Information: This page was updated October 31, 2019. Read table caption below.


Event mean concentrations for total phosphorus. This table was updated October 31, 2019. We retained data from the previous table, but we recommend using the median values from a literature review (3rd column). To see supporting information used to derive this table, link here.
Link to this table

Land cover/land use Range (mg/L) Median from literature review (mg/L)1 Recommended value (mg/L)1 Notes
Commercial 0.20 - 0.34 0.17 0.20 If applicable to models being used, adjust curve numbers/runoff coefficients when calculating loads
Industrial 0.23 - 0.55 0.235 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 0.36 0.325 Concentrations vary widely depending on local conditions
High-density/Multi-family residential 0.28 - 0.40 0.28 Calculate
  • Insufficient information to recommend a specific emc
  • Concentrations vary widely depending on local conditions
Medium density residential 0.18 - 0.40 0.18 Calculate *Insufficient information to recommend a specific emc
  • Concentrations vary widely depending on local conditions
Low density residential 0.24 - 0.40 0.24 Calculate
  • Insufficient information to recommend a specific emc
  • Concentrations vary widely depending on local conditions
Freeways/transportation 0.25 - 0.45 0.35 0.28
  • Concentrations vary
0.25
Mixed 0.25 - 0.45 0.29
Parks and recreation
Open space 0.12 - 0.31 0.13 0.19
Conventional roof 0.05 - 0.20 0.09
Public/semi public (institutional) 0.18 - 0.40 0.26
Cropland
Forest/shrub/grassland
Open water
Wetlands
Farmsteads
Forest 0.05 - 0.25 0.25