Structural BMP use in karst settings

Considerations for structural BMP use in karst settings.
Link to this table

BMP	Karst considerations
Bioretention	If containment levels remain high after treatment or if water inflow presents a threat, an underdrain and-or use of a synthetic or other impermeable membrane liner should be considered to seal the bottom of the system.
Media filter	If containment levels remain high after treatment or if water inflow presents a threat, an underdrain and-or use of a synthetic or other impermeable membrane liner should be considered to seal the bottom of the system.
Vegetative filter	Avoid water ponding Should be engineered to avoid channel erosion and optimize pollutant removal
Infiltration trench or basin	Not typically recommended in active karst areas due to sinkhole formation and inadequate treatment by a scarcity of underlying soils If used, should have supporting geotechnical investigations and calculations Pre-treatment should be extensive to limit risk of groundwater contamination Local review authority should be consulted for approval
Stormwater ponds	Should be constructed with a synthetic or clay liner in active karst areas Should have supporting geotechnical investigations and calculations Should be limited to a maximum ponding depth (e.g. < 10 feet)
Constructed wetlands	Should be constructed with a synthetic or clay liner in active karst areas Should have supporting geotechnical investigations and calculations Should be limited to a maximum ponding depth (e.g. < 10 feet)