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| This article is about installations designed to capture and convey surface runoff along a vegetated channel, whilst also promoting infiltration. <br> | | This article is about installations designed to capture and convey surface runoff along a vegetated channel, whilst also promoting infiltration. <br> |
| For underground conveyance which promotes infiltration, see [[Exfiltration trenches]]. | | For underground conveyance which promotes infiltration, see [[Exfiltration trenches]]. |
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| ==Overview== | | ==Overview== |
| [[File:20161024 100338 550x550.jpg|thumb|Bioswale, County Court Boulevard, Brampton]] | | [[File:20161024 100338 550x550.jpg|thumb|Bioswale, County Court Boulevard, Brampton]] |
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| Swales are linear landscape features consisting of a drainage channel with gently sloping sides. Underground they may be filled with engineered soil and/or contain a water storage layer of coarse gravel material. Two variations on a basic swale are recommended as low impact development strategies, although using a combination design of both may increase the benefits: | | Swales are linear landscape features consisting of a drainage channel with gently sloping sides. Underground they may be filled with engineered soil and/or contain a water storage layer of coarse gravel material. Two variations on a basic swale are recommended as low impact development strategies, although using a combination design of both may increase the benefits: |
| *[[Bioswales]] are sometimes referred to as 'dry swales', 'vegetated swales', or 'water quality swales'. This type of structure is similar to a [[Bioretention cells|bioretention cell]] but with a long linear shape (surface area typically >2:1 length:width ) | | *[[Bioswales]] are sometimes referred to as 'dry swales', 'vegetated swales', or 'water quality swales'. This type of structure is similar to a [[Bioretention cells|bioretention cell]] but with a long linear shape (surface area typically >2:1 length:width ) |
| *[[Enhanced grass swales]] are a lower maintenance alternative, but generally have lower stormwater management potential. The enhancement over a basic grass swale is in the addition of check dams to slow surface water flow and create small temporary pools of water which can infiltrate the underlying soil. | | *[[Enhanced grass swales]] are a lower maintenance alternative, but generally have lower stormwater management potential. The enhancement over a basic grass swale is in the addition of check dams to slow surface water flow and create small temporary pools of water which can infiltrate the underlying soil. |
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| {{TextBox|1=Swales are an ideal technology for: | | {{TextBox|1=Swales are an ideal technology for: |
| *Sites with long linear landscaped areas, such as parking lots | | *Sites with long linear landscaped areas, such as parking lots |
| *Connecting with one or more other types of LID}} | | *Connecting with one or more other types of LID}} |
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| {| class="wikitable" | | {| class="wikitable" |
| |+ Types of Swale | | |+ Types of Swale |
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| !Underdrain | | !Underdrain |
| |Common||Uncommon | | |Common||Uncommon |
| + | !Maintenance |
| + | |Medium to high||Low |
| + | !Stormwater benefit |
| + | |High||Moderate |
| + | !Biodiversity benefit |
| + | |Increased with native planting||Typically lower |
| |} | | |} |
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− | <table class="table-responsive" table class="table table-striped">
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− | <caption><strong>Types of Swales</strong></caption>
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− | <th>Property</th>
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− | <th>Bioswale</th>
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− | <th>Enhanced Grass Swale</th>
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− | </tr>
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− | <td>Surface water</td>
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− | <td>Minimal
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− | <br>Any surface flow can be slowed with check dams</td>
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− | <td>Ponding is encouraged with check dams</td>
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− | </tr>
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− | <tr>
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− | <td>Engineered soil</td>
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− | <td>Filter media required</td>
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− | <td>Amendment preferable when possible</td>
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− | </tr>
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− | <tr>
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− | <td>Underdrain</td>
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− | <td>Common</td>
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− | <td>Uncommon</td>
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− | </tr>
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− | <tr>
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− | <td>Maintenance</td>
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− | <td>Medium to high</td>
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− | <td>Low</td>
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− | </tr>
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− | <tr>
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− | <td>Stormwater benefit</td>
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− | <td>High</td>
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− | <td>Medium</td>
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− | </tr>
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− | <tr>
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− | <td>Biodiversity benefit</td>
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− | <td>Increased with native planting</td>
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− | <td>Lower</td>
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− | </tr>
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− | </table>
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− | </div>
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− | <panelWarning>
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− | <gallery mode="packed" widths=300px heights=300px>
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− | 20161024 100338 550x550.jpg| Bioswale, County Court Boulevard, Brampton
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− | </gallery>
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− | </panelWarning>
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− | </div>
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| ==Planning Considerations== | | ==Planning Considerations== |
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