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Line 12:
Line 12: − + − + + + − Perforated catch basins and maintenance holes are a design variation, where the riser is perforated to allow runoff to infiltrate into the underlying soil. Line 24:
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→Planning
'''The fundamental components of an exfiltration system are:'''
'''The fundamental components of an exfiltration system are:'''
*[[pretreatment| pre-treatment devices]] to retain coarse sediment, trash, debris and floatables,
*[[pretreatment| pre-treatment devices]] to retain coarse sediment, trash, debris and floatables,
*perforated [[pipes]] connected to maintenance holes and catch basins,
*perforated [[pipes]] embedded in washed gravel connected to maintenance holes and catch basins,
*a gently sloping granular [[reservoir aggregate| storage reservoir]] below the perforated pipe.
*a gently sloping granular [[reservoir aggregate| storage reservoir]] below the perforated pipe.
'''Optional components include:'''
'''Optional components include:'''
*[[Geotextile]] to prevent migration of fines into the reservoir.
*[[Geotextile]] to prevent migration of fines into the reservoir;
*Trench plugs to help disperse stormwater throughout the trench and enhance infiltration; and
*Perforated maintenance hole or catch basin risers.
Exfiltration systems can be used in place of conventional storm sewer pipes, where topography, water table depth, and [[water quality]] conditions are suitable. They are suitable for treating runoff from roofs, walkways, parking lots and low to medium traffic roads, with adequate [[pretreatment]].
Exfiltration systems can be used in place of conventional storm sewer pipes, where topography, water table depth, and [[water quality]] conditions are suitable. They are suitable for treating runoff from roofs, walkways, parking lots and low to medium traffic roads, with adequate [[pretreatment]].
Exfiltration systems can also be referred to as perforated pipe systems, clean water collector systems and percolation drainage systems.
Exfiltration systems can also be referred to as perforated pipe systems, clean water collector systems and percolation drainage systems.
If properly located, designed and maintained, perforated pipe systems can greatly reduce runoff volume while having little or no surface footprint, which helps to conserve highly valued developable land.
If properly located, designed and maintained, perforated pipe systems can greatly reduce runoff volume while having little or no surface footprint, which helps to conserve highly valued developable land.
Systems should be located below shoulders of roadways, [[permeable paving]] or [[swales]] where they can be readily excavated for servicing. An adequate subsurface area outside of the 4 m setback from building foundations and suitable distance from other underground utilities must be available.
Systems should be located below shoulders of roadways, [[permeable pavements]] or [[swales]] where they can be readily excavated for servicing. An adequate subsurface area outside of the 4 m setback from building foundations and suitable distance from other underground utilities must be available.
===Site Topography===
===Site Topography===