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100 Water Quality Modeling

Part 8. Water Quality and Biogeochemistry

  1. Steven C McCutcheon

Published Online: 15 APR 2006

DOI: 10.1002/0470848944.hsa104

Encyclopedia of Hydrological Sciences

Encyclopedia of Hydrological Sciences

How to Cite

McCutcheon, S. C. 2006. Water Quality Modeling. Encyclopedia of Hydrological Sciences. 8:100.

Author Information

  1. University of Georgia on assignment from the US EPA National Exposure Research Laboratory, Faculty of Engineering and Warnell School of Forest Resources, Athens, GA, US

Publication History

  1. Published Online: 15 APR 2006


Water quality forecasts are vital to determining limitations for point source waste loads and diffuse or nonpoint source loads required to meet water quality standards in streams, lakes, and estuaries. Only mechanistic water quality modeling is widely applicable for forecasting. Although surface water quality modeling has a sound interdisciplinary scientific basis, the use of these analysis tools are limited in regulatory and resource decision making by a lack of a professional consensus defining model application protocols. To analyze water quality problems, (i) the uses for a water body must be evaluated, (ii) models must be calibrated and tested to relate impaired water quality to the waste sources, (iii) a formal uncertainty analysis must define a margin of safety to protect human and ecological health, and (iv) when necessary, an economic analysis must be performed to determine if the designated uses are reasonably achievable.


  • water quality;
  • standards;
  • streams;
  • lakes;
  • estuaries;
  • watersheds;
  • point sources;
  • diffuse or nonpoint sources;
  • total maximum daily loads (TMDL);
  • waste load allocation;
  • forecasts;
  • hind casts;
  • mechanistic cause-and-effect modeling;
  • probabilistic modeling;
  • uncertainty analysis;
  • monte carlo analysis;
  • margin of safety;
  • calibration and statistical testing;
  • sensitivity testing: economic analysis;
  • newton's second law;
  • conservation of momentum, mass and energy;
  • fick's law;
  • advective-diffusion;
  • hydraulics;
  • hydrodynamics;
  • second law of thermodynamics;
  • geomorphology;
  • decision making