For a discussion of event mean concentrations, see Stormwater pollutant concentrations and event mean concentrations

Event mean concentrations for total phosphorus

For a discussion of event means concentrations for phosphorus, see Event mean concentrations of total and dissolved phosphorus in stormwater runoff

Event mean concentrations for total phosphorus.
Link to this table

Land cover/land use Range (mg/L) Recommended value (mg/L) 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 Calculate1
  • Insufficient information to recommend a specific emc
  • Concentrations vary widely depending on local conditions
Medium density residential 0.18 - 0.40 Calculate1
  • Insufficient information to recommend a specific emc
  • Concentrations vary widely depending on local conditions
Low density residential 0.24 - 0.40 Calculate1
  • Insufficient information to recommend a specific emc
  • Concentrations vary widely depending on local conditions
Freeways/transportation 0.25 - 0.45 0.280
  • 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 0.290
  • 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 0.190
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 0.090 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 2 Median from our review = 0.533
Pasture 0.35-0.45 2

1The link takes you to information on calculating event mean concentrations for areas with multiple land uses.
2Our literature review was not extensive enough to warrant a specific recommend emc for this land use


Event mean concentrations for dissolved phosphorus

For a discussion of event means concentrations for phosphorus, see Event mean concentrations of total and dissolved phosphorus in stormwater runoff

Summary of dissolved phosphorus event mean concentrations from various studies. There is inadequate information to provide recommended emcs for different land uses.
Link to this table

Study Land cover/land use Range (mg/L) Mean Median Number of samples
Dallas-Fort Worth1 Commercial 0.01-0.47 0.09 0.06 42
Dallas-Fort Worth Industrial 0.03-0.45 0.14 0.09 63
Dallas-Fort Worth Residential 0.04-0.84 0.25 0.21 77
Forth Worth2 Transportation 0.11 28
Twin Cities3 Mixed 0.01-1.4 0.2 0.15 147
Madison4 Medium density residential 0.52 0.61 25
Madison4 Medium density residential 0.4 0.14 25
Madison4 Medium density residential 0.14 0.04 25
Madison4 Medium density residential 0.05 0.03 25
Madison4 Medium density residential 0.04 0.02 25
Madison4 Medium density residential 0.03 0.02 25
Madison4 Medium density residential 0.04 0.02 25
Madison4 Medium density residential 1.54 0.81 25
Madison4 Medium density residential 0.12 0.08 25
Madison4 Medium density residential 0.11 0.07 25
Madison4 Medium density residential 0.11 0.07 25
US EPA Nurp Study5 Residential 0.143
US EPA Nurp Study5 Mixed 0.056
US EPA Nurp Study5 Commercial 0.08
US EPA Nurp Study5 Open 0.026
New York6 Residential 0.20 738
New York6 Commercial 0.18 323
New York6 Industrial 0.16 325
New York6 Open 0.16 44
Capitol Region Watershed District7 Mixed 0.020 - 0.888 0.073 0.052 89
Capitol Region Watershed District7 Mixed 0.020 - 0.565 0.108 0.087 120
Capitol Region Watershed District7 Mixed 0.020 - 0.506 0.074 0.059 112
Capitol Region Watershed District7 Mixed 0.020 - 0.361 0.073 0.053 121
Capitol Region Watershed District7 Mixed 0.005 -- 0.182 0.019 0.012 195
Capitol Region Watershed District7 Mixed 0.020 - 0.758 0.102 0.072 69
Capitol Region Watershed District7 Mixed 0.020 - 1.10 0.072 0.053 115
Capitol Region Watershed District7 Mixed 0.020 - 0.60 0.099 0.057 113
Capitol Region Watershed District7 Mixed 0.020 - 0.499 0.071 0.046 138

1Urban Stormwater Quality, Event-Mean Concentrations, and Estimates of Stormwater Pollutant Loads, Dallas-Fort Worth Area, Texas. 1992–93 Stanley Baldys III, T.H. Raines, B.L. Mansfield, and J.T. Sandlin U.S. Geological Survey Water-Resources Investigations Report 98–4158.
2Computed and Estimated Pollutant Loads, West Fork Trinity River, Fort Worth, Texas, 1997. United States Geological survey. Water Resources Investigations Report 01–4253
3Brezonik and stadelman. 2002. Analysis and predictive models of stormwater runoff volumes, loads, and pollutant concentrations from watersheds in the Twin Cities metropolitan area, Minnesota, USA. Water Research Volume 36, Issue 7, Pages 1743-1757
457.Waschbusch, R.J., W.R. Selbig, and R.T. Bannerman. 1999. Sources of phosphorus and street dirt from Two Urban Residential Basins in Madison, Wisconsin, 1994-95. USGS Water-Resources Investigation Report 99-4021
5U.S. EPA. Results of the Nationwide Urban Runoff Program. 1983. Volume I: Final Report. PB84-185552
6New York State Department of Environmental Conservation. August 2003. Stormwater Management Design Manual. Chapter 5 - Acceptable Stormwater Management Practices.
7Outfall monitoring data for Villa Park, Trout Brook East, Trout Brook West, Trout Brook Outlet, St. Anthony, Phalen Creek, Como 3, Como 7, and East Kittsendale


Event mean concentrations for total suspended solids

Event mean concentrations for total suspended solids.
Link to this table

Land cover/land use Range (mg/L) Recommended value (mg/L) Notes
Commercial 42-164 75 If applicable to models being used, adjust curve numbers/runoff coefficients when calculating loads
Industrial 70-170 93
  • If applicable to models being used, adjust curve numbers/runoff coefficients when calculating loads
Residential 42-101 73
High-density/Multi-family residential Calculate
  • Insufficient information to recommend a specific emc
Medium density residential Calculate
  • Insufficient information to recommend a specific emc
Low density residential Calculate
  • Insufficient information to recommend a specific emc
Freeways/transportation 50-90 87
Mixed 47-188 76 or calculate
  • 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
Open space 11-70 21
Conventional roof <20
Institutional 17-140 80
Forest/shrub/grassland 26-140 72 Sediment concentrations from forested areas vary widely with factors such as slope and forest condition. Concentrations may be very high, but the annual volume of runoff is typically much less than non-forested areas.
Open water and wetlands see Notes (next column)
  • If data exist, use the TSS concentration for the water body of interest
  • If data for a specific water body do not exist, use data from similar lakes in the area
Cropland (row crops) 50-160 Literature review was not adequate to recommend an emc
Pasture 75-150 84 Concentrations are a function of intensity of use.

This page was last edited on 2 February 2023, at 17:33.