Design process for selecting the appropriate liner level.
Link to this table

Condition Design level Note
Filtration BMP with less than 3 feet of separation to seasonal saturated soil or bedrock 1 Required under the Construction Stormwater permit
BMP in confirmed PSH with high or very high groundwater pollution potential 1
Karst terrain with high or very high groundwater pollution potential 1
Maintain permanent pool in areas underlain by geologic material that is fractured or has a high infiltration rate 2
Separation distances cannot be achieved 2
Separate tree BMP from road, parking lot, sidewalk or adjacent walls or building foundation 2 To prevent tree root intrusion. See link