Changes

[[File:PP IWS.gif|thumb|Conceptual diagram illustrating an adjustable storage underdrain configuration beneath permeable interlocking pavers]]

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

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==Overview==

==Overview==

* Pervious concrete  

* Pervious concrete  

* Pervious asphalt

* Pervious asphalt

{{textbox|Permeable paving is ideal for:

{{textbox|Permeable paving is ideal for:

*Sites with limited space for other surface stormwater BMPs

*Sites with limited space for other surface stormwater BMPs

'''Additional components may include:'''

'''Additional components may include:'''

*an underdrain system

*an [[underdrain]] system

==Planning considerations==

==Planning considerations==

===Geometry and Site Layout===

===Geometry and Site Layout===

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 themselves are impervious asphalt. In general, the impervious area should not exceed 1.2 times the area of the permeable paving which receives the runoff. A hybrid permeable paving/[[infiltration chamber]] design can feature connection of a roof downspout directly to the stone reservoir of the permeable paving system, which is sized to store runoff from both the pavement surface and the roof drainage area.  

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 themselves are impervious asphalt. In general, the impervious area should not exceed the area of the permeable paving which receives the runoff.  

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

===Pretreatment===

===Pretreatment===

===Risk of Groundwater Contamination===

===Risk of Groundwater Contamination===

*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

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

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

===Heavy Vehicle Traffic===

===Heavy Vehicle Traffic===

Permeable paving 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.

Permeable paving 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.

==Design==

==Design==

===Modeling permeable paving in the Treatment Train Tool===

===Finish course===

'''[[Permeable paving: TTT]]'''

 

{{:Permeable paving: Specifications}}

 

===Foundation aggregates===

[[File:Geogitter-4.jpg|thumb|Geogrids like these are sometimes incorporated into the layers of permeable pavement foundation aggregates to provide additional stability]]

Most [[OPSS aggregates]] are not recommended for use in permeable paving systems. The exception being type 'o' with a default void ratio of 0.3.

 

===Sizing stone reservoirs===

===Sizing stone reservoirs===

The stone reservoir must meet both runoff storage and structural support requirements.

The stone reservoir must meet both runoff storage and structural support requirements.

The bottom of the reservoir should be level so that water infiltrates evenly. If the system is not designed for infiltration, the bottom should slope at 1 - 5% toward the underdrain.  

The bottom of the reservoir should be level so that water infiltrates evenly.<br>

If the system is not designed for infiltration, the bottom should slope at 1 - 5% toward the underdrain.  

 

'''[[Permeable paving: Sizing and modeling]]'''

'''[[Permeable paving: TTT]]'''

===Materials===

==Gallery==

{{:Permeable paving: Gallery}}

===Aggregates===

{{:choker layer}}

{{:Geotextiles}}

===Landscaping===

==Landscaping and grading==

Landscaped areas should drain away from permeable paving to prevent sediments from running onto the surface. Urban [[trees]] benefit from being surrounded by permeable pavement rather than impervious cover, because their roots receive more air and water, and pavers used around the base of a tree can be removed as the tree grows.

Landscaped areas ''must'' be [[grading|graded]] drain away from permeable paving to prevent sediment from running onto the surface. <br>

Urban [[trees]] benefit from being surrounded by permeable pavement rather than impervious cover, because their roots receive more air and water. Block pavers around the base of a tree can be removed as the tree grows.

==Performance==

==Performance==

Permeable pavers can be classified into two categories according to the infiltration rate of the underlying subsoil:

Permeable pavers can be classified into two categories according to the infiltration rate of the underlying subsoil:

*Full Infiltration: Full infiltration designs are more effective, because little if any of the pollutants generated on the impermeable surfaces leave the site as surface runoff

*Full Infiltration: Full infiltration designs are more effective, because little if any of the pollutants generated on the impermeable surfaces leave the site as surface runoff

Studies in North Carolina have shown the average curve number of permeable pavements to range from a low of 45 to a high of 89. <ref>Bean, E.Z., Hunt, W, F., Bidelspach, D.A. 2007a. Evaluation of Four Permeable Pavement Sites in Eastern North Carolina for Runoff Reduction and Water Quality Impacts. Journal of Irrigation and Drainage Engineering. Vol. 133. No. 6. pp. 583-592.</ref><br>

Studies in North Carolina have shown the average curve number of permeable pavements to range from a low of 45 to a high of 89. <ref>Bean, E.Z., Hunt, W, F., Bidelspach, D.A. 2007a. Evaluation of Four Permeable Pavement Sites in Eastern North Carolina for Runoff Reduction and Water Quality Impacts. Journal of Irrigation and Drainage Engineering. Vol. 133. No. 6. pp. 583-592.</ref><br>

Partial infiltration designs with underdrains generate more runoff, and as a result, are often used in studies investigating the water quality impact of permeable pavements on surface waters. These studies show load reductions above 50% for total suspended solids, most metals and hydrocarbons <ref>Legret, M and V. Colandani. 1999. Effects of a porous pavement structure with a reservoir structure on runoff water: water quality and fate of metals. Water Science and Technology. 39(2): 111-117</ref> <ref>Pratt, C.J., Mantle, J.D.G., Schofield, P.A. 1995. UK research into the performance of permeable pavement reservoir structures in controlling stormwater discharge quantity and quality. Water Science Technology. Vol. 32. No. 1. pp. 63-69.</ref> <br>

Partial infiltration designs with underdrains generate more runoff, and as a result, are often used in studies investigating the water quality impact of permeable pavements on surface waters. These studies show load reductions above 50% for total suspended solids, most metals and hydrocarbons <ref>Legret, M and V. Colandani. 1999. Effects of a porous pavement structure with a reservoir structure on runoff water: water quality and fate of metals. Water Science and Technology. 39(2): 111-117</ref> <ref>Pratt, C.J., Mantle, J.D.G., Schofield, P.A. 1995. UK research into the performance of permeable pavement reservoir structures in controlling stormwater discharge quantity and quality. Water Science Technology. Vol. 32. No. 1. pp. 63-69.</ref> <br>

As with all stormwater infiltration practices, risk of groundwater contamination from infiltration of runoff laden with road de-icing salt constituents (typically sodium and chloride) is a significant concern. Chloride ions are extremely mobile in the soil and are readily transported by percolating water to aquifers.

As with all stormwater infiltration practices, risk of groundwater contamination from infiltration of runoff laden with road de-icing [[salt]] constituents (typically sodium and chloride) is a significant concern. Chloride ions are extremely mobile in the soil and are readily transported by percolating water to aquifers.

==Construction Considerations==

==Construction Considerations==

==Proprietary Links==

==Proprietary Links==

{{:Disclaimer}}

{{:Disclaimer}}

===Pre-cast===

===Pre-cast with spaces===

*[https://unilock.com/products/driveways/eco-optiloc/?region=1 Eco-Optioc, Unilock]

*[https://unilock.com/products/driveways/eco-optiloc/?region=1 Eco-Optioc, Unilock]

*[https://oakspavers.com/products/enviro-pavers Enviro Pavers, Oaks]

*[https://oakspavers.com/products/enviro-pavers Enviro Pavers, Oaks]

*[http://nilex.com/products/pavedrain Pavedrain, distributed by Nilex]

*[http://nilex.com/products/pavedrain Pavedrain, distributed by Nilex]

*[http://santerrastonecraft.com/landscape/paving-stones/terra-flo Terra flo, Santerra]

*[http://santerrastonecraft.com/landscape/paving-stones/terra-flo Terra flo, Santerra]

*[http://www.storm-crete.com/ Stormcrete pervious pavers]

*[http://www.storm-crete.com/ Stormcrete pervious pavers]

===Poured in place===

 

===Cast in place===

*[http://www.lafarge-na.com/wps/portal/na/en/HydromediaDetailWCM_GLOBAL_CONTEXT=/wps/wcm/connectlib_na/Site_na/AllProductDataSheet_Concrete/ProductDatasheet_Concrete_1321037540751/Product_EN Hydromedia]

*[http://www.lafarge-na.com/wps/portal/na/en/HydromediaDetailWCM_GLOBAL_CONTEXT=/wps/wcm/connectlib_na/Site_na/AllProductDataSheet_Concrete/ProductDatasheet_Concrete_1321037540751/Product_EN Hydromedia]

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