Selection Matrix: Step 6

Step 6. Pollutant Removal

This matrix examines the capability of each STP option to remove specific pollutants from stormwater runoff. The matrix includes data for:

Total Suspended Solids
Total Phosphorous
Total Nitrogen
Metals
Bacteria

For more information on these and other pollutants, please consult the Pollutant Removal Database (in .pdf format)

In some communities, on-site load calculation is required, and this matrix is critical. In others, these values may be replaced with relative (i.e., "high, low, moderate") pollutant removals. Also, a community may choose to focus on only one or two target pollutants to protect a specific resource.

STP Selection Matrix 6. Pollutant Removal
STP Group	TSS	TP	TN	Metals¹	Bacteria
Ponds	80	51	33	62	70
Wetlands	76	49	30	42	78²
Filters³	86	59	38	69	37²
Infiltration	95²	70	51	99²	N/A
Open Channels ⁴	81	34²	84^2,5	61	-25²
1: Average of zinc and copper. Zinc only for infiltration practices. 2: Based on fewer than five data points. 3: Excludes vertical sand filters and filter strips. 4: Highest removal rates for dry swales 5: No data available for grass channels N/A: Data not available