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![[Perforated Pipe]]
![[Perforated Pipe]]
|Perforated pipe systems should be located below shoulders of roadways, pervious boulevards or grass swales where they can be readily excavated for servicing. An adequate subsurface area outside of the four (4) metre setback from building foundations and suitable distance from other underground utilities must be available
|Perforated pipe systems should be located below shoulders of roadways, pervious boulevards or grass swales where they can be readily excavated for servicing. An adequate subsurface area outside of the four (4) metre setback from building foundations and suitable distance from other underground utilities must be available
|Systems cannot be located on natural slopes greater than 15%. The gravel bed should be designed with gentle slopes between 0.5 to 1%
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|Underlying native soil conditions do not constrain the use of perforated pipe systems but greatly influence their runoff reduction performance
|To protect groundwater from possible contamination, source areas where land uses or human activities have the potential to generate highly contaminated runoff should not be treated by perforated pipe systems.
|Facilities should be setback a minimum of four (4) metres from building foundations.
|Local utility design guidance should be consulted to define the horizontal and vertical offsets. Generally, requirements for underground utilities passing near the practice will be no different than for utilities in other pervious areas
|Systems typically receive foundation drain water and runoff from roofs, walkways, roads and parking lots from multiple lots. They are typically designed with an impervious drainage area to treatment facility area ratio of between 5:1 to 10:1
|Facilities receiving road or parking lot runoff should not be located within two (2) year time-of-travel wellhead protection areas.
|Designers should ensure that the bottom of the gravel bed is separated from the seasonally high water table or top of bedrock elevation by at least one (1) metre to prevent groundwater contamination
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!style="color: Brown "|Green Roofs
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|Green roofs are designed to capture precipitation falling directly onto the roof surface. They are not designed to receive runoff diverted from other source areas.
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|Load bearing capacity of the building structure and selected roof deck need to be sufficient to support the weight of the soil, vegetation and accumulated water or snow, and may also need to support pedestrians, concrete pavers, etc.
|Green roofs may be installed on roofs with slopes up to 10%
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!style="color: Brown "|Rainwater Harvesting
|Space limitations are rarely a concern with rainwater harvesting if considered during building design and site layout.
|Site topography influences the placement of storage tanks and the design of the rainwater conveyance and overflow systems.
|The needed head depends on intended use of the water. For residential landscaping uses, the rain barrel or cistern should be sited upgradient of the landscaping areas or on a raised stand. Gravity-fed operations may also be used for indoor residential uses, such as laundry, that do not require high water pressure. For larger-scale landscaping operations, locating a cistern on the roof or uppermost floor may be the most cost efficient way to provide water pressure.
|Cisterns should be placed on or in native, rather than fill, soils. If placement on fill slopes is necessary, a geotechnical analysis is needed. Underground tanks and the pipes conveying rainwater to and from them, including overflow systems, should either be located below the local frost penetration depth (MTO, 2005), or insulated to prevent freezing during winter
|Rainwater harvesting systems can be an effective stormwater BMP for roof runoff at sites where land uses or activities at groundlevel have the potential to generate highly contaminated runoff
|Rainwater harvesting system overflow devices should be designed to avoid causing ponding or soil saturation within three (3) metres of building foundations
|The presence of underground utilities (e.g., water supply pipes, sanitary sewers, natural gas pipes, cable conduits, etc.), may constrain the location of underground rainwater storage tanks.
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|Underground cisterns should be placed in areas without vehicular traffic. Tanks under roadways, parking lots, or driveways must be designed for the live loads from heavy trucks, a requirement that could significantly increase construction costs.
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