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Line 26: ===Designing with constraints==={{textbox|Infiltration can still be optimized over 'tight' soils with infiltration rates ≤ 15 mm/hr:*See [[Underdrains| underdrains]] for [[Bioretention| bioretention]] and [[Trees| tree pits, trenches and soil cells]], and *Results from STEP studies of infiltration practices on [[low permeability soils]]}}{{textbox|Where infiltration is impossible, LID design alternatives exist which can still capture and retain stormwater:*[[Stormwater planters]]*[[Rainwater harvesting]]*[[Green roofs]]*[[Blue roofs]]
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Infiltration of stormwater into underlying 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|Infiltration is promoted through a number of LID BMPs:
{{textbox|Drainage via infiltration be achieved through a number of LID BMP types:
*[[Infiltration chambers]] (underground)
*[[Infiltration chambers]] (underground)
*[[Infiltration trenches]] (underground)
*[[Infiltration trenches]] (underground)
*[[Exfiltration trenches| Exfiltration systems]] (underground)
*[[Exfiltration trenches| Exfiltration systems]] (underground)
*[[Bioretention]] (surface)
*[[Bioretention]] (surface, full- or partial-infiltration design variations)
*[[Bioswales]] (surface)
*[[Bioswales]] (surface, full- or partial-infiltration design variations)
*[[Trees| Soil cells]] (surface)
*[[Permeable pavements| Permeable pavements]] (surface, full- or partial-infiltration design variations)
*[[Permeable paving| Permeable pavements]] (surface)
*[[Stormwater Tree Trenches|Stormwater tree trenches]] (surface)
*[[Enhanced swales]] featuring check dams (surface)
*[[Dry ponds]] or infiltration basins (surface)
*[[Dry ponds]] or infiltration basins (surface)
}}
}}
#contaminated soils or sites with high risk of contamination from on-site activities (i.e. pollution hot spots),
#contaminated soils or sites with high risk of contamination from on-site activities (i.e. pollution hot spots),
#in areas of known or implied karst topography,
#in areas of known or implied karst topography,
#on unstable or steep slopes (15 to 20%),
#on unstable or steep slopes (>15%),
# to treat construction site runoff,
# to treat construction site runoff,
#to treat combined sewer overflows,
#to treat combined sewer overflows,
#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).
<br>
<br>
See [[Site considerations]] for further guidance on potential site constraints and LID facility type selection and design considerations.
===Designing with constraints===
{{textbox|Infiltration facilities can be effective on low permeability soils with infiltration rates ≤ 15 mm/hr:
*See [[Underdrains| underdrains]] and
*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
#the seasonal high groundwater level (i.e. water table) comes within 1 m below the bottom of the proposed BMP.
#the seasonal high groundwater level (i.e. water table) comes within 1 m below the bottom of the proposed BMP.
}}
}}
{{:Groundwater}}
==Planning==
==Planning==
===Hydrogeology===
===Hydrogeology===
The Conservation Authorities Geoscience Group has prepared a guidance document which attempts to standardize the hydrogeological study requirements for development applications made to Conservation Authorities. It is a helpful guide for all low impact development applications which include infiltration. It is provided with the caveat that not all sections or content are necessary or appropriate for every case. Pre-consultation with your Conservation Authority and municipality is strongly recommended in all cases.
The Conservation Authorities Geoscience Group has prepared a guidance document which attempts to standardize the hydrogeological study requirements for development applications made to Conservation Authorities. It is a helpful guide for all low impact development applications which include infiltration. It is provided with the caveat that not all sections or content are necessary or appropriate for every case. Pre-consultation with your local conservation authority and municipality is strongly recommended in all cases.
'''[http://www.lsrca.on.ca/Shared%20Documents/permits/hydrogeological%20_guidelines.pdf?pdf=Hydrogeological-Guidelines Hydrogeological Assessment Submissions Conservation Authority Guidelines for Development Applications]'''
'''[http://www.lsrca.on.ca/Shared%20Documents/permits/hydrogeological%20_guidelines.pdf?pdf=Hydrogeological-Guidelines Hydrogeological Assessment Submissions Conservation Authority Guidelines for Development Applications]'''
==See also==
==See also==
*[[Groundwater]]
*[[Site considerations]]
[[category:Infiltration]]
[[category:Infiltration]]