Lake Erie Water Quality

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Lake ErieWater Quality

• 1950s - 2000s

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Problem
Model Method
Assessment
Implementation
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Lake Erie June 8, 2005
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Lake Erie

• 12th Largest lake in the world
• Detroit River from Lake Superior, Michigan, Huron
  and represents 95 of current inflow
• Outflow Niagara River to Lake Ontario
• Retention time (shortest) 2.6 years

64 m
7.4 m
29 m
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Lake Erie The Eutrophication Story

• Eutrophication (Eu truly , trophic
  nutritious) Rich in organisms and organic
  material.

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The Results

• 1950-60s -- Explosion of blue-green algae
  population
• 1970s -- much of central basin was anoxic and
  hypoxic due to decaying algae in late summer
  months
• "Dead Sea of North America
• Stress to commercial and sport fisheries
• Beach were closed

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The Source Problem-Phosphorus

• Sewage and Industrial Waste
• Introduction of phosphorus-based detergents post
  WWII.
• 9 million municipal population
• 2 million septic tanks population
• Agricultural Activity - Both Canada and US
• Drainage vast coastal wetlands
• Increased sediment runoff from tilled lands
• Increase phosphorus and nitrogen based fertilizer
  use

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The Solution

• International Joint Commission (IJC) determined
  that eutrophication was occurring as a result of
  the high phosphorus loading entering the lake in
  the 1950 and 1960s.
• 7.5 Billion spent since 1972 to bring into
  compliance with 1.0 mg/L phosphorus abatement
  program.
• Goal is 11,000 metric tons/year phosphorus
• Reduce the phosphorus in household detergents.

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Phosphorus Conceptual Model
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Living Organic Phosphorus Stock (L)
input
output
     
L Living Stock I Inorganic Stock
a Death Rate b Decomposition rate c
Utilization (uptake) rate
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Dead Organic Phosphorus Stock (D)
input
output
     
   
L Living Stock I Inorganic Stock D Dead
Stock
a Death Rate b Decomposition rate c
Utilization (uptake) rate
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Inorganic Phosphorus Stock (I)
input
output
     
     
   
L Living Stock I Inorganic Stock D Dead
Stock
a Death Rate b Decomposition rate c
Utilization (uptake) rate
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Steady - State Conditions Exchange of mass
between different reservoirs remains constant
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Stella Model
a Death Rate b Decomposition rate c
Utilization (uptake) rate
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STELLA Parameters
a 0.25 Rate constant for transformation of
phosphorus in living biomass into dead organic
matter. units 1/days
b 1/20 Rate constant for conversion of
phosphorus in dead organic matter into inorganic
form. units 1/days
c 1/0.4 Rate constant for uptake of inorganic
phosphorus by living organisms. units
(1/days)(liter/micromol)
D 0.5 Phosphorus in dead organic matter in
micromol/liter.
I 0.5 Phosphorus in inorganic form in
micromol/liter.
L 0.3 Phosphorus in living biomass in
micromol/liter.