FINAL REPORT - International Joint Commission

ANNEX 3
OntRip3: Plan Designed for Coastal Property Owners
Objectives
Plan OntRip3 is a plan developed specifically to minimize flood and erosion damages to shore property,
while also taking into consideration the other interests in the Lake Ontario–St. Lawrence system, to try to
attain a riparian-focused plan with overall net benefits. (Although OntRip3 did reduce coastal damages
compared to Plan 58-DD, it did not meet the goal of doing so without increased overall losses.)
Approach
The OntRip3 plan is based on the benefits-balancing approach used to develop Plan D + . It considers the
same major interests in the system from Lake Ontario downstream to Lac St. Pierre that are listed in the
Plan D + description found in this document. The reader is directed to review that description to obtain an
understanding of the methodology applied in OntRip3. OntRip3 also uses the same forecast procedures
and outflow constraints as Plan D + . OntRip3 uses the same benefits scoring relationships as Plan D + , with
the important exceptions of the Lake Ontario target level and the score for deviations in level from the target
level. In addition, OntRip3 does not include the feature, contained in Plan D + , that occasionally shifts the
Lake Ontario target level to try to induce inter-annual fluctuations in the growing season level.
Benefit Score Curves
With the exception of the Lake Ontario target level, OntRip3 uses the same benefit scoring relationships,
or curves, as used within Plan D + . Only the relationships that differ from Plan D + are included here.
The other relationships are described in the Plan D + section. The Lake Ontario target level used in OntRip3
is shown in Figure B-30 along with the normal target level used in Plan D + . The OntRip3 target level is
lower and has a somewhat different seasonal variation than the Plan D + target level.
Level (m)
Level (ft)
Figure B-30: OntRip3 Lake Ontario target level and Plan D + normal target level
208 Options for Managing Lake Ontario and St. Lawrence River Water Levels and Flows