Summary of Bioretention Variants for Permeability of Native Soils and Potential Land use Pollutant Loading
(Link to this table)

Bioretention Type Variant Underlying Soil Performance Criteria
Bioinfiltration
(Infiltration/Recharge Facility)
No underdrain Higher recharge potential (facility drain time without underdrain is 48 hours or less)
Biofiltration with underdrain at the bottom (Filtration/Partial Recharge Facility) Underdrain Lower recharge potential (facility drain time without underdrain is > 48 hours)
Biofiltration with internal water storage underdrain Lower recharge potential (facility drain time without underdrain is >48 hours)
Biofiltration with elevated underdrain (Infiltration/Filtration/Recharge Facility) Elevated underdrain Higher nutrient loadings and/or quantity control
Biofiltration with liner (Filtration Only Facility) Underdrain with liner Hot Spot Treatment