Changes

Underdrains comprise a length of perforated [[pipe]] embedded into a layer of [[reservoir aggregate]]. They are an optional component of [[bioretention]] systems, [[bioswales]], [[permeable pavements]] and [[Stormwater Tree Trenches |stormwater tree trenches]] and a required component of [[stormwater planters]]. Their design varies according to the drainage requirements of the installation, but all require standpipes or structures that provide access to the perforated pipe for inspection and maintenance purposes.  Underdrain perforated pipes should be located below the frost line to reduce the threat of ice clogging. Ontario provincial standard drawings of frost penetration depth are available from the [https://www.library.mto.gov.on.ca/SydneyPLUS/TechPubs/Portal/tp/opsViews.aspx Ministry of Transportation] as OPSD 3090.100 for northern Ontario <ref> Ministry of Transportation. 2010. Foundation Frost Penetration Depths for Northern Ontario. OPSD 3090.100. Nov 2010. Rev.1. https://www.library.mto.gov.on.ca/SydneyPLUS/TechPubs/Portal/tp/opsViews.aspx </ref> and OPSD 3090.101 for southern Ontario <ref> Ministry of Transportation. 2010. Foundation Frost Penetration Depths for Southern Ontario. OPSD 3090.101. Nov 2010. Rev.1. https://www.library.mto.gov.on.ca/SydneyPLUS/TechPubs/Portal/tp/opsViews.aspx </ref>.

Underdrains comprise a length of perforated [[pipe]] embedded into a layer of [[reservoir aggregate]]. They are an optional component of [[bioretention]] systems, [[bioswales]], [[permeable pavements]] and [[Stormwater Tree Trenches |stormwater tree trenches]], and a required component of [[stormwater planters]]. Their design varies according to the drainage requirements of the installation, but all require standpipes or structures that provide access to the perforated pipe for inspection and maintenance purposes.  Underdrain perforated pipes should be located below the frost line to reduce the threat of ice clogging. Ontario provincial standard drawings of frost penetration depth are available from the [https://www.library.mto.gov.on.ca/SydneyPLUS/TechPubs/Portal/tp/opsViews.aspx Ministry of Transportation] as OPSD 3090.100 for northern Ontario <ref> Ministry of Transportation. 2010. Foundation Frost Penetration Depths for Northern Ontario. OPSD 3090.100. Nov 2010. Rev.1. https://www.library.mto.gov.on.ca/SydneyPLUS/TechPubs/Portal/tp/opsViews.aspx </ref> and OPSD 3090.101 for southern Ontario <ref> Ministry of Transportation. 2010. Foundation Frost Penetration Depths for Southern Ontario. OPSD 3090.101. Nov 2010. Rev.1. https://www.library.mto.gov.on.ca/SydneyPLUS/TechPubs/Portal/tp/opsViews.aspx </ref>.

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