Skip to main content
U.S. flag

An official website of the United States government

Concentrations of Escherichia coli in streams in the Ohio River Watershed in Indiana, May—August 2000

October 1, 2002

Water samples collected from 40 stream sites in the Ohio River Watershed in Indiana from May through August 2000 were analyzed for concentrations of Escherichia coli (E. coli) bacteria. Each site was sampled five times in a 30-day period. Concentrations of E. coli in 72 of the 200 samples exceeded the State of Indiana single-sample standard of 235 colonies per 100 milliliters for waters used for recreation.

A five-sample geometric mean of concentrations was computed for each site. Concentrations in samples from 24 of the 40 sites exceeded the State of Indiana standard for a five-sample geometric mean of 125 colonies per 100 milliliters for waters used for recreation. Samples collected from 34 sites had E. coli concentrations that exceeded either or both the single-sample standard and the five-sample geometric mean standard.

Five of the 40 sampling sites were at or near U.S. Geological Survey streamflowgaging stations. On the basis of records from these stations, 16 percent of the samples from these sites were collected at streamflows above the median daily mean discharge for each station.

E. coli concentrations and turbidity measurements collected during 2000 were analyzed in concert with E. coli concentration and turbidity data collected in 1999 at streams within the Kankakee and Lower Wabash River Watersheds in Indiana and in 1998 at streams within the Upper Wabash River Watershed in Indiana. These data were grouped together to investigate the relation between concentrations of bacteria and turbidity. The resulting analysis indicated a statistically significant correlation between concentrations of E. coli and turbidity.

Citation Information

Publication Year 2002
Title Concentrations of Escherichia coli in streams in the Ohio River Watershed in Indiana, May—August 2000
DOI 10.3133/wri024064
Authors Cheryl A. Silcox, Bret A. Robinson, Timothy C. Willoughby
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Water-Resources Investigations Report
Series Number 2002–4064
Index ID wri024064
Record Source USGS Publications Warehouse
USGS Organization Indiana Water Science Center