BMP pollutant removal for total nitrogen

Median pollutant removal of total nitrogen by stormwater treatment practices. Values represent percentage of incoming pollutant load that is removed. Source: Minnesota Stormwater Manual. Manual data was based on information from ASCE/EPA International Database; Winer (2000)

BMP group	Total nitrogen
Bioretentiona	45
Filtrationb	35
Infiltrationc	100
Stormwater ponds	30
Stormwater wetlands	30

^aData based on fewer than five monitoring studies
^bExcludes vertical sand filters and filter strips
^cNote that 100% is assumed for all infiltration, but only for that portion of the flow fully treated in the infiltration facility; by-passed runoff does not receive any treatment.