FINAL REPORT - International Joint Commission

Environment
• Although construction of the regulation and navigation structures made dramatic changes in the
environment of the St. Lawrence River, the lower river is less sensitive to changes in water level
regulation than Lake Ontario and the upper river. This is because regulated releases are very diverse
and span an even greater range than natural releases. The hydrology and hydraulic responses are
different in the lower St. Lawrence River than on Lake Ontario because the lower river hydrology is
influenced not only by the outflows from Lake Ontario, but also by the Ottawa River flow and by
local tributaries.
• Current muskrat housing density above the Moses-Saunders dam is extremely low, so any improvement
tends to create large positive ratios for this performance indicator. Muskrats constitute a very important
part of both the structure and function of wetlands and they therefore represent much more than just
their own species. As a result, muskrat housing density is an important environmental indicator to take
into consideration.
• The current regulation plan (1958-DD) has stabilized lake levels, creating a more narrowly defined
transition from submerged to upland plants, thus reducing the diversity of plant types along the shore
and lowering the populations of animal species who fed on and lived in the environments harmed by
more stable water levels.
• Indications are that the current regulation plan (1958-DD) has had an effect on the productivity of
several species at risk.
FINAL REPORT
The Shared Vision Model
The Shared Vision Model is the name of the computer model developed in the context of this Study to
integrate the results from each of the technical work groups in one place. With this Model various
regulation plans could be run through an evaluation process and the results compared between interests
and locations. The Shared Vision Model connects all Study research to the guidelines the Study Board
developed to identify the best alternative plans, and it integrates plan formulation and evaluation so that
new regulation plans can be designed and immediately evaluated. The fact that specific mathematical
connections had to be made between research products and the questions the Study Board wanted to
address helped ensure that research funding was well spent and that important questions did not go
unanswered. The Shared Vision Model creates a hypothetical link between the levels and flows produced
by a regulation plan and the impacts of those levels and flows. The Shared Vision Model was built from
scratch by the entire Study Team, enabling everyone involved to understand how actions taken to affect
one part of the system or one interest affect all other stakeholders.
The Shared Vision Model developed for this study is actually composed of a pyramid of four models used
to produce estimates of plan performance. They include the STELLA model, with dynamically linked Excel
input files, the Flood and Erosion and Prediction System (FEPS), the St. Lawrence River Model (SRM)
and the Integrated Ecological Response Model (IERM). The STELLA portion includes all of the system
hydrology and all of the performance indicator relationships to water levels and flows for recreational boating,
commercial navigation, hydropower, municipal. industrial and domestic water uses and lower St. Lawrence
River flooding. FEPS estimates the potential flood, erosion and shore protection maintenance impacts on
Lake Ontario and the upper St. Lawrence River. The St. Lawrence River Model (SRM) calculates the
impacts of erosion and shore protection maintenance on the lower St. Lawrence River coastal interests.
The Integrated Ecological Response Model is the environmental wing of the Shared Vision Model and
calculates expected responses of environmental performance indicators to a regulation plan. The Control
Panel and Data Warehouse are Excel files that store and feed data to the other models. The Board Room
is an Excel file where all plan results are presented using tables and graphs.
Options for Managing Lake Ontario and St. Lawrence River Water Levels and Flows
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