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]]

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==Overview==

==Overview==

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.  

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.  

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>Pretreatment</h3>

===Pretreatment===

In most designs, the surface acts as pretreatment to the stone reservoir below. Periodic vacuum sweeping and preventative measures like not storing snow or other materials on the pavement are critical to prevent clogging. Another pretreatment element is a pea gravel choking layer above the coarse gravel storage reservoir.

In most designs, the surface acts as pretreatment to the stone reservoir below. Periodic vacuum sweeping and preventative measures like not storing snow or other materials on the pavement are critical to prevent clogging. Another pretreatment element is a pea gravel choking layer above the coarse gravel storage reservoir.

<h3>Landscaping</h3>

===Landscaping===

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

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

<h3>Risk of Groundwater Contamination</h3>

===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  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>

===Heavy Vehicle Traffic===

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.

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>

===Setbacks from Buildings===

Permeable pavement should be located downslope from building foundations. If the pavement does not receive runoff from other surfaces, no setback is required from building foundations. Otherwise, a minimum setback of 4 m down-gradient from building foundations is recommended.

Permeable pavement should be located downslope from building foundations. If the pavement does not receive runoff from other surfaces, no setback is required from building foundations. Otherwise, a minimum setback of 4 m down-gradient from building foundations is recommended.

<h3>On Private Property</h3>

===On Private Property===

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.

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.

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

{{:Gravel}}

{{:Reservoir aggregate}}

====Geotextile====

====Geotextile====

Initial construction costs for permeable pavements are typically higher than conventional asphalt pavement surfaces, largely due to thicker aggregate base needed for stormwater storage. However, the cost difference is reduced or eliminated when total life-cycle costs, or the total cost to construct and maintain the pavement over its lifespan, are considered. Other potential savings and benefits include reduced need for storm sewer pipes and other stormwater practices, less developable land consumed for stormwater treatment, and ancillary benefits (improved aesthetics and reduced urban heat island effect). These systems are especially cost effective in existing urban development where parking lot expansion is needed, but there is not sufficient space for other types of BMPs. They combine parking, stormwater infiltration, retention, and detention into one facility.

Initial construction costs for permeable pavements are typically higher than conventional asphalt pavement surfaces, largely due to thicker aggregate base needed for stormwater storage. However, the cost difference is reduced or eliminated when total life-cycle costs, or the total cost to construct and maintain the pavement over its lifespan, are considered. Other potential savings and benefits include reduced need for storm sewer pipes and other stormwater practices, less developable land consumed for stormwater treatment, and ancillary benefits (improved aesthetics and reduced urban heat island effect). These systems are especially cost effective in existing urban development where parking lot expansion is needed, but there is not sufficient space for other types of BMPs. They combine parking, stormwater infiltration, retention, and detention into one facility.

<h2>Incentives and Credits <ref>http://www7.mississauga.ca/Departments/Marketing/stormwater/stormwater-charge/img/stormwater-credits-manual-0.1.pdf</ref></h2>

===Incentives and Credits===

<h3>Objective</h3>

<ref>http://www7.mississauga.ca/Departments/Marketing/stormwater/stormwater-charge/img/stormwater-credits-manual-0.1.pdf</ref>

===Objective===

The key objective of the Stormwater Credit Program is to recognize property owners who have

The key objective of the Stormwater Credit Program is to recognize property owners who have

implemented stormwater and/or [[Pollution prevention|pollution prevention]] best management practices (“BMPs”) to reduce

implemented stormwater and/or [[Pollution prevention|pollution prevention]] best management practices (“BMPs”) to reduce

leaving their property.

leaving their property.

<h3>Principles</h3>

===Principles===

The Stormwater Credit Program is designed according to the following guiding principles:

The Stormwater Credit Program is designed according to the following guiding principles:

* Available to every non-residential and multi-residential property (including those considered “mixed-use”) in Mississauga, unless otherwise exempt from stormwater charges or receiving a subsidy to offset stormwater charges.

* Available to every non-residential and multi-residential property (including those considered “mixed-use”) in Mississauga, unless otherwise exempt from stormwater charges or receiving a subsidy to offset stormwater charges.

* Property owners have the flexibility to pursue practices that suit the needs of and opportunities on their property.

* Property owners have the flexibility to pursue practices that suit the needs of and opportunities on their property.

<h3>Eligibility</h3>

===Eligibility===

All multi-residential and non-residential properties (including mixed-use properties) are eligible for the

All multi-residential and non-residential properties (including mixed-use properties) are eligible for the

credit program, except for any portion thereof which is receiving an exemption or subsidy reduction to

credit program, except for any portion thereof which is receiving an exemption or subsidy reduction to

the stormwater charge. Single residential properties are not eligible for the credit program.

the stormwater charge. Single residential properties are not eligible for the credit program.

<h3>Credit Schedule</h3>

===Credit Schedule===

Stormwater credits are available in each of four categories, which align with the overarching objectives

Stormwater credits are available in each of four categories, which align with the overarching objectives

of the City’s stormwater program as shown in the following table.

of the City’s stormwater program as shown in the following table.

==Proprietary Links==

==Proprietary Links==

{{:Disclaimer}}

{{:Disclaimer}}

<h3>Pre-cast</h3>

===Pre-cast===

*[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://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]

<h3>Poured in place</h3>

===Poured 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]