Changes

* Percent organic matter shall be 3-5%, by dry weight.

* Percent organic matter shall be 3-5%, by dry weight.

* Growing medium compacted to 80-90% below the tree root ball to prevent settling.

* Growing medium compacted to 80-90% below the tree root ball to prevent settling.

* Bioretention filter media (see [https://wiki.sustainabletechnologies.ca/wiki/LID_BMP_Fact_Sheets#Bioretention| Bioretention Fact Sheet]) may be suitable for use as growing medium, depending on climate and tree species.

* Bioretention filter media may be suitable for use as growing medium, depending on climate and tree species (see [[Bioretention: Filter media]]).

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|'''Modular Soil Support System'''

|'''Modular Soil Support System'''

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* Geotextile, geogrid or combinations are typically used on top of modular soil support structures and along the sides of the trench to separate growing or structural soil mediums from native soil or aggregate backfill. Geotextile and geogrid should not be installed on sides adjacent to pervious landscaped areas to provide opportunities for tree roots to grow outside the trench in these locations.

* Geotextile, geogrid or combinations are typically used on top of modular soil support structures and along the sides of the trench to separate growing or structural soil mediums from native soil or aggregate backfill. Geotextile and geogrid should not be installed on sides adjacent to pervious landscaped areas to provide opportunities for tree roots to grow outside the trench in these locations.

* Geotextile material specifications should conform to Ontario Provincial Standard Specification (OPSS)

* Geotextile material specifications should conform to Ontario Provincial Standard Specification (OPSS) 1860 for Class II geotextile fabrics.

1860 for Class II geotextile fabrics.

* Geotextile, geogrid or combination products in contact with modular soil support system structures should be according to manufacturer’s specifications.

* Geotextile, geogrid or combination products in contact with modular soil support system structures should be according to manufacturer’s specifications.

* Geotextile installed on tree trench sides and around perforated distribution and underdrain pipes should be woven monofilament or non-woven needle punched fabrics. Woven slit film and non-woven heat bonded fabrics should not be used as they are prone to clogging.

* Geotextile installed on tree trench sides and around perforated distribution and underdrain pipes should be woven monofilament or non-woven needle punched fabrics. Woven slit film and non-woven heat bonded fabrics should not be used as they are prone to clogging.

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* Should be minimum 150 mm dia. perforated HDPE or equivalent material, smooth interior wall and continuously perforated with geotextile sock.

* Should be minimum 150 mm dia. perforated HDPE or equivalent material, smooth interior wall and continuously perforated with geotextile sock.

* A standpipe from the underdrain pipe to the growing medium or pavement surface can be used for inspection and maintenance. The top of the standpipe should be covered with a sealable cap and secured with a vandal-proof fastener.

* A solid standpipe connected to the underdrain pipe and extending to the growing medium or pavement surface can be used for inspection and maintenance access. The top of the standpipe should be covered with a sealable cap or plug and secured with a vandal-proof fastener.

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|'''Stormwater Distribution Pipe'''

|'''Stormwater Distribution Pipe'''