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

Bioretention Type1 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

1The terminology has been changed from the original manual. The original Manual terminology is shown in parenthesis. For more information, see Bioretention terminology