Development and Applications of Five New Water Quality Indices

Authors

  • PhD D. J. Schaeffer,

    Corresponding author
    1. Illinois Environmental Protection Agency and Sangamon State University, Springfield, Illinois, USA
    • Illinois Environmental Protection Agency 2200 Churchill Road Springfield Illinois 62 706, USA
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  • PhD K. G. Janardan

    Corresponding author
    1. Illinois Environmental Protection Agency and Sangamon State University, Springfield, Illinois, USA
    • Sangamon State University Shepherd Road Springfield Illinois 62708, USA
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Abstract

Two indices, P1 and I, employing ranked data and following the beta distribution, are described. These indices, which are true statistical measures of water quality, can be used with any set of parameters. Further, these indices correlate highly with biological and subjective-engineering assessments of water quality.

Three indices, employing raw data and based on the chi-square distribution, are described. Two of these, B1 and B2, do not have sufficient discrimination to serve as general measures of water quality, although they have use in specific circumstances. The index C has been found to be a measure of excessive variability (at a station), and can be used to quantitatively compare the (data) variability among stations.

The five indices described here are evaluated against a set of operational criteria which a mathematically sound index should meet.

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