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Line 30: − + − + − + − − + − + − + − + − *Apply sedimentation pretreatment practices (e.g., oil and grit separators) before infiltration of road or parking area runoff − + + − + − + − + − '''[[Permeable paving: TTT]]'''+ + + − + − '''[[Permeable paving: Sizing and modeling]]'''+ + + + − + − 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]]''' − + − + − {{:Reservoir aggregate}}+ − ====Geotextile====+ − {{:Geotextiles}} − + − + + + + + + + + + Line 84:
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Line 104: − + − + − ===Incentives and Credits=== − <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 − implemented stormwater and/or [[Pollution prevention|pollution prevention]] best management practices (“BMPs”) to reduce − impacts to the City’s stormwater infrastructure by controlling the quantity and quality of stormwater − leaving their property. − − ===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. − * A clear linkage exists between the credit amounts provided and cost savings to the City’s stormwater program resulting from the implementation of BMPs. − * Property owners have the flexibility to pursue practices that suit the needs of and opportunities on their property. − − ===Eligibility=== − 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 − the stormwater charge. Single residential properties are not eligible for the credit program. − − ===Credit Schedule=== − 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. − − {| class="wikitable" − |style=" text-align: center"| [[Category]] || style=" text-align: center"|[[Evaluation Criteria]] ||colspan="2" style=" text-align: center" | [[Total Credit (50% Maximum)]] − |- − | Peak Flow Reduction || Percent reduction of the 100-year post development flow to pre-development conditions of the site || Up to 40% ||rowspan="4" style="background:; color:black"| To a total of no more than 50% − |- − | Water Quality Treatment || Consistent with Provincial criteria for enhanced treatment || Up to 10% − |- − | Runoff Volume Reduction || Percent capture of first 15 mm of rainfall during a single rainfall event || Up to 15% − |- − | Pollution Prevention || Develop and implement a pollution prevention plan || Up to 5% − |} − A maximum of 50% credit can be achieved by a property owner or operator. The 50% cap reflects the − maximum proportion of the City’s stormwater program in terms of cost that may be beneficially − impacted by on-site BMPs. The balance of the City’s program requires funding regardless of BMPs that − may be in place on private and public lands. − − ==References== − <references/> − + − *[http://hydropavers.ca/ Hydropavers pervious pavers] + + − + + + + + + + + +
→Poured in place
[[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 themsevles are impervious asphalt.
[[File:Perforated concrete block alt.jpg|thumb|Parking lot with perforated pavers in stalls only, Singapore]]
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.
In general, the impervious area should not exceed 1.2 times the area of the permeable pavement 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.
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.
===Pretreatment===
===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 to have a [[choking layer]] above the coarse gravel storage reservoir.
===Landscaping===
===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 paving to prevent sediments from running onto the surface. Urban [[trees]] will benefit from being surrounded by permeable paving 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.
===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.
===Heavy Vehicle Traffic===
===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.
[[File:PaveDrain.jpg|thumb|Many types of permeable surface are certified to ASSHTO-25, including PaveDrain PICP type paving, LSRCA headquarters, Newmarket, ON]]
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.
===Setbacks from Buildings===
===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 paving should be located downslope from building foundations. If the paving 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.
===On Private Property===
===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 paving 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==
===Modeling permeable paving in the Treatment Train Tool===
===Finish course===
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}}
===Sizing Stone Reservoirs===
===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.
*[[Choker layer]]
*[[Reservoir aggregate]]
===Materials===
===Geotextile===
[[Geotextiles]] are not always necessary and may be prone to [[clogging]]. Consider using courses of finer aggregates or sand instead.
====Stone Reservoir====
===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]]'''
===Landscaping===
===Modeling permeable paving in the Treatment Train Tool===
Landscaping plans should reflect the permeable pavement application. Landscaping areas should drain away from permeable pavement to prevent sediments from running onto the surface. Urban trees also benefit from being surrounded by permeable pavement rather than impervious cover, because their roots receive more air and water. Permeable pavers used around the base of a tree can be removed as the tree grows.
'''[[Permeable paving: TTT]]'''
==Gallery==
{{:Permeable paving: Gallery}}
==Landscaping and grading==
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==
{{:lit review}}
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==
Permeable pavements require regular inspection and maintenance to ensure proper functioning. The limiting factor for permeable pavers is clogging within the aggregate layers, filler, or underdrain. Ideally, signs should be posted on the site identifying permeable paver and porous pavement areas. This can also serve as a public awareness and education opportunity. See: [[Permeable paving: Maintenance]]
Permeable pavements require regular inspection and maintenance to ensure proper functioning. The limiting factor for permeable pavers is clogging within the aggregate layers, filler, or underdrain. Ideally, signs should be posted on the site identifying permeable paver and porous pavement areas. This can also serve as a public awareness and education opportunity. See: [[Permeable paving: Maintenance]]
==Life Cycle Costs==
==Life cycle costs==
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.
See also: [[Cost analysis resources]]
==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]
===Pre-cast pervious===
*[http://hydropavers.ca/ Hydropavers pervious pavers]
*[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]
*[https://www.purepave.com/ PurePave]
===Plastic grid===
*[https://www.ecorastergrid.com/ Ecoraster]
*[https://www.hahnplastics.com/ca/products/ground-reinforcement-and-surfaces/hanpave/4468/hanpave Hanpave]
*[https://www.hahnplastics.com/ca/products/ground-reinforcement-and-surfaces/heavy-duty-ground-grid/4533/heavy-duty-ground-grid HAHN heavy duty ground grid]
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