Event mean concentrations for total phosphorus

Information: This page was updated December 26, 2019. Read table caption below.

Event mean concentrations for total phosphorus. To see supporting information used to derive this table, link here.
Link to this table

Land cover/land use	Range (mg/L)	Recommended value (mg/L)1	Notes
Commercial	0.20 - 0.34	0.200	If applicable to models being used, adjust curve numbers/runoff coefficients when calculating loads
Industrial	0.23 - 0.55	0.235	If applicable to models being used, adjust curve numbers/runoff coefficients when calculating loads Adjust upward if specific phosphorus sources exist
Residential	0.26 - 0.38	0.325	Concentrations vary widely depending on local conditions
High-density/Multi-family residential	0.28 - 0.40	Calculate	Insufficient information to recommend a specific emc Concentrations vary widely depending on local conditions
Medium density residential	0.18 - 0.40	Calculate	Insufficient information to recommend a specific emc Concentrations vary widely depending on local conditions
Low density residential	0.24 - 0.40	Calculate	Insufficient information to recommend a specific emc Concentrations vary widely depending on local conditions
Freeways/transportation	0.25 - 0.45	0.28	Concentrations vary widely depending on inputs Adjust upward for areas receiving large inputs of road salt or sediment or having very heavy traffic loads Adjust downward for low traffic areas or areas with reduced inputs (e.g. little road salt application, limited truck traffic)
Mixed	0.16 - 0.84	0.29	Residential land use was the primary land use in most studies that cited values for mixed land use If the study area can be delineated into specific land uses and impervious area for each land use is know, we recommend calculating the emc
Parks and recreation		Use value for open space or calculate	emc will be a function of vegetative cover Adjust upward if street tree canopy cover is high or pervious areas are primarily grass on compacted soils
Open space	0.12 - 0.31	0.19
Conventional roof	0.01 - 0.20	0.030
Institutional	0.14 - 0.422	See note	Use low values in range (0.200 mg/L or less) for facilities such as campuses, where there is considerable pervious area Use high values in range (0.30 mg/L or greater) for areas with considerable impervious surface, such as sports facilities or facilities with large parking areas
Forest/shrub/grassland	0.03 - 0.45	0.09	Concentrations are likely to vary with season in areas with fall leaf drop
Open water and wetlands		see Notes (next column)	If data exist, use the phosphorus concentration for the water body of interest If data for a specific lake do not exist, use data from similar lakes in the area emcs for wetlands will typically be higher than for lakes in an area. Consider using a value equal to 2 times the value for lakes in an area.
Cropland (row crops)	0.126-1.348		Median from our review = 0.533
Pasture	0.35-0.45