Conventional, Nutrient and Bacteria charts illustrate results from
monthly stream and river monitoring during the current year. Water samples
collected under both baseflow and wet weather/storm flow conditions are
included in these charts.
Where applicable, data are compared with water quality criteria established by
the Washington State Department of Ecology (WDOE) in the Washington
Administrative Code [WAC] 173-201A. For more information about these criteria,
visit WDOE's Web site.
For most sites data collection began in the 1970s. The period of record for each site is
shown on the
Stream and Rivers Ambient Monitoring Sites Table. Historical data for
this site are represented by box plots (see explanation below).
Box Plots Explained
We are using boxplots to display monthly historical data. Box plots, or box and
whisker plots, succinctly summarize the median, upper and lower quartiles, and
minimum and maximum values.
Interpreting a Boxplot
The box contains the middle 50% of the data. The upper edge (hinge) of the box
indicates the 75th percentile of the data set, the lower hinge indicates the
25th percentile. The difference between the values of the hinges is called the
interquartile range. The line in the box indicates the median value of the data
set. The ends of the vertical lines (whiskers) extend to 1.5 times the
interquartile range. Values that lie out side of the whiskers are termed
outliers. Outliers can be viewed or hidden by checking/unchecking the outlier box.
For more information about archived data , please contact Debra Bouchard at
debra.bouchard@kingcounty.gov.
