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Infiltration of stormwater into underlying native subgrade soils is one mechanism to achieving MECP [[runoff volume control targets]]. In many areas of Ontario, where municipal supplies of potable water are drawn from aquifers, it's also an important mechanism for groundwater recharge.

Infiltration of stormwater into underlying native subgrade soils is one mechanism to achieving MECP [[runoff volume control targets]]. In many areas of Ontario, where municipal and private drinking water supplies are drawn from aquifers, it's also an important mechanism for groundwater recharge.

{{textbox|Drainage via infiltration be achieved through a number of LID BMP types:

{{textbox|Drainage via infiltration be achieved through a number of LID BMP types:

*[[Infiltration chambers]] (underground)

*[[Infiltration chambers]] (underground)

*[[Bioretention]] (surface, full- or partial-infiltration design variations)

*[[Bioretention]] (surface, full- or partial-infiltration design variations)

*[[Bioswales]] (surface, full- or partial-infiltration design variations)

*[[Bioswales]] (surface, full- or partial-infiltration design variations)

*[[Permeable pavements| Permeable pavements]] (surface, full- or partial-infiltration design variations)

*[[Permeable pavements| Permeable pavements]] (surface, full- or partial-infiltration design variations)

*[[Stormwater Tree Trenches|Stormwater tree trenches]] (surface)

*[[Stormwater Tree Trenches|Stormwater tree trenches]] (surface)

*[[Dry ponds]] or infiltration basins (surface)

*[[Dry ponds]] or infiltration basins (surface)

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#where prohibitions and/or restrictions exist per approved Drinking Water Source Protection Plans (e.g. should not be used to treat pavement runoff within 2 year time of travel wellhead protection areas; see MOECC guidance).

#where prohibitions and/or restrictions exist per approved Drinking Water Source Protection Plans (e.g. should not be used to treat pavement runoff within 2 year time of travel wellhead protection areas; see MOECC guidance).

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See [[Site considerations]] for further guidance on potential site constraints and LID practice design considerations.  

See [[Site considerations]] for further guidance on potential site constraints and LID facility type selection and design considerations.  

===Designing within constraints===

===Designing with constraints===

{{textbox|Infiltration can still be optimized on low permeability soils with infiltration rates ≤ 15 mm/hr:

{{textbox|Infiltration facilities can be effective on low permeability soils with infiltration rates ≤ 15 mm/hr:

*See [[Underdrains| underdrains]] for [[Bioretention| bioretention]] and [[Stormwater Tree Trences|stormwater tree trenches]], and  

*See [[Underdrains| underdrains]] and  

*Results from STEP studies of infiltration practices on [[low permeability soils]]

*Results from STEP studies of infiltration facilities located on [[low permeability soils]] in Ontario.

Infiltration facilities should be designed with modifications where:  

Infiltration facilities should be designed with modifications where:  

#the underlying bedrock is within 1 m below the bottom of the proposed BMP, or

#the underlying bedrock is within 1 m below the bottom of the proposed BMP, or