2,681
edits
Changes
Jump to navigation
Jump to search
Line 340:
Line 340: − +
→Underdrain
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.
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]]===
*Recommended where native soil infiltration rate is less than 15 mm/h (hydraulic conductivity < 1x10-6 cm/s) and needed for non-infiltrating, filtration only designs.
*Recommended where native soil infiltration rate is less than 15 mm/h (hydraulic conductivity < 1x10-6 cm/s) and needed for non-infiltrating, filtration only designs.
*Typically comprised of a length of perforated pipe embedded near the top of the storage reservoir, with an overlying choker layer of medium-sized aggregate, and structures to provide inspection and maintenance access.
*Typically comprised of a length of perforated pipe embedded near the top of the storage reservoir, with an overlying choker layer of medium-sized aggregate, and structures to provide inspection and maintenance access.