Tappan Zee Bridge mid-channel

Tappan Zee mid-channel

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

86 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
10/16/2017<10Acceptable0.10.00.00.00.2
09/11/2017<10Acceptable0.00.00.00.00.0
08/14/2017<10Acceptable0.00.00.40.30.8
07/10/2017<10Acceptable0.00.00.02.22.2
06/12/2017<10Acceptable0.00.00.00.00.0
05/15/2017<10Acceptable0.00.11.70.01.8
04/04/201710Acceptable1.10.00.00.11.2
10/13/2016<10Acceptable0.10.00.00.00.1
09/14/2016<10Acceptable0.00.00.00.00.0
08/15/2016<10Acceptable0.00.10.10.20.4
07/13/2016<10Acceptable0.00.00.00.00.0
06/15/2016<10Acceptable0.00.00.00.00.0
05/20/2016<10Acceptable0.00.00.00.00.0
10/12/2015<10Acceptable0.00.00.00.10.1
09/11/2015<10Acceptable0.31.30.00.01.6
08/12/2015<10Acceptable0.01.00.00.01.0
07/08/2015<10Acceptable0.00.10.00.00.1
06/11/2015<10Acceptable0.00.00.20.20.4
05/12/2015<10Acceptable0.00.00.00.00.0
10/13/2014<10Acceptable0.00.00.40.00.4
09/08/2014<10Acceptable0.00.00.00.00.0
08/12/2014<10Acceptable0.00.00.00.00.0
07/08/2014<10Acceptable0.20.00.00.00.2
06/13/2014<10Acceptable1.40.00.10.01.5
05/13/2014<10Acceptable0.00.00.10.30.4
10/17/2013<10Acceptable0.00.00.00.00.0
09/19/201310Acceptable0.00.00.00.00.0
08/15/2013<10Acceptable0.00.00.70.41.1
07/18/201320Acceptable0.00.00.00.00.0
06/20/2013<10Acceptable0.00.00.30.20.5
05/30/2013<10Acceptable0.00.00.40.00.4
10/11/2012<10Acceptable0.00.10.00.00.1
09/11/2012<10Acceptable0.00.00.01.41.4
08/14/2012<10Acceptable0.00.00.00.00.0
07/17/2012<10Acceptable0.00.00.20.00.2
06/12/2012<10Acceptable0.00.00.00.00.0
05/16/2012<10Acceptable0.10.40.10.00.6
10/20/2011<10Acceptable0.00.10.00.00.1
09/15/201120Acceptable0.00.00.00.00.0
08/17/2011<10Acceptable0.00.00.03.43.4
08/15/2011<10Acceptable0.03.40.00.03.4
07/25/2011<10Acceptable0.00.00.00.00.0
07/22/2011<10Acceptable0.00.00.00.00.0
07/21/2011<10Acceptable0.00.00.00.10.1
07/18/2011<10Acceptable0.00.00.00.00.0
06/28/2011<10Acceptable0.00.00.00.00.0
05/17/201152Acceptable1.20.00.80.02.0
10/13/201010Acceptable0.00.10.30.00.4
09/12/2010<10Acceptable0.00.00.00.00.0
08/18/2010<10Acceptable0.00.00.20.30.5
07/22/2010<10Acceptable0.00.10.01.41.5
06/16/2010<10Acceptable0.00.00.00.00.0
05/22/201030Acceptable0.00.00.00.00.0
10/20/2009<10Acceptable0.00.00.00.00.0
09/15/2009<10Acceptable0.00.00.00.00.0
08/21/2009<10Acceptable0.00.00.00.00.0
07/29/2009<10Acceptable0.00.00.00.20.2
06/23/2009<10Acceptable0.00.00.60.51.1
06/06/2009<10Acceptable0.00.80.40.41.6
05/13/2009<10Acceptable0.00.00.00.00.0
10/21/200810Acceptable0.00.00.00.00.0
10/20/2008<10Acceptable0.00.00.00.00.0
10/19/2008<10Acceptable0.00.00.00.00.0
09/23/2008<10Acceptable0.00.00.00.00.0
09/07/200830Acceptable0.04.80.00.04.8
08/21/2008<10Acceptable0.00.00.00.00.0
07/15/2008<10Acceptable0.01.10.00.01.1
06/25/2008142Beach Advisory0.00.00.00.10.1
06/16/20086Acceptable0.00.01.70.01.7
05/20/200816Acceptable0.00.00.20.10.3
05/19/2008<10Acceptable0.00.20.10.91.2
05/16/2008<10Acceptable0.90.00.00.00.9
09/09/20071Acceptable0.00.00.00.00.0
09/06/2007<10Acceptable0.00.00.00.00.0
08/23/20071Acceptable0.00.01.30.11.4
08/16/2007<10Acceptable0.00.00.00.00.0
07/16/20073Acceptable0.00.00.00.00.0
07/11/20072Acceptable0.00.00.00.00.0
06/20/20071Acceptable0.10.30.00.00.4
06/18/20072Acceptable0.00.00.00.00.0
05/21/20074Acceptable0.00.00.20.00.2
04/25/200786Beach Advisory0.00.00.00.00.0
04/18/2007252Beach Advisory0.00.00.97.68.5
11/10/2006182Beach Advisory0.00.03.60.03.6
10/18/20061Acceptable0.01.10.00.01.1
09/26/20061Acceptable0.00.00.00.10.1

Entero Count (fecal indicator) and Rainfall Correlation

86 Samples taken

All Water Quality Parameters

86 Samples taken

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. It is the EPA preferred indicator for sewage contamination.

Quality [i] Temp (f)

Temperature

Hudson River water temperature changes seasonally. Surface water temperature can change on small scales in the river reflecting natural and human influences.

[i] Salinity

Salinity

Estuaries like the Hudson are where freshwaters in rivers meet the sea. Salinity tells us about the relative contribution of fresh and salt water within a particular region of the estuary. 

[i] Chlorophyll

Chlorophyll

A measure of the amount of microscopic algae present in the water. High chlorophyll counts can mean high levels of the nutrients phosphorus and nitrogen, and the threat, or presence, of algae blooms.

[i] Turbidity

Turbidity

Turbidity is a measure of the amount of fine particles suspended in the water. As turbidity rises, light penetration, a key factor for aquatic plants and algae, diminishes.

[i] Oxygen

Oxygen

Oxygen concentrations in the water are closely connected to biological activities. Surface waters are typically in equilibrium with the atmosphere such that the oxygen concentration near the surface is close to fully saturated (100%).

SortSortSortSortSortSortSortSort
10/16/2017<10Acceptable70.19.02.718.685.0
09/11/2017<10Acceptable718.83.916.488.9
08/14/2017<10Acceptable79.15.89.310.498.1
07/10/2017<10Acceptable78.23.73.812.9102.3
06/12/2017<10Acceptable71.21.33.518.3104.1
05/15/2017<10Acceptable58.40.63.222.597.1
04/04/201710Acceptablen/an/an/an/an/a
10/13/2016<10Acceptable669.75.43598
09/14/2016<10Acceptable80.98.820.4n/a153
08/15/2016<10Acceptable86.95.432.430173
07/13/2016<10Acceptable80.1614.59112
06/15/2016<10Acceptable73.74.16.219117
05/20/2016<10Acceptable64.92.77.2n/a120
10/12/2015<10Acceptable688.85.21096
09/11/2015<10Acceptable78.710.56.31790
08/12/2015<10Acceptable808.41810127
07/08/2015<10Acceptable78.71.49.521102
06/11/2015<10Acceptable76.32.77.73117
05/12/2015<10Acceptable65.93.93.225103
10/13/2014<10Acceptable64.79.60.12090
09/08/2014<10Acceptable77.881714106
08/12/2014<10Acceptable78.56.65.92585
07/08/2014<10Acceptable78.62.210.512105
06/13/2014<10Acceptable68.57.216.42196
05/13/2014<10Acceptable58.53.82n/a99
10/17/2013<10Acceptable66.310.62.62185
09/19/201310Acceptable715.94.1889
08/15/2013<10Acceptable76.84.310.69105
07/18/201320Acceptable832.96.21793
06/20/2013<10Acceptable69.70.63.61596
05/30/2013<10Acceptable65.110.74691
10/11/2012<10Acceptable65.95.54.52286
09/11/2012<10Acceptable76.18.19.41893
08/14/2012<10Acceptable82.18.85.85105
07/17/2012<10Acceptable82.48.718.87126
06/12/2012<10Acceptable72.323.82291
05/16/2012<10Acceptable63.90.5519108
10/20/2011<10Acceptable63.60.80.57491
09/15/201120Acceptable69.80.11.813585
08/17/2011<10Acceptable81.35.54.61495
08/15/2011<10Acceptablen/an/an/an/an/a
07/25/2011<10Acceptable82.93.4167n/a
07/22/2011<10Acceptable861.812.98n/a
07/21/2011<10Acceptablen/an/an/an/an/a
07/18/2011<10Acceptable823.74.916n/a
06/28/2011<10Acceptable78.31.75.1092
05/17/201152Acceptable59.92.82.714091
10/13/201010Acceptable65.40.26.32190
09/12/2010<10Acceptable72.58.16.11585
08/18/2010<10Acceptable79.97.732.144104
07/22/2010<10Acceptable81.88.72723132
06/16/2010<10Acceptable72.96.55.31785
05/22/201030Acceptable65.1566102
10/20/2009<10Acceptable57.55.12.61590
09/15/2009<10Acceptable74.66.33.72994
08/21/2009<10Acceptable81.16.55.72486
07/29/2009<10Acceptable78.92.33.21791
06/23/2009<10Acceptable70.70.41.32993
06/06/2009<10Acceptablen/an/an/an/an/a
05/13/2009<10Acceptable61.71.31.624100
10/21/200810Acceptable59.88.43.5691
10/20/2008<10Acceptable61.210.62.91092
10/19/2008<10Acceptable62.312.52.21687
09/23/2008<10Acceptable71.462692
09/07/200830Acceptablen/an/an/an/an/a
08/21/2008<10Acceptable7855.3995
07/15/2008<10Acceptable79.65.85.727104
06/25/2008142Beach Advisory75.166.21399
06/16/20086Acceptablen/an/an/an/an/a
05/20/200816Acceptable58.83.61.43494
05/19/2008<10Acceptable603.41.32994
05/16/2008<10Acceptablen/an/an/an/an/a
09/09/20071Acceptable77.711.47.11999
09/06/2007<10Acceptable75.7105.71195
08/23/20071Acceptable75.56.62.9486
08/16/2007<10Acceptable80.47.45.71395
07/16/20073Acceptable78.78.62.61789
07/11/20072Acceptable78.28.66.12097
06/20/20071Acceptablen/an/an/an/an/a
06/18/20072Acceptablen/an/an/an/an/a
05/21/20074Acceptable61.80.81.311593
04/25/200786Beach Advisory47.90.11.4202105
04/18/2007252Beach Advisory41.50.11.5125100
11/10/2006182Beach Advisory52.20.1013595
10/18/20061Acceptable62.75.6n/a1486
09/26/20061Acceptable68.952.4n/a99

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 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

About this location:

Tarrytown, NY
This deep water site at the Tappan Zee Bridge has boating, kayaking and fishing.

Agencies Responsible:

Westchester County Dept. of Health: 914-813-5000, Rockland County Dept. of Health: 845-364-2900 and NYSDEC Region 3: 914-428-2505

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