Validation approaches for field-, basin-, and regional-scale water quality models

David J. Mulla, Thomas M. Addiscott

Research output: Chapter in Book/Report/Conference proceedingChapter

5 Scopus citations


Environmental issues such as global warming, hypoxia, and non-point source pollution of rivers and aquifers occur at scales which include the entire earth, the Gulf of Mexico, the Baltic Sea, the Mississippi and Amazon River basins, as well as smaller regions which cover states, provinces, and counties. The increasing availability of data layers at these scales through remote sensing and Geographic Information Systems (GIS) makes it possible to model transport processes at scales far removed from the traditional plot and field scales at which most transport models in soil physics were developed. This paper reviews and synthesizes the general approaches and concepts governing the use of water and solute transport models over a wide range of scales. Topics discussed include model selection, criteria for model calibration and validation, sources of error in modeling, non-linearity, spatial variability, non-uniqueness, and scale-transition techniques. The paper concludes that rigorous validation of models at the scale of large regions, basins, or continents is difficult for a variety of reasons. This does not preclude the value of modeling transport processes over large regions. If proper procedures are followed for model selection and calibration, then there can still be great value in using the model to investigate various scenarios, which would be impossible to study experimentally.

Original languageEnglish (US)
Title of host publicationAssessment of Non-Point Source Pollution in the Vadose Zone, 1999
EditorsDennis L. Corwin, Keith Loague, Timothy R. Ellsworth
Place of PublicationWashington, DC
PublisherAmer. Geophys. Union
Number of pages16
ISBN (Electronic)9781118664698
ISBN (Print)9780875900919
StatePublished - 1999

Publication series

NameGeophysical Monograph Series
ISSN (Print)0065-8448
ISSN (Electronic)2328-8779


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