Wetland
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Wetlands
Green InfrastructureStormwater wetlands typically consists of open water, shallow marsh, and semi-wet areas that are located just above the permanent water surface.
Maintaining Stormwater Wetlands
Routine maintenance should be performed on stormwater wetlands. During the first year that the wetland is built, maintenance may be required at a higher frequency to ensure proper functionality. For more information on wetland vegetation, see [link to Appendix D: Planting and Soil Guidance].
In addition to routine maintenance, stormwater wetlands have seasonal and intermittent maintenance requirements. During the winter, wetlands should be inspected to make sure that materials used to de-ice surroundings stay out of the practice. Planting material should be trimmed in the winter, when plants are dormant.
After a large rainstorm, keep drainage paths, both to and from the area, clean so that water can be properly flow into the wetland.
If the wetland has received a significant amount of sediment over a period of time, then the sediment at the bottom of the forebay or wetland may need to be removed. Sediment excavated from wetlands that are not stormwater hotspots are not toxic and can be disposed through land application or landfilling.
Fertilizers and pesticides should be used sparingly and only if necessary.
Embankment of the wetland should be inspected regularly for trees and animal activity. Trees growing on the top or sides of the embankment should be removed. Animals can burrow holes weakening the structure of the embankment.
Common Stormwater Wetland Issues
Here are some of the common problems to be aware of when maintaining a vegetated filter strip. They include, but are not limited to, the following:
- Sediment build-up
- Clogging in the inlet and outlet structure
- Establishing vegetation within the wetland area
- Maintaining proper pH levels for plants
- Pruning and weeding to maintain appearance
- Mosquitoes breeding in practice
Some types of vegetation in wetlands can create an environment for mosquitoes to breed. Keep the practice free of trash and place fish such as mosquitofish in the wetland are options to help control mosquitoes. It is also likely that chemicals may be required as well.
Stormwater Wetland | |
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As needed (following construction) |
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Monthly |
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Annually |
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Semi-annually (quarterly during the first year) |
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Annually |
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5 to 7 years or after 50% of the total forebay capacity has been lost |
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10 to 20 years or after 25% of the permanent basin volume has been lost |
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