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Line 37: − − ==Planning== − ===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 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]''' − − ==Beginning an infiltration BMP design?== − See [[Design infiltration rates]] − − ==See also== − *[[Site considerations]] −
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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, partial-infiltration design variation)
*[[Enhanced swales]] or [[Swales |swales]] featuring check dams (surface)
*[[Dry ponds]] or infiltration basins (surface)
*[[Dry ponds]] or infiltration basins (surface)
}}
}}
#over-swelling clays or unstable subsoils,
#over-swelling clays or unstable subsoils,
#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 |karst topography]],
#on unstable or steep slopes (>15%),
#on unstable or steep slopes (>15%),
# to treat construction site runoff,
# to treat construction site runoff,
#in areas where the ecology and natural hydrology are dependent upon surface water,
#in areas where the ecology and natural hydrology are dependent upon surface water,
#in areas where increased infiltration will result in elevated groundwater levels that will damage critical utilities or private property, or
#in areas where increased infiltration will result in elevated groundwater levels that will damage critical utilities or private property, or
#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 source water protection plans (e.g. should not be used to treat pavement runoff within wellhead protection area B, 2 year time of travel zones, nor within groundwater quality issue contributing areas where Sodium or Chloride is a threat).
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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
}}
}}
{{:Groundwater}}
{{:Groundwater}}
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[[category:Infiltration]]
[[category:Infiltration]]