Difference between revisions of "Swales"

From LID SWM Planning and Design Guide
Jump to navigation Jump to search
Line 4: Line 4:
===Overview===
===Overview===
<p>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:<br>
<p>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:<br>
<strong>Bioswales</strong> are sometimes referred to as 'dry swales', 'vegetated swales', 'water quality swales' or 'inline bioretention'. This type of structure is similar to a [[Bioretention cells|bioretention cell]] but with a linear shape (typically >2:1 )<br>
<strong>Bioswales</strong> are sometimes referred to as 'dry swales', 'vegetated swales', 'water quality swales' or 'inline bioretention'. This type of structure is similar to a [[Bioretention cells|bioretention cell]] but with a long linear shape (surface area typically >2:1 )<br>
<strong>Enhanced Grass Swales</strong> 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.   
<strong>Enhanced Grass Swales</strong> 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.   
</p>  
</p>  
Line 27: Line 27:
<p><strong>The fundamental components of a swale are:</strong>
<p><strong>The fundamental components of a swale are:</strong>
<ul>
<ul>
<li> graded channel</li>
<li> Graded channel</li>
<li> planting </li>
<li> Planting </li>
</ul>
</ul>
<strong>Additional components may include:</strong>
<strong>Additional components may include:</strong>
<ul>
<ul>
<li>Biomedia - an engineered soil mix</li>
<li>Biomedia - an engineered soil mix</li>
<li>Planting </li>
<li>Underdrain with clean out and inspection ports</li>
<li>Underdrain with clean out and inspection ports</li>
<li>Impermeable membrane to prevent infiltration to soils below</li>
<li>Impermeable membrane to prevent infiltration to soils below</li>

Revision as of 19:30, 27 June 2017

This article is about installations designed to capture and convey surface runoff along a vegetated channel.

Overview[edit]

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', 'water quality swales' or 'inline bioretention'. This type of structure is similar to a bioretention cell but with a long linear shape (surface area typically >2:1 )
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.

Swales are an ideal technology for:

  • Sites with long linear landscaped areas, such as parking lots
  • Connecting with one or more other types of LID
Types of Swales
PropertyBioswaleEnhanced Grass Swale
Surface waterMinimal
Any surface flow can be slowed with check dams		Ponding is encouraged with check dams
Engineered soilBiomedia requiredAmendment preferable when possible
UnderdrainCommonUncommon
MaintenanceMedium to highLow
Stormwater benefitHighMedium
Biodiversity benefitIncreased with native plantingLower

The fundamental components of a swale are:

  • Graded channel
  • Planting

Additional components may include:

  • Biomedia - an engineered soil mix
  • Underdrain with clean out and inspection ports
  • Impermeable membrane to prevent infiltration to soils below
  • Check dams

<panelSuccess>

  • Bioswale?

</panelSuccess>

Planning Considerations[edit]

Planning Content

<panelSuccess>

  • Placeholder.

</panelSuccess>

Design[edit]

Design Content

<panelSuccess>

  • Bioretention cell capturing and treating runoff from adjacent parking lot at the Kortright Centre, Vaughan.

</panelSuccess>

Performance[edit]

Performance Content

<panelSuccess>

  • Placeholder

</panelSuccess>

Incentives and Credits[edit]

In Ontario

City of Mississauga
The City of Mississauga has a stormwater management credit program which includes RWH as one of their recommended site strategies[1].

LEED BD + C v. 4

SITES v.2

See Also[edit]

External Links[edit]

  SEND US YOUR QUESTIONS & FEEDBACK ABOUT THIS PAGE

The portion of water precipitated onto a catchment area, which then flows as surface discharge from the catchment area past a specified point.

Water from rain, snow melt, or irrigation that flows over the land surface.

A shallow constructed channel, often grass-lined, which is used as an alternative to curb and channel, or as a pretreatment to other measures. Swales are generally characterized by a broad top width to depth ratio and gentle grades.

A shallow constructed channel, often grass-lined, which is used as an alternative to curb and channel, or as a pretreatment to other measures. Swales are generally characterized by a broad top width to depth ratio and gentle grades.

A stormwater management strategy that seeks to mitigate the impacts of increased urban runoff and stormwater pollution by managing it as close to its source as possible. It comprises a set of site design approaches and small scale stormwater management practices that promote the use of natural systems for infiltration and evapotranspiration, and rainwater harvesting.

Linear bioretention cell designed to convey, treat and attenuate stormwater runoff. The engineered filter media soil mixture and vegetation slows the runoff water to allow sedimentation, filtration through the root zone, evapotranspiration, and infiltration into the underlying native soil.

Linear bioretention cell designed to convey, treat and attenuate stormwater runoff. The engineered filter media soil mixture and vegetation slows the runoff water to allow sedimentation, filtration through the root zone, evapotranspiration, and infiltration into the underlying native soil.

A shallow constructed channel, often grass-lined, which is used as an alternative to curb and channel, or as a pretreatment to other measures. Swales are generally characterized by a broad top width to depth ratio and gentle grades.

A shallow constructed channel, often grass-lined, which is used as an alternative to curb and channel, or as a pretreatment to other measures. Swales are generally characterized by a broad top width to depth ratio and gentle grades.

Refers to a system that accepts all of the flow from a drainage area and conveys larger event flows through an overflow outlet.

A shallow excavated surface depression containing prepared filter media, mulch, and planted with selected vegetation.

Emphasis on improving the value of particular aspects of water and related land resources.

A shallow constructed channel, often grass-lined, which is used as an alternative to curb and channel, or as a pretreatment to other measures. Swales are generally characterized by a broad top width to depth ratio and gentle grades.

Vegetated, open channels designed to convey, treat and attenuate runoff. Design variations range from simple grass channels, which are designed primarily for conveyance to more complex treatment and volume reduction designs like enhanced grass swales, and dry swales or bioswales.

Structures constructed of a non-erosive material, such as suitably sized aggregate, wood, gabions, riprap, or concrete; used to slow runoff water. Can be employed in practices such as bioswales and enhanced grass swales.

Low Impact Development. A stormwater management strategy that seeks to mitigate the impacts of increased urban runoff and stormwater pollution by managing it as close to its source as possible. It comprises a set of site design approaches and small scale stormwater management practices that promote the use of natural systems for infiltration and evapotranspiration, and rainwater harvesting.

Linear bioretention cell designed to convey, treat and attenuate stormwater runoff. The engineered filter media soil mixture and vegetation slows the runoff water to allow sedimentation, filtration through the root zone, evapotranspiration, and infiltration into the underlying native soil.

A shallow constructed channel, often grass-lined, which is used as an alternative to curb and channel, or as a pretreatment to other measures. Swales are generally characterized by a broad top width to depth ratio and gentle grades.

A perforated pipe used to assist the draining of soils.

Structures constructed of a non-erosive material, such as suitably sized aggregate, wood, gabions, riprap, or concrete; used to slow runoff water. Can be employed in practices such as bioswales and enhanced grass swales.

A shallow excavated surface depression containing prepared filter media, mulch, and planted with selected vegetation.

Rainwater harvesting.

Retrieved from "https://wikidev.sustainabletechnologies.ca/index.php?title=Swales&oldid=1285"