Changes

[[File:PP IWS.gif|frame|Conceptual diagram illustrating an adjustable storage underdrain configuration beneath permeable interlocking pavers]]{{TOClimit|2}}

[[File:PP IWS.gif|frame|Conceptual diagram illustrating an adjustable storage underdrain configuration beneath permeable interlocking pavers]]{{TOClimit|2}}

==Overview==

==Overview==

Permeable paving allows stormwater to drain through the surface and into a stone reservoir. There it is infiltrated into the underlying native soil or temporarily detained.  

Permeable paving allows stormwater to drain through the surface and into a stone reservoir, where it infiltrates into the underlying native soil or is temporarily detained.  

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PerviousConcreteWalkwayPlaza.png|Pervious Concrete Walkway Plaza

PerviousConcreteWalkwayPlaza.png|Pervious Concrete Walkway Plaza

* Permeable interlocking concrete pavers  

* Permeable interlocking concrete pavers  

* Plastic or concrete grid systems  

* Plastic or concrete grid systems  

* Pervious concrete; and

* Pervious concrete  

* Pervious asphalt.

* Pervious asphalt

{{textbox|Permeable paving is ideal for:

{{textbox|Permeable paving is ideal for:

'''The fundamental components of a permeable paving system are:'''

'''The fundamental components of a permeable paving system are:'''

*interlocking blocks with infiltration spaces between, '''or'''

*interlocking blocks with infiltration spaces between

*Precast pervious slabs or pavers, '''or'''

*Precast pervious slabs or pavers

*a cast in place surface without fines, so that the finish is pervious to water

*a cast in place surface without fines, so that the finish is pervious to water

*a bedding course to stabilize the surface

*a bedding course to stabilize the surface

*underground storage layer of aggregate.

*underground storage layer of aggregate

'''Additional components may include:'''

'''Additional components may include:'''

==Planning considerations==

==Planning considerations==

<h3>Geometry and Site Layout</h3>

<h3>Geometry and Site Layout</h3>

Permeable paving can be used for entire parking lot areas or driveways or can be designed to receive runoff from adjacent impervious surfaces

Permeable paving can be used for entire parking lot areas or driveways and can be designed to receive runoff from adjacent impervious surfaces. For example, the parking spaces in a parking lot may be permeable pavers while the drive lanes themsevles are impervious asphalt.  

For example, the parking spaces of a parking lot may be permeable pavers while the drive lanes are impervious asphalt.  

 

In general, the impervious area should not exceed 1.2 times the area of the permeable pavement which receives the runoff.  

In general, the impervious area should not exceed 1.2 times the area of the permeable pavement which receives the runoff.  

A hybrid permeable pavement/soakaway design can feature connection of a roof downspout directly to the stone reservoir of the permeable pavement system, which is sized to store runoff from both the pavement surface and the roof drainage area.  

A hybrid permeable pavement/soakaway design can feature connection of a roof downspout directly to the stone reservoir of the permeable pavement system, which is sized to store runoff from both the pavement surface and the roof drainage area.  

<h3>Risk of Groundwater Contamination</h3>

<h3>Risk of Groundwater Contamination</h3>

*Stormwater infiltration practices should not receive runoff from high traffic areas where large amounts of de-icing salts are applied (e.g., busy highways), nor from pollution hot spots (e.g., source areas where land uses or activities have the potential to generate highly contaminated runoff such as vehicle fuelling, servicing or demolition areas, outdoor storage or handling areas for hazardous materials and some heavy industry sites);

*Stormwater infiltration practices should not receive runoff from high traffic areas where large amounts of de-icing salts are applied (e.g., busy highways), nor from pollution hot spots (e.g., source areas where land uses or activities have the potential to generate highly contaminated runoff such as vehicle fuelling, servicing or demolition areas, outdoor storage or handling areas for hazardous materials and some heavy industry sites)

*Prioritize infiltration of runoff from source areas that are comparatively less contaminated such as  roofs, low traffic roads and parking areas; and,

*Prioritize infiltration of runoff from source areas that are comparatively less contaminated such as  roofs, low traffic roads and parking areas

*Apply sedimentation pretreatment practices (e.g., oil and grit separators) before infiltration of road or parking area runoff.

*Apply sedimentation pretreatment practices (e.g., oil and grit separators) before infiltration of road or parking area runoff

<h3>Heavy Vehicle Traffic</h3>

<h3>Heavy Vehicle Traffic</h3>

Permeable pavement is not typically used in locations subject to heavy loads. Some permeable pavers are designed for heavy loads and have been used in commercial port loading and storage areas.

Permeable pavement is not typically used in locations subject to heavy loads. However, some permeable pavers are designed for heavy loads and have been used in commercial port loading and storage areas.

<h3>Setbacks from Buildings</h3>

<h3>Setbacks from Buildings</h3>

<h3>On Private Property</h3>

<h3>On Private Property</h3>

If permeable pavement systems are installed on private lots, property owners  or managers will need to be educated on their routine maintenance needs, understand the long-term maintenance plan, and may be subject to a legally binding maintenance agreement. An incentive program such as a storm sewer user fee based on the area of impervious cover on a property that is directly connected to a storm sewer could be used to encourage property owners or managers to maintain existing practices.

If permeable pavement systems are installed on private lots, property owners  or managers will need education on their routine maintenance needs, understanding the long-term maintenance plan. They may also be subject to a legally binding maintenance agreement. An incentive program, such as a storm sewer user fee based on the area of impervious cover on a property that is directly connected to a storm sewer, could be used to encourage property owners or managers to maintain existing practices.

==Design==

==Design==

===Materials===

===Materials===

The manufacturer should be consulted for the design specifications of their product. In pervious concrete and porous asphalt systems, the concrete or asphalt mix specifications and construction procedure are key to proper functioning. These systems require well trained and experienced contractors for installation.<br>

Consult the manufacturer for the design specifications of their product. In pervious concrete and porous asphalt systems, the concrete or asphalt mix specifications and construction procedures are key to proper functioning. These systems require well-trained and experienced contractors for installation.<br>

'''[[Permeable paving: Specifications|Specifications]]'''

'''[[Permeable paving: Specifications|Specifications]]'''