Changes

Bioretention with an [[underdrain]] is a popular choice over 'tighter' soils where infiltration rates are ≤ 15 mm/hr. Including an perforated [[pipe]] in the [[reservoir aggregates|reservoir]] layer help to empty the facility between storm events, even over [[low permeability soils]]. The drain discharges to a downstream point, which could be an underground [[infiltration trench]] or [[chamber]] facility. Volume reduction is gained through infiltration and [[evapotranspiration]]. By raising the outlet of the discharge pipe the bottom portion of the BMP can only drain through infiltration. This creates a fluctuating anaerobic/aerobic environment which promotes denitrification. Increasing the period of storage has benefits for promoting infiltration, but also improves water quality for catchments impacted with nitrates. A complimentary technique is to use fresh wood mulch, which also fosters denitrifying biological processes.

Bioretention with an [[underdrain]] is a popular choice over 'tighter' soils where infiltration rates are ≤ 15 mm/hr. Including an perforated [[pipe]] in the [[reservoir aggregates|reservoir]] layer help to empty the facility between storm events, even over [[low permeability soils]]. The drain discharges to a downstream point, which could be an underground [[infiltration trench]] or [[chamber]] facility. Volume reduction is gained through infiltration and [[evapotranspiration]]. By raising the outlet of the discharge pipe the bottom portion of the BMP can only drain through infiltration. This creates a fluctuating anaerobic/aerobic environment which promotes denitrification. Increasing the period of storage has benefits for promoting infiltration, but also improves water quality for catchments impacted with nitrates. A complimentary technique is to use fresh wood mulch, which also fosters denitrifying biological processes.

===[[Inlets]] and pretreatment options===  

===Inlets and pretreatment options===  

Options for [[pretreatment]] include:

Options for [[pretreatment]] include:

*A [[gravel diaphragm]] for sheet flow

*A [[gravel diaphragm]] for sheet flow

*An [[Oil and grit separators|oil and grit separator]] for concentrated underground flow

*An [[Oil and grit separators|oil and grit separator]] for concentrated underground flow

Simple (non-treating) inlets include:

Simple (non-treating) [[inlets]] include:

*Sheet flow from a depressed curb

*Sheet flow from a depressed curb

*One of more [[curb cuts]]

*One of more [[curb cuts]]

*Covered drains

*Covered drains

===Overflow routing===

===Overflow routing===

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