1. The Role of Wetlands in Nutrient Control of Lake Systems Mary Ray

2. 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

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

4. 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

5. 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

6. 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!

7. Lake Victoria, Africa Images from go2africa.com & eosnap.com - Surrounding wetlands used for agriculture, fish production, drinking water supply by 30 million people

8. 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

9. 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

10. 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).