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              Quarterly Progress Report August 2004
North Fork Kaskaskia River Watershed
Limno-Tech, Inc. Page 26
Methods of data analysis
The water quality data were analyzed to confirm the cause of impairment for each
waterbody and, in combination with the watershed characterization data, were assessed to
confirm the sufficiency of the data to support the listing decision and the sources of
impairment that are included on the draft 2004 303(d) list.
Analysis methods including computing summary statistics, comparing the data to water
quality criteria, evaluating trends and correlations, and using graphical analysis to discern
relationships in the data.
CONFIRMATION OF CAUSES AND SOURCES OF IMPAIRMENT
Water quality data were evaluated to confirm the cause of impairment for each waterbody
in the North Fork Kaskaskia River watershed, and in combination with the watershed
characterization data, the sufficiency of the data were assessed to support the listing
decision and the sources of impairment that are included on the 2004 303(d) list.
Table 11 lists the impaired waterbodies, the applicable water quality criteria, and the
number of samples exceeding the criteria. These data are discussed by waterbody in the
following sections. This section presents an assessment of the sufficiency of the data to
support the 303(d) listings and identifies suspected or known sources.