Riverkeeper > Water Quality > Hudson River Data

Hudson River Data

Riverkeeper Testing Sites

Water Quality Conditions by Location

Recent Samples Historical Statistics
Site Name Sample Date [i] Entero Count

Entero Count

Enterococcus (“Entero”) is a fecal indicating bacterium that lives in the intestines of humans and other warm-blooded animals.

[i] 4 Days Total Rain (in)

4 Days Total Rain (in)

The combined rainfall for the day of sampling, prior day, two days prior and three days prior. More than 1/4 inch is considered a “wet weather sample.”

[i] Number of Samples

Number of Samples

Total number of samples included in these calculations.

[i] Geometric
Mean

Geometric Mean

A measure of central tendency (a weighted average) used by NYS DEC and the US EPA to assess water quality. The geometric mean is defined as the nth root (where n is the number of samples) of the product of the Enterococcus measurements. A geometric mean over 30 fails the EPA criteria for safe primary contact.

[i] Maximum

Maximum

The highest Enterococcus count we have recorded at this site (“>” indicates an unknown number greater than this number and reflects the upper limit of our scoring ability for this sample).

[i] Minimum

Minimum

The lowest Enterococcus count we have recorded at this site (“<” indicates an unknown number less than this number and reflects the lower limit of our scoring ability for this sample).

Individual Entero Counts by Site

Note: multiple counts of the same value will overlap and appear as one dot.

Water Quality*

Acceptable (0–60) Beach Advisory (61+)

*Single sample thresholds;
Enterococcus count per 100mL

Prior Four Day Rainfall
(in inches)

Dry Weather (0–0.25) Wet Weather (0.25+)

Geometric Mean*

Acceptable (0–30) Unacceptable (31+)

*Weighted average of multiple
samples; Enterococcus count
per 100mL

Enterococcus is an EPA-approved fecal contamination indicator.

Samples taken by Riverkeeper, Lamont-Doherty Earth Observatory and CUNY Queens College staff, and processed on the Riverkeeper vessel, according to the 2014 Quality Assurance Project Plan.

Rainfall data comes from wunderground.com. Wet weather is a common trigger of fecal contamination.

What do the Numbers Mean?

Water Quality scoring is based on the 2012 Recreational Water Quality Criteria from the US Environmental Protection Agency (EPA) for safe swimming. Learn More





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