Changes

Infiltration chambers are an ideal technology for installing below any type of surface or landscape suitable for receiving and infiltrating large volumes of stormwater. Components typically include proprietary chamber system parts that provide large water storage volume per unit area, [[Reservoir aggregate| clear stone aggregate]] to construct base and embed chambers, [[Geotextile| geotextile]], [[Pretreatment| pretreatment devices]], and structures to access inlets, outlets, pretreatment devices and the chambers themselves for operation and maintenance. Optional components include a flow restrictor to control the release rate of the facility, and surface drains to safely convey flows in excess of the storage capacity of the design.<br>

Infiltration chambers are an ideal technology for installing below any type of surface or landscape suitable for receiving and infiltrating large volumes of stormwater. Components typically include proprietary chamber system parts that provide large water storage volume per unit area, [[Reservoir aggregate| clear stone aggregate]] to construct base and embed chambers, [[Geotextile| geotextile]], [[Pretreatment| pretreatment devices]], and structures to access inlets, outlets, pretreatment devices and the chambers themselves for operation and maintenance. Optional components include a flow restrictor to control the release rate of the facility, and surface drains to safely convey flows in excess of the storage capacity of the design.<br>

Design and operation and maintenance program assumptions used to generate cost estimates are based on tool default values and the following STEP recommendations:

Design and operation and maintenance program assumptions used to generate cost estimates are based on tool default values and the following STEP recommendations:

* Native soil infiltration rates for Full, and Partial Infiltration Design scenarios were assumed to be 20 mm/h and 10 mm/h respectively, and a safety factor of 2.5 was applied to calculate the design infiltration rate.  

* Native soil infiltration rates for Full, and Partial Infiltration Design scenarios were assumed to be 20 mm/h and 10 mm/h respectively, and a safety factor of 2.5 was applied to calculate the design infiltration rate.  

* Operation and maintenance (O&M) cost estimates assume annual inspections, removal of trash and debris twice a year, removal of sediment from pretreatment structures annually, and removal of weeds twice a year (where applicable). Verification inspections are included every 5 years to confirm adequate maintenance, and every 15 years to confirm adequate drainage performance through in-situ surface infiltration rate testing (where applicable)

* Operation and maintenance (O&M) cost estimates assume annual inspections, removal of trash and debris twice a year, and removal of sediment from pretreatment structures annually. Verification inspections are included every 5 years to confirm adequate maintenance, and every 15 years to confirm adequate drainage performance through in-situ chamber system water level monitoring during natural storm events.

* Designed with an impervious drainage area to treatment facility area ratio of between 5:1 and 20:1.  

* Hydrodynamic separators ([[Oil and grit separator| oil and grit separators]] and isolated chamber row as [[Pretreatment| pretreatment]].

** A maximum ratio of 10:1 is recommended from facilities receiving road or parking lot runoff.

* Infiltration chamber system length of 5 metres.

* Facilities receiving road or parking lot runoff should not be located within the two year time-of-travel of [[Source Water Protection|wellhead protection areas]].

* Infiltration chamber system height of 0.762 metres.

* 50 mm dia. clear stone aggregate bedding depth (below and above chamber system) of 152 millimetres.

* Two (2) maintenance holes providing access to infiltration chamber system inlet and outlet structures.

* Pretreatment device options include leaf screens for roof runoff, and [[vegetated filter strips]], [[enhanced swales|grass swales]] or [[oil and grit separators]] for road runoff.

* The [[inlet]] and [[Overflow|overflow outlet]] to the facility should be installed below the maximum [[Winter Management|frost penetration depth]] to prevent freezing.

* The overflow outlet can be the pipe inlet that backs up when capacity's reached (discharging to pervious area), or it can be a pipe connected to a storm sewer.

* Outlet pipes must have capacity equal to or greater than the inlet.

* Capped and vertical non-perforated pipes connected to the inlet and outlet pipes are recommended for inspecting and flushing as part of routine maintenance.

* Manholes and inspection ports should be installed in infiltration chambers to provide access for monitoring and maintenance activities (Tool defaults).

* Compaction, erosion and sediment control are main concerns during construction.  Facilities are vulnerable to failure during the construction phase. Construction sediment can clog the excavation if construction instructions incorrectly followed.

===Notes===

===Notes===