Les alumineries au Qubec

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The presentation

• What is a healthy lake?
• What are the major threats?
• What is eutrophization?
• What can be done?

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Characteristics of a healthy lake

• Clear oxygenated water right to the bottom
• Few aquatic plants
• Lake trout and brook trout are typical

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Major threats to the health of our lakes

• Acid rain

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Major threats to the health of our lakes

• Acid rain
• Introduction of exotic species

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Major threats to the health of our lakes

• Acid rain
• Introduction of exotic species
• Eutrophization

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What is eutrophization?

• The accelerated development of plants in a lake,
  especially microscopic algae (plankton).
• Some speak of the aging of the lakes.

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Impacts of eutrophization on use

• Water less clear
• Less oxygen in deeper parts
• More aquatic plants
• Increased risk of blue algae

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Impacts of eutrophization on use

• Quality decline
• Swimming
• Fishing
• Nautical sports
• Aesthetics
• Less quality of life
• Diminished tourist attraction
• Lost

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The aging of the lake is a natural process, so
why bother with it?

• Because man accelerates the process.
• Nature several thousand years
• With human influence several tens of years

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What causes eutrophization?

• When water is enriched like in a garden to which
  fertilizer has been added
• One element in particular phosphorus

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Sources of phosphorus

• Natural
• Precipitations
• Forest run off, marshes, etc.
• Erosion
• Human activities
• Septic installations
• Deforestation, agriculture, roads, etc.
• Increased erosion
• Spreading of fertilizer, manure, etc.

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A lake is its watershed

• All activities in the watershed of a lake results
  in increased levels of phosphorus and contributes
  to eutrophization.
• A lake reacts to the sum total of everything
  originating from its watershed

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Eutrophization can be prevented

• A lake eliminates a portion of the phosphorus it
  receives
• Phosphorus levels less than the lakes absorption
  capacity (its support capacity) are tolerable
• This support capacity can be calculated

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Eutrophization is reversible

• Reduce phosphorus levels

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Taking preventive action against eutrophization
means reducing the amount of phosphorus entering
the lakes

• Action can be
• Individual
• Collective

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Individually, this means reducing our ecological
print

• Build and adequately maintain septic
  installations
• Reduce the use of phosphates (detergents, etc.)
• Reduce water consumption
• Protect the buffer area
• Do not fertilize in agriculture, management of
  manure, livestock and fertilization plants
• Avoid erosion
• No needless deforestation
• Minimize surface sealing

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Collectively

• Enforce existing regulations
• Land-use planning must be based on lake support
  capacity

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To conclude

• We can protect the health of our lakes.
  Its up to us to decide to do so
• Doing nothing or not doing enough also
  amounts to making a decision, because by so
  doing, we are agreeing to losing a major portion
  of our natural capital