Water Quality > Tributary and Waterfront Data > Saw Mill River > New Castle- Tertia Brook tributary

New Castle- Tertia Brook tributary

Physical/Chemical Data

Physical, chemical and biological properties of the surface water that are measured continuously while the patrol boat is underway.

Entero Count (fecal indicator) and Rainfall

27 Samples taken

Sample Date [i] Enterococcus Count

Entero Count

Enterococcus (“Entero”) is a fecal indicating bacterium that lives in the intestines of humans and other warm-blooded animals. It is the EPA preferred indicator for sewage contamination.

QualityRain, day of (in)Prior Day2 Days Prior3 Days Prior Rain4 Days Total Rain
SortSortSortSortSortSortSortSort
10/12/20171254Beach Advisory0.10.00.00.20.3
09/28/201785Beach Advisory0.00.00.00.00.0
09/14/201731Acceptable0.00.00.00.00.0
08/03/2017933Beach Advisory0.00.60.00.00.6
07/20/2017166Beach Advisory0.00.00.00.00.0
06/22/2017638Beach Advisory0.00.00.00.90.9
06/08/201775Beach Advisory0.00.00.20.10.3
05/11/201798Beach Advisory0.00.00.00.00.0
10/27/2016160Beach Advisory0.00.00.00.00.0
10/13/2016310Beach Advisory0.00.00.00.00.0
09/29/201611200Beach Advisory0.00.00.40.00.4
09/15/201630Acceptable0.00.00.00.00.0
09/01/2016280Beach Advisory0.00.00.00.00.0
08/18/2016690Beach Advisory0.00.00.40.00.4
08/04/2016180Beach Advisory0.00.00.00.00.0
07/14/20161550Beach Advisory0.00.00.00.00.0
06/30/20166130Beach Advisory0.00.00.30.30.7
06/16/2016420Beach Advisory0.00.00.00.00.0
06/02/2016420Beach Advisory0.00.00.00.60.6
05/19/201650Acceptable0.00.00.00.00.0
10/08/2015464Beach Advisory0.00.00.00.00.0
09/24/2015110Beach Advisory0.00.00.00.00.0
09/10/20158664Beach Advisory0.20.00.00.00.2
08/27/2015638Beach Advisory0.00.00.00.00.0
08/13/201514136Beach Advisory0.00.00.60.00.6
07/30/2015959Beach Advisory0.00.00.00.00.0
07/16/20153654Beach Advisory0.00.00.40.00.4

Entero Count (fecal indicator) and Rainfall Correlation

27 Samples taken

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+)

Enterococcus is an EPA-approved fecal contamination indicator.

Samples taken by citizen scientists and processed at laboratories that aren't directly affiliated with Riverkeeper, using methods and study designs that are consistent with Riverkeeper's Hudson River and Citizen Testing programs.

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

About this location:

The Tertia Brook is the first named tributary to enter the Saw Mill River. This site is located where the Tertia Brook enters the parking lot of the Chappaqua Public Library. Upstream of here, the brook flows from its headwaters through residential areas.

Agencies Responsible:

Westchester County Dept. of Health: 914-813-5000; NYSDEC Region 3: 914-428-2505

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