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Estimations/Loading Factors

Literature Values

Literature values may be used to characterize source contributions and/or pollutant load removals or reductions. Literature values represent actual conditions; these values are typically based on data observed and measured in similar regions or watershed conditions. Application of literature values often involves broad assumptions about site conditions, such as uniform distribution, percent imperviousness, connectivity, and regular maintenance. Literature values may include generalized estimations for pollutant loading, BMP removal rates, or effluent concentrations for land uses or BMPs, for example. Area-based loading factors are common literature values used to estimate pollutant source contribution by land use type. These are regionally adjusted literature values that estimate pollutant discharge (i.e., mass or concentration) from a land area (e.g., acre) for a given time (e.g., annually). Land use-based loading factors are typically specific to land use type to account for the different amounts of pollutants generated within each land use. Values rely on local storm water monitoring data and may also vary from region to region.

References for literature values include, but are not limited to:

Land-based pollutant generation references

  • Bay Area Stormwater Management Agencies Association. 2017. Interim Accounting Methodology for TMDL Loads Reduced. Version 1.1. March 23, 2017. Download Methodology (1.1 MB)
  • Bicknell, B.R., J.C. Imhoff, J.L. Kittle, Jr., T.H. Jobes, and A.S. Donigian, Jr. (2001). Hydrological Simulation Program—FORTRAN, Version 12, User’s Manual. U.S. Environmental Protection Agency, National Exposure Research Laboratory, Athens, GA. Available Online
  • Burton, G.A., and Pitt, R.E., Stormwater Effects Handbook. Lewis Publishers, CRC Press, Boca Raton, FL, 2002. Available Online
  • Los Angeles County Department of Public Works. 2000. 1994-2000 Integrated Receiving Water Impacts Report. August 4, 2000. Available Online
  • National Cooperative Highway Research Program (NCHRP). 2014. Long-Term Performance and Life- Cycle Costs of Stormwater Best Management Practices. Report 792. Download Report (11.5MB)
  • National Stormwater Quality Database. Available Online
  • Stein, E.D., Teinfenthaler, L.L., and Schiff, K.C., 2007. “Sources, Patterns and Mechanisms of Storm Water Pollutant Loading from Watersheds and Land Uses of the Greater Los Angeles Area, California, USA.” Southern California Research Download Technical Report (1.9MB)
  • Tetra Tech, Inc. (2007). Watershed Hydrologic Modeling and Sediment and Nutrient Loading Estimation for the Lake Tahoe Total Maximum Daily Load. October 2005. Download Report (4.8MB)
  • Tetra Tech. 2009a. Los Angeles County Watershed Model Configuration and Calibration – Part I. Tetra Tech, Inc. Pasadena, CA, May 29, 2009. Download Report (4.8MB)
  • U.S. Environmental Protection Agency (US EPA), “Results of the Nationwide Urban Runoff Program, Volume I Final Report,” NTIS PB84-185552, Environmental Protection Agency, Washington, DC, December 1983. Download Report (1.8 MB)

BMP pollutant removal references

  • California Stormwater Quality Association (2003). Stormwater Best Management Practice Handbook: New Development and Redevelopment. Download Handbook (7MB)
  • City of Portland. 2006. Effectiveness Evaluation of Best Management Practices for Stormwater Management in Portland, Oregon. September 2006. Download Evaluation
  • International Stormwater BMP database. Available Online
  • County of San Diego, 2016. BMP Design Manual for Permanent Site Design. February 2016. Download Manual (2.7MB)
  • HDR. 2014. Nonstructural Non-Modeled Activity Pollutant Load Reduction Research – Addendum. November 5, 2014. Download Research (1.7MB)
  • Huber, W.C., L. Cannon, and M. Stouder, “BMP Modeling Concepts and Simulation”, EPA/600/R-06/033, U.S. Environmental Protection Agency, Cincinnati, OH, July 2006. Download Report (2.7 MB)
  • James, W., W.C. Huber, R.E. Pitt, R.E. Dickinson, L.A. Rosener, J.A. Aldrich, and W.R. James. (2002). SWMM4 User’s Manual (User’s Guide to the EPA Stormwater Management Model and to PCSWMM). University of Guelph and CHAI, Guelph, Ontario, Canada. Download Manual (1MB)
  • Pitt, R. Demonstration of Nonpoint Pollution Abatement through Improved Street Cleaning Practices. U.S. Environmental Protection Agency, Washington, DC, EPA/600/2-79/161, 1979. Available Online
  • 2NDNATURE, 2016c. Best Management Practice Rapid Assessment Methodology (BMP RAM). Technical Document v3.1. November 2016. Download Technical Document (1.6MB)

Scale: Varies

Considerations: Methodology may be used during planning phase and implementation phase of stormwater program.