FINAL REPORT - International Joint Commission

ANNEX 2
Figure C-8: Map of downstream coastal damages (average annual 1958-DD stochastic by
regional county municipality) $US
The FEPS and SRM run as separate components of the Shared Vision Model. An executable version of the
FEPS was developed to allow for quick analysis of alternative plans and was later modified to allow for the
running of the full 50,000-year stochastic supply sequence. Results from the historical SRM evaluations
showed little difference among plans. Evaluations for four stochastic and four climate change scenarios
confirmed this, so the SRM was not modified to run through the 50,000-year simulation. Instead, the final
values for downstream shore protection costs are an average of the historical and four extreme 101 stochastic
series results.
Summary of Key Findings
• The timing of high water levels during the spring and fall can have a considerable impact on plan results.
Plans that tend to keep Lake levels lower in the late fall and early spring will result in conditions more
favourable to the riparian interest.
• Regulation plans in which the annual peak water level consistently occurs in the June, July, and August
period will generally minimize coastal impacts.
• The shore protection maintenance performance indicator was the most sensitive to changes in a
regulation plan on Lake Ontario because shore protection maintenance is very sensitive to the impact
of waves, and postponing the maintenance of existing shore protection can be economically beneficial,
especially to south shore residents.
Options for Managing Lake Ontario and St. Lawrence River Water Levels and Flows
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