Managing the St. Lawrence

Managing the St. Lawrence


The St. Lawrence is an enormous system that
has undergone countless structural changes since the 19th century. Most of Quebec’s population lives in the St.
Lawrence River Valley and is concerned about river management. “Our top concern for the entire territory
we have here is what we call coastal hazards, which encompasses everything concerning the
erosion of the banks and the swallowing up of land by the St. Lawrence.”
Françoise Bruault, Director, Sud de l’estuaire ZIP Committee While some people want the water levels to be stable, others maintain that fluctuations
play an important role. After the sizeable Moses Saunders hydroelectric station was built
in Cornwall, the International Joint Commission set up an organization to oversee the management
of the St. Lawrence water level. “The International St. Lawrence River Board
of Control is part of the International Joint Commission, a bi-national organization—
Canadian and American—that manages the waters that mark the boundaries between these two
countries.” Philippe Morel, Co-chair, International St.
Lawrence River Board of Control, and Regional Director General, Environment Canada In the past, spring runoff of the Great Lakes
and the Ottawa River caused major fluctuations in the water level, which resulted in flooding
in several places. The construction of the Moses-Saunders dam, originally designed for
hydroelectric production and commercial navigation, allowed the St. Lawrence water level to be
better managed, while taking into account the needs of different interest groups. “One of the important aspects that we take
very seriously is civil safety. In other words, in making decisions, we’ll take into account
the fact that there may be major spring runoff in certain parts of the river at times. So
we’ll reduce the water level upstream to ensure there’s no flooding, in Montreal for example,
or elsewhere, during spring runoff. Philippe Morel, Co-chair, International St. Lawrence
River Board of Control, and Regional Director General, Environment Canada Environment Canada’s role on the International
St. Lawrence River Board of Control consists of providing environmental forecasting services
in compliance with orders from the International Joint Commission. These forecasts, produced by digital modelling,
make it possible to simulate the St. Lawrence’s evolution. “We use absolutely all the observations that
exist in the environment—air temperature, humidity, precipitation, water temperature—absolutely
all the variables used to create the initial conditions are incorporated into the models.
Once we have that, we can initiate and do a complete environmental forecast.”
Pierre Pellerin, Manager, Environmental Numerical Weather Prediction Research, Environment Canada Modelling allows us to predict fluctuations in the water levels and flows, for example,
as well as temperature and water quality variations, ice flow, the breadth of marshes and swamps,
changes in fish populations, and how far agricultural or municipal pollutants spread. “Integrated modelling tools help us respond
to complex issues such as regulating the Lake Ontario-St. Lawrence system, evaluating the
impact of contaminants on the river’s ecosystem, and responding to environmental emergencies
that involve the spilling of floating or soluble pollutants.” André Bouchard, Manager, Hydrology
and Ecohydraulics Section, Environment Canada “The development of the environmental forecasting
system has been very important. It allows us to better understand the St. Lawrence and
to better manage it.” Pierre Pellerin, Manager, Environmental Numerical Weather Prediction
Research, Environment Canada “The St. Lawrence ecosystem is one of the
most amazing ecosystems in Canada. It’s the ecological lungs of Quebec and contains a
tremendous, rich diversity. It has urban environments as well as environments that are still very
wild. It’s an ecosystem that we need to learn to appreciate and to benefit from, but we
also need to learn to protect and to preserve it for future generations.” Philippe Morel, Co-chair, International St.Lawrence River Board of Control, and Regional
Director General, Environment Canada

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