Difference between revisions of "Wetlands"
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Jenny Hill (talk | contribs) m (→Design) |
Jenny Hill (talk | contribs) m (→Design) |
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|Active Storage Depth | |Active Storage Depth | ||
|Storage/flow control, sustaining vegetation | |Storage/flow control, sustaining vegetation | ||
|style="text-align: left|Maximum 1. | |style="text-align: left|Maximum 1.0 m for storms < 10 year event | ||
|- | |- | ||
|Side Slopes | |Side Slopes |
Revision as of 01:14, 29 September 2018
Overview[edit]
Wetlands are an ideal technology for:
- Text A
- Text B
Type A | Type B | Type C |
---|---|---|
Surface water | Minimal Any surface flow can be slowed with check dams |
Ponding is encouraged with check dams |
Soil | Filter media required | Amendment preferable when possible |
Underdrain | Common | Uncommon |
Maintenance | Medium to high | Low |
Stormwater benefit | High | Moderate |
Biodiversity benefit | Increased with native planting | Typically lower |
Planning considerations[edit]
Design[edit]
Element | Design Objective | Criteria |
---|---|---|
Drainage Area | Sustaining vegetation, volumetric turnover | 5 Ha (≥10 Ha preferred) |
Treatment Volume | Provision of appropriate level of protection (Table 3.2) | See Table 3.2 |
Active Storage | Detention | Suspended solids settling 24 hrs (12 hrs if in conflict with min. orifice size) |
Forebay | Pre-treatment |
|
Length-to-Width Ratio | Maximize flow path and minimize short-circuiting potential |
|
Permanent Pool Depth | Vegetation requirements, rapid settling | The average permanent pool depth should range from 150 mm to 300 mm |
Active Storage Depth | Storage/flow control, sustaining vegetation | Maximum 1.0 m for storms < 10 year event |
Side Slopes | Safety |
|
Inlet | Avoid clogging/freezing |
|
Outlet | Avoid clogging/freezing |
|
Maintenance Access | Access for backhoes or dredging equipment |
|
Buffer | Safety | Minimum 7.5 m above maximum water quality/erosion control water level |
Performance[edit]
STEP (under previous name SWAMP) conducted their own research into the performance of stormwater wetlands, the project page and report can be viewed here.
Gallery[edit]
Emergent wetland vegetation supported by stormwater runoff at Kino Environmental Restoration Project. Photo by Matthew Grabau, US Fish and Wildlife Service
Azalea Park, Charlottesville VA - "This side of the park, formerly located along a runoff channel that led into Moore's Creek, has been converted into a wetland which supports a surprising amount of insect and amphibian life." -Credit and Photo: Scott Clark (certhia on Flickr).