Constructed wetlands use natural processes involving vegetation, soils, and associated microbial assemblages to improve water quality. They are designed and engineered to treat wastewater and manage runoff. Constructed wetlands are tailored to respond to site and community specific needs. The uses of constructed wetlands can contribute to one or all of the following: improved water quality, stormwater management, sewage treatment, public access points, and habitat for wildlife.
- Primarily constructed on municipally-designated land and positioned outside floodplains and floodways to prevent harm to existing natural wetlands and other hydrologic features
- Site considerations include the substrate and soil chemistry, hydrological and geological features, existing vegetation and habitat for endangered and threatened species
- Standing water in constructed wetlands may contribute to thermal pollution and downstream warming. This may preclude their use in areas where sensitive aquatic species live
- Planning considerations include land-use and zoning approvals, and additional safety precautions to mitigate potential safety and health impacts
- Annual checking of inlet and outlet structures
- Removal of litter and other debris to ensure no blockage of water flow
- Removal of excess sediment buildup to maintain water flow and drainage, as needed
- Maintain general appearance of vegetation, as desired
- Monitor wildlife to ensure animals are healthy and do not negatively impact the wetland
- Costs vary depending on context and scale of the proposed constructed wetland
- Installation costs range from $6,000 to $300,000 per hectare, with an average of $100,000
- Average maintenance costs are less than $1,500 per hectare a year and can be more cost effective than atreatment options
- Wetlands in the Greenbelt typically provide flood protection services worth over $10,000 per year
(Costs source: Canada Mortgage and Housing Corporation)
Constructed Wetlands by Sustainable Technologies Evaluation Program.
Resources on Constructed Wetlands by United States Environmental Protection Agency.
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