The%20Role%20of%20Wetlands%20in%20Nutrient%20Control%20of%20Lake%20Systems

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The Role of Wetlands in Nutrient Control of Lake
Systems

• Mary Ray

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Wetlands

• Provide habitat to animals
• Provide services to local communities
• Filtering drinking water
• - Detaining flood waters
• Acts as a source or sink of pollutants
• As a sink provides nutrient retention

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Nutrients
Decrease in Dissolved Oxygen
Algal growth
Image from Oneplan.org
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Nutrients in Wetlands

• Wetlands remove N via
• Degassing
• Sedimentation
• Nitrification and Denitrification
• Phosphorus
• Compared to N, less is stored in wetlands
• Newly constructed wetlands have better retention
  of P than aged wetlands

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Artificial Wetland at Lake Finjasjön

• Community relies on the lake for
• Drinking water
• Treatment of wastewater effluent released from
  the municipal sewage treatment plant
• Solution for reducing high nutrient levels
  construction of an artificial wetland
• The wetland is one piece of the management
  strategy

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Artificial Wetland at Lake Finjasjön

• In the first year of use the wetland provided
  these results for nutrient control
• Total Phosphorus 25
• Total Nitrogen 32
• Artificial wetland success!

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Lake Victoria, Africa

• Surrounding wetlands used for agriculture, fish
  production, drinking water supply by 30 million
  people

Images from go2africa.com eosnap.com
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Lake Victoria Managing Natural Wetlands

• When managing wetlands for lake benefits, it is
  best to focus on
• Physical structure
• Type of vegetation
• Wastewater flow rate
• Intense management of wetlands is critical for
  preserving the multiple services provided for
  lake health

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Conclusions

• Both natural and artificial wetlands are good at
  retaining nutrients
• Artificial wetlands may replace natural wetland
  sites at full effectiveness 8 16 years after
  construction
• In lake management, it is important to consider
  use of artificial wetlands

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The Role of Wetlands in Nutrient Control of Lake
Systems
References include Annadotter, H., G.
Cronberg, R. Aagren, B. Lundstedt, P. Nilsson
S. Ströbeck, 1999. Multiple techniques for lake
restoration. Hydrobiologia 395/396 77-85.
Loiselle, Steven, A. Cozar, A. Van Dam, F.
Kansiime, P. Kelderman, M. Saunders S. Simonit,
(). Tools for Wetland Ecosystem Resource
Management in East Africa Focus on the Lake
Victoria Papyrus Wetlands. In J.T.A. Verhoeven,
B. Beltman, R. Bobbink, D.F. Whigham (Ed.),
Wetlands and Natural Resource Management, 2006
(pp. 97-121). New York Springer. (Reprinted from
Ecological Studies, 190).