in order to maintain the intent of the plan rules.
All the new plans have rules that take into account ice management, downstream flooding and, in some
cases, low flows. However, the plan flow computed for the week based on initially forecasted conditions
for the coming week may no longer conform to the intent of the rules of the plan if a significant and
unpredicted change occurs in ice conditions or downstream inflows within the week. In such cases, the
flow is adjusted within the week. Since these within-the-week changes are made to better conform to plan
rules given the occurrence of marked changes within the week, they should not be considered deviations
from the plan.
Short-term discretionary deviations can also be defined as and considered for:
Interest-Specific Deviations: within-the-week flow variations for several hours or a day or so,
for example to:
• meet short-term peak hydropower capacity needs;
• allow an ocean-going ship to reach Montreal if levels are below forecasts provided during ship loading
at its departure port;
• accommodate a recreational boat haul-out weekend;
• meet a short-term environmental need on the River, i.e. defer a reduction in river flow to maintain
steady water levels during a fish spawning period; or
• maintain minimum draft conditions in the St. Lawrence Seaway upstream of Montreal.
Options for Managing Lake Ontario and St. Lawrence River Water Levels and Flows
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