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Line 9: − + − #Where the seasonal high groundwater level comes within 1 m below the bottom of the proposed BMP,<br>Or in areas where increased infiltration will result in elevated groundwater levels, which can be demonstrated to damage critical utilities or private property,+ − #Over swelling clays or unstable sub-soils,+ − + − + − + − + + +
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===Constraints===
===Constraints===
Infiltration practices are not recommended:
Infiltration practices are not recommended:
#Where the bedrock is within 1 m below the bottom of the proposed BMP,
#over swelling clays or unstable sub-soils,
#over contaminated soils or sites with high risk of contamination from onsite activities,
#in flood prone areas where the wastewater system is sensitive to groundwater conditions causing sewer backups, and where LID BMPs have been found to be ineffective,
#Over contaminated soils or sites with high risk of contamination from onsite activities,
#in areas where the ecology and natural hydrology are dependent upon surface water,
#In flood prone areas where the wastewater system is sensitive to groundwater conditions causing sewer backups, and where LID BMPs have been found to be ineffective,
#in areas where increased infiltration will result in elevated groundwater levels, which can be demonstrated to damage critical utilities or private property, or
#In areas where the ecology and natural hydrology are dependent upon surface water,
#where prohibitions and/or restrictions exist per approved Source Protection Plans (see MOECC guidance).
#Where prohibitions and/or restrictions exist per approved Source Protection Plans (see MOECC guidance).
Infiltration facilities should be designed with drainage modifications where:
#the underlying bedrock is within 1 m below the bottom of the proposed BMP, or
#the seasonal high groundwater level comes within 1 m below the bottom of the proposed BMP.
===Designing within constraints===
===Designing within constraints===
{{TextBox|1= Infiltration can still be optimized over 'tight' soils with infiltration rates ≤ 15 mm/hr:
{{TextBox|1= Infiltration can still be optimized over 'tight' soils with infiltration rates ≤ 15 mm/hr: