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The Role of Wetlands in Nutrient Control of Lake Systems. Mary Ray. Wetlands. Provide habitat to animals Provide services to local communities: Filtering drinking water - Detaining flood waters Acts as a source or sink of pollutants
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The Role of Wetlands in Nutrient Control of Lake Systems Mary Ray
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
Nutrients Decrease in Dissolved Oxygen Algal growth Image from Oneplan.org
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
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
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!
Lake Victoria, Africa • Surrounding wetlands used for agriculture, fish production, drinking water supply by 30 million people Images from go2africa.com & eosnap.com
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
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
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).