FINAL REPORT - International Joint Commission

FINAL REPORT
• All performance indicators should be constructed so that a positive number means that an interest
gains net benefits from a plan and a negative number means that an interest loses net benefits from
a plan, relative to Plan 1958-DD.
• Given the Study Board decision to avoid formulaic translations of environmental impacts to economic
metrics, the Environmental Technical Work Group should develop performance indicators based as
closely as possible on the economic concept of net economic benefits.
The Study Board’s primary method of comparing the economic performance of the plans was based on
average annual net benefits, measured in millions of U.S. dollars. Its primary method of comparing the
environmental performance of the plans was to compare the ratios of each plan’s performance indicator
scores to the scores for Plan 1958-DD.
The Study Board relied heavily on the expert advice of the Environmental Technical Work Group in determining
the best mix of environmental performance indicator scores (no plan improved all scores). At the request
of the Study Board, the Work Group supplied error margins for their ratios to assist the Study Board in
eliminating the noise and concentrating on those performance indicators that were truly impacted by a plan.
For most environmental indicators, a ratio between 0.90 and 1.10 was generally taken to mean there was no
significant change from 1958-DD, while anything above 1.10 was better and anything below 0.90 was worse.
In addition, the Study Board requested an overall index, and while the Environmental Group cautioned
against the use of this index as an oversimplification of the results, the overall environmental index did
assist the Study Board in understanding the significance of the environmental results. Information on the
overall environmental index and how it was developed can be found in the Environmental Technical Work
Group section of Annex 2 to this report.
The Study Board had considerable confidence in using the economic performance indicators to determine
which plans are better for the various sectors. Many members of the Study Board placed greater emphasis
on minimizing losses to any interest or region than on maximizing overall benefits for all interests and
regions, which could create large losses in one or two areas.
Economic impacts were first developed using the historical water supply sequence, but the final results
relied on discounted average annual benefits based on 495 samples of 101 years from the 50,000 years of
stochastically generated water levels. This gives the Study Board more confidence that plan rankings are
not just a function of the past 101 years of the hydrologic record. This is particularly important for the
coastal erosion and shore protection maintenance performance indicators since these have serial dependence,
and true benefit comes not from avoiding damage but from delaying it. This approach estimates when erosion
or damage will occur, discounting future damages so that the later the damage the less important it is.
The Study Board also used water levels and flows produced by each plan to supplement their plan rankings
based on performance indicators, including information on average, maximum and minimum levels
provided by plans, timing of annual cycles, how plan hydrology differed in wet and dry extremes, and
timing, magnitude and frequency of flow releases. This helped the Study Board to understand how a plan
was reacting and adjusting to supplies. A number of Study Board members also found it easier to assess
plans directly in relation to their levels and flows.
In summary, this Study has produced more and better data and information by which to evaluate plans
than has ever been available before. With the information integrated into a Shared Vision Model, it has
allowed for numerous iterations of plan development in attempts to reach the best balance between
interests and locations. While there will always be gaps in understanding, the Study Board is confident
that the information developed and analyzed is sufficient to ensure the best selection of regulation plans
for managing the Lake Ontario-St. Lawrence River system.
28 Options for Managing Lake Ontario and St. Lawrence River Water Levels and Flows