Changes

See [[Filter media]] for detailed guidance on different blends, required performance criteria, and specifications and laboratory tests for blend components and the filter media itself.

See [[Filter media]] for detailed guidance on different blends, required performance criteria, and specifications and laboratory tests for blend components and the filter media itself.

===Geotextile===

===[[Geotextiles]]===

To avoid clogging, the use of geotextile should be avoided exept for a strip over the perforated pipe or on the sides of the bioretention if necessary. For pipes with 360° perforations place a strip of geotextile over the pipe to reduce the migration of fines from overlying media. Geotextile used for weed control (i.e. landscape fabric) in filter bed media or under mulch should be avoided.

To avoid clogging, the use of geotextile on the bottom of bioretention facilities should be avoided. Geotextile socks should be installed on underdrain pipes with 360 degree perforations. Alternatively a strip of geotextile may be placed over the pipe to limit migration of fines from the overlying filter media into the pipe. Geotextile may be installed on the sides of the bioretention cell to maintain separation between backfill materials during construction. Geotextile used for weed control (i.e. landscape fabric) within the filter media bed or under mulch should be avoided.

Geotextile that is used should have material specifications that conform to Ontario Provincial Standard Specification (OPSS) 1860 for Class II geotextile fabrics. Should be woven monofilament or non-woven needle punched fabrics.

Geotextile that is used should have material specifications that conform to Ontario Provincial Standard Specification (OPSS) 1860 for Class II geotextile fabrics. Should be woven monofilament or non-woven needle punched fabrics. See [[Geotextiles]] for further guidance.

===Underdrain===

===Underdrain===