Changes

{{TOClimit|2}}

{{TOClimit|2}}

==Overview==

==Overview==

Permeable pavements are an alternative to conventional impervious pavement that allows stormwater to drain through the surface and into a stone reservoir, where it infiltrates into the underlying native soil or is temporarily detained.  Depending on the native soil properties and physical constraints, the system may be designed with no underdrain for full infiltration, with an underdrain for partial infiltration, or with an impermeable liner and underdrain for a non-infiltrating, or detention and filtration only practice.  

Permeable pavements are an alternative to conventional impervious pavement that allows stormwater to drain through the surface and into a stone reservoir, where it infiltrates into the underlying native soil or is temporarily detained.  Depending on the native soil properties and physical constraints, the system may be designed with no underdrain for full infiltration, with an underdrain for partial infiltration, or with an impermeable liner and underdrain for a non-infiltrating, or detention and filtration only practice.  

* geo-grids for sites with heavy vehicle loading

* geo-grids for sites with heavy vehicle loading

* monitoring wells and clean-outs

* monitoring wells and clean-outs

==Planning considerations==

==Planning considerations==

===Space===

===Space===

[[File:IMAX permeable pavement.JPG|thumb|Permeable pavement in the IMAX parking lot, Mississauga ON]]

[[File:IMAX permeable pavement.JPG|thumb|500px|Permeable pavement in the IMAX parking lot, Mississauga ON]]

Permeable pavements can be used for the entire parking lot, driveway or road surface, or be designed to to receive runoff from adjacent impervious surfaces. For example, the parking spaces of a parking lot or road can be permeable pavements while the drive lanes are conventional asphalt. The impervious area draining on to the permeable pavement should not exceed the area of the permeable pavement itself. Relatively clean drainage areas such as roofs may be up to 4 times the size of the pavement but should include filtration pretreatment to remove coarse debris prior to being conveyed directly to the storage reservoir.   

Permeable pavements can be used for the entire parking lot, driveway or road surface, or be designed to to receive runoff from adjacent impervious surfaces. For example, the parking spaces of a parking lot or road can be permeable pavements while the drive lanes are conventional asphalt. The impervious area draining on to the permeable pavement should not exceed the area of the permeable pavement itself. Relatively clean drainage areas such as roofs may be up to 4 times the size of the pavement but should include filtration pretreatment to remove coarse debris prior to being conveyed directly to the storage reservoir.   

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.

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.

{{:Permeable paving: Specifications}}

{{:Permeable pavements: Specifications}}

===Foundation Aggregates===

===Foundation Aggregates===

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

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

'''[[Permeable paving: Sizing]]'''

'''[[Permeable pavements: Sizing]]'''

===Geotextile===

===Geotextile===

[[Geotextiles]] are non-woven needle punched, or woven monofilament geotextile fabric that may be placed between the storage reservoir and native soil to maintain separation. Geotextiles are commonly used on low strength soils (CBR <4).  Where expansive clays are present, a non-infiltrating design may be necessary.  If used, geotextile socks around perforated pipes should conform to ASTM D6707 with minimum water flow rate conforming to ASTM D4491 (12,263 L/min/m2 at 5 cm head).

[[Geotextiles]] are non-woven needle punched, or woven monofilament geotextile fabric that may be placed between the storage reservoir and native soil to maintain separation. Geotextiles are commonly used on low strength soils (CBR <4).  Where expansive clays are present, a non-infiltrating design may be necessary.  If used, geotextile socks around perforated pipes should conform to ASTM D6707 with minimum water flow rate conforming to ASTM D4491 (12,263 L/min/m2 at 5 cm head).

File:Geogitter-4.jpg|Geogrids like these are sometimes incorporated into the layers of permeable pavement foundation aggregates to provide additional stability and conserve aggregate material.

File:Geogitter-4.jpg|Geogrids like these are sometimes incorporated into the layers of permeable pavement foundation aggregates to provide additional stability and conserve aggregate material.

</gallery>

</gallery>

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

===Modelling permeable pavements in the Treatment Train Tool===

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

'''[[Permeable pavements: TTT]]'''

==Construction Considerations==

==Construction Considerations==

==Inspection and Maintenance==

==Inspection and Maintenance==

Permeable pavements require regular inspection and maintenance to ensure proper functioning. The limiting factor for permeable pavements is clogging of the surface course or joint filler between pavers. As these start to fill, the trapped sediment becomes finer and finer until they eventually become clogged. Ideally, signs should be posted on the site identifying permeable pavement. This can also serve as a public awareness and education opportunity. See: [[Permeable paving: Maintenance|Permeable pavement: Maintenance]]

Permeable pavements require regular inspection and maintenance to ensure proper functioning. The limiting factor for permeable pavements is clogging of the surface course or joint filler between pavers. As these start to fill, the trapped sediment becomes finer and finer until they eventually become clogged. Ideally, signs should be posted on the site identifying permeable pavement. This can also serve as a public awareness and education opportunity. See: [[Permeable pavements: Maintenance]]

==Life Cycle Costs==

==Life Cycle Costs==

===Water Quality===

===Water Quality===

Like other stormwater practices, the water quality performance of permeable pavements is closely tied to the reduction of runoff volumes through infiltration, However, permeable pavements are also very effective stormwater runoff filters.  Most sediments and associated contaminants are trapped within the surface pores or gravel filled joints between the pavers.  A five year study of three permeable pavement surfaces in Vaughan showed total suspended solids (TSS) concentration reductions between 88 and 89% [https://sustainabletechnologies.ca/app/uploads/2016/02/KPP-Ext_FinalReport_Dec2015.pdf/ (Van Seters and Drake, 2015)].  Other STEP studies in the Greater Toronto Area have displayed similar results, with only 7% of 181 permeable pavement effluent samples having TSS concentrations above 30 mg/L (median = 7 mg/L)[https://sustainabletechnologies.ca/app/uploads/2015/06/SynthesisWaterQuality_Statistics_May2015.pdf/ TRCA, 2015].

Like other stormwater practices, the water quality performance of permeable pavements is closely tied to the reduction of runoff volumes through infiltration, However, permeable pavements are also very effective stormwater runoff filters.  Most sediments and associated contaminants are trapped within the surface pores or gravel filled joints between the pavers.  A five year study of three permeable pavement surfaces in Vaughan showed total suspended solids (TSS) concentration reductions between 88 and 89% [https://sustainabletechnologies.ca/app/uploads/2016/02/KPP-Ext_FinalReport_Dec2015.pdf/ (Van Seters and Drake, 2015)].  Other STEP studies in the Greater Toronto Area have displayed similar results, with only 7% of 181 permeable pavement effluent samples having TSS concentrations above 30 mg/L (median = 7 mg/L)[https://sustainabletechnologies.ca/app/uploads/2015/06/SynthesisWaterQuality_Statistics_May2015.pdf/ TRCA, 2015].

*[https://permacon.ca/en/ Permacon]

*[https://permacon.ca/en/ Permacon]

==Gallery==

==Gallery==

{{:Permeable paving: Gallery}}

{{:Permeable pavements: Gallery}}

----

----