Water Quality
Water Quality > Tributary and Waterfront Data > Saw Mill River > Yonkers- Saw Mill River, Van der Donck Park

Yonkers- Saw Mill River, Van der Donck Park

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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

161 Samples taken

Sample Date [i] Enterococcus Count
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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 Rain, day of (in) Prior Day 2 Days Prior 3 Days Prior Rain 4 Days Total Rain
Sort Sort Sort Sort Sort Sort Sort Sort
07/25/2024 3441 Beach Advisory 0.0 0.1 0.3 0.0 0.3
07/11/2024 337 Beach Advisory 0.0 0.0 0.0 0.0 0.0
06/27/2024 9208 Beach Advisory 0.4 0.0 0.0 0.0 0.4
06/13/2024 359 Beach Advisory 0.0 0.0 0.0 0.0 0.0
05/30/2024 12997 Beach Advisory 1.2 0.0 0.2 0.3 1.6
05/16/2024 4106 Beach Advisory 0.0 0.2 0.0 0.0 0.3
05/02/2024 10 Acceptable 0.0 0.1 0.0 0.0 0.1
10/19/2023 428 Beach Advisory 0.0 0.0 0.0 0.0 0.0
10/05/2023 410 Beach Advisory 0.0 0.0 0.0 0.0 0.0
09/21/2023 465 Beach Advisory 0.0 0.0 0.5 0.8 1.3
09/07/2023 295 Beach Advisory 0.0 0.0 0.0 0.0 0.0
08/24/2023 441 Beach Advisory 0.0 0.0 0.0 0.0 0.0
08/10/2023 209 Beach Advisory 0.0 0.0 0.2 0.7 0.9
07/27/2023 620 Beach Advisory 0.0 0.0 0.7 0.0 0.7
07/13/2023 1780 Beach Advisory 0.0 0.0 0.0 0.0 0.0
06/29/2023 650 Beach Advisory 0.0 0.0 0.1 0.5 0.6
06/15/2023 4611 Beach Advisory 0.0 0.2 0.0 0.1 0.3
06/01/2023 134 Beach Advisory 0.0 0.0 0.0 0.0 0.0
05/18/2023 85 Beach Advisory 0.0 0.0 0.0 0.0 0.0
05/04/2023 183 Beach Advisory 0.1 0.0 0.0 0.0 0.1
10/27/2022 323 Beach Advisory 0.0 0.0 0.1 0.5 0.5
10/13/2022 383 Beach Advisory 0.0 0.0 0.0 0.0 0.0
09/29/2022 144 Beach Advisory 0.0 0.0 0.0 0.0 0.0
09/15/2022 311 Beach Advisory 0.0 0.0 0.6 0.2 0.8
09/01/2022 581 Beach Advisory 0.0 0.0 0.1 0.0 0.1
08/18/2022 211 Beach Advisory 0.0 0.0 0.0 0.0 0.0
08/04/2022 173 Beach Advisory 0.0 0.0 0.0 0.2 0.2
07/21/2022 738 Beach Advisory 0.0 0.0 0.0 4.8 4.8
10/21/2021 213 Beach Advisory 0.0 0.0 0.0 0.0 0.0
10/07/2021 345 Beach Advisory 0.0 0.0 0.2 0.5 0.7
09/23/2021 410 Beach Advisory 0.0 0.0 0.0 0.0 0.0
09/09/2021 19863 Beach Advisory 0.4 0.0 0.0 0.0 0.4
08/19/2021 6131 Beach Advisory 0.2 0.0 0.0 0.0 0.2
08/05/2021 457 Beach Advisory 0.0 0.0 0.0 0.0 0.0
07/22/2021 771 Beach Advisory 0.0 0.0 0.0 0.0 0.1
07/08/2021 448 Beach Advisory 0.0 0.0 0.3 0.0 0.3
06/24/2021 31 Acceptable 0.0 0.0 0.3 0.0 0.3
06/10/2021 457 Beach Advisory 0.0 0.0 0.8 0.3 1.1
05/27/2021 8664 Beach Advisory 0.1 0.0 0.0 0.0 0.1
05/13/2021 85 Beach Advisory 0.0 0.0 0.0 0.1 0.1
10/24/2019 189 Beach Advisory 0.0 0.0 0.5 0.0 0.5
10/10/2019 1178 Beach Advisory 0.0 1.0 0.1 0.8 1.8
09/26/2019 175 Beach Advisory 0.0 0.0 0.0 0.0 0.1
09/12/2019 218 Beach Advisory 0.0 0.0 0.0 0.0 0.0
08/15/2019 563 Beach Advisory 0.0 0.0 0.0 0.0 0.0
08/01/2019 5475 Beach Advisory 0.0 1.0 0.0 0.0 1.0
07/02/2019 161 Beach Advisory 0.0 0.0 0.0 0.0 0.0
06/20/2019 563 Beach Advisory 0.0 0.0 0.3 0.0 0.4
06/06/2019 201 Beach Advisory 0.0 0.0 0.0 0.0 0.0
05/23/2019 2224 Beach Advisory 0.1 0.0 0.0 0.2 0.3
05/09/2019 158 Beach Advisory 0.0 0.0 0.1 0.0 0.1
10/18/2018 75 Beach Advisory 0.0 0.0 0.1 0.1 0.1
10/04/2018 1835 Beach Advisory 0.0 0.0 0.7 0.0 0.7
10/04/2018 1835 Beach Advisory 0.0 0.0 0.8 0.0 0.8
09/20/2018 131 Beach Advisory 0.0 0.0 1.2 0.0 1.2
09/20/2018 131 Beach Advisory 0.0 0.0 1.1 0.0 1.1
09/06/2018 30 Acceptable 0.4 0.0 0.0 0.0 0.4
09/06/2018 30 Acceptable 0.0 0.0 0.0 0.0 0.0
08/23/2018 670 Beach Advisory 0.0 1.0 0.1 0.0 1.1
08/23/2018 670 Beach Advisory 0.0 1.0 0.0 0.0 1.0
08/09/2018 2064 Beach Advisory 0.6 0.0 0.1 0.0 0.7
08/09/2018 2064 Beach Advisory 0.4 0.0 0.2 0.0 0.6
08/02/2018 990 Beach Advisory 0.5 0.0 0.0 0.4 0.9
07/26/2018 3784 Beach Advisory 0.1 1.0 0.0 0.3 1.4
07/26/2018 537 Beach Advisory 0.0 1.0 0.0 0.2 1.2
07/19/2018 10 Acceptable 0.0 0.0 2.2 0.0 2.2
07/12/2018 231 Beach Advisory 0.0 0.0 0.0 0.0 0.0
07/05/2018 52 Acceptable 0.0 0.0 0.0 0.0 0.0
06/28/2018 7556 Beach Advisory 1.4 0.0 0.0 0.0 1.4
06/14/2018 75 Beach Advisory 0.0 0.0 0.0 0.0 0.0
06/14/2018 75 Beach Advisory 0.0 0.0 0.0 0.0 0.0
05/31/2018 221 Beach Advisory 0.0 0.0 0.0 0.0 0.0
05/17/2018 8164 Beach Advisory 0.2 1.0 0.4 0.0 1.7
10/26/2017 563 Beach Advisory 0.0 0.0 0.2 0.0 0.2
10/12/2017 616 Beach Advisory 0.2 0.0 0.0 0.2 0.4
09/28/2017 41 Acceptable 0.0 0.0 0.0 0.0 0.0
09/14/2017 183 Beach Advisory 0.0 0.0 0.0 0.0 0.0
08/31/2017 31 Acceptable 0.0 0.0 0.2 0.0 0.2
08/03/2017 373 Beach Advisory 0.0 0.0 0.0 0.0 0.0
07/06/2017 97 Beach Advisory 0.0 0.0 0.1 0.0 0.1
06/22/2017 41 Acceptable 0.0 0.0 0.0 0.0 0.0
06/15/2017 109 Beach Advisory 0.0 0.0 0.0 0.0 0.0
06/08/2017 185 Beach Advisory 0.0 0.0 0.0 0.0 0.0
05/25/2017 2755 Beach Advisory 0.4 0.0 0.0 0.5 0.9
05/11/2017 31 Acceptable 0.0 0.0 0.0 0.0 0.0
10/27/2016 270 Beach Advisory 0.1 0.0 0.0 0.1 0.1
10/13/2016 50 Acceptable 0.0 0.0 0.0 0.0 0.0
09/29/2016 30 Acceptable 0.0 0.0 0.3 0.0 0.3
09/22/2016 85 Beach Advisory 0.0 0.0 0.0 0.5 0.5
09/15/2016 50 Acceptable 0.0 0.0 0.0 0.0 0.0
09/08/2016 52 Acceptable 0.0 0.0 0.0 0.0 0.0
09/01/2016 960 Beach Advisory 0.1 0.0 0.0 0.0 0.1
08/25/2016 355 Beach Advisory 0.0 0.0 0.0 0.0 0.0
08/18/2016 510 Beach Advisory 0.0 0.0 0.9 0.0 0.9
08/11/2016 457 Beach Advisory 0.0 0.0 0.0 0.0 0.0
08/04/2016 280 Beach Advisory 0.0 0.0 0.0 0.0 0.0
07/28/2016 52 Acceptable 0.0 0.0 0.0 0.2 0.2
07/21/2016 73 Beach Advisory 0.0 0.0 0.0 0.1 0.1
07/14/2016 1480 Beach Advisory 0.2 0.0 0.0 0.0 0.2
07/07/2016 216 Beach Advisory 0.1 0.0 0.7 0.2 0.9
06/30/2016 320 Beach Advisory 0.0 0.0 0.5 0.3 0.7
06/23/2016 120 Beach Advisory 0.0 0.0 0.0 0.0 0.0
06/16/2016 570 Beach Advisory 0.1 0.0 0.0 0.0 0.1
06/02/2016 320 Beach Advisory 0.0 0.0 0.0 1.1 1.1
05/26/2016 488 Beach Advisory 0.0 0.0 0.0 0.0 0.0
05/19/2016 360 Beach Advisory 0.0 0.0 0.0 0.0 0.0
10/08/2015 987 Beach Advisory 0.0 0.0 0.0 0.0 0.0
10/01/2015 11199 Beach Advisory 0.0 1.0 0.0 0.0 1.0
09/24/2015 275 Beach Advisory 0.0 0.0 0.0 0.0 0.0
09/17/2015 556 Beach Advisory 0.0 0.0 0.0 0.0 0.0
09/03/2015 203 Beach Advisory 0.0 0.0 0.0 0.0 0.0
08/27/2015 323 Beach Advisory 0.0 0.0 0.0 0.0 0.0
08/20/2015 364 Beach Advisory 0.0 0.0 0.0 0.0 0.0
08/13/2015 573 Beach Advisory 0.0 0.0 0.7 0.0 0.7
08/06/2015 209 Beach Advisory 0.0 0.0 0.1 0.0 0.1
07/30/2015 588 Beach Advisory 0.0 0.0 0.0 0.0 0.0
07/23/2015 173 Beach Advisory 0.0 0.0 0.1 0.0 0.1
07/16/2015 301 Beach Advisory 0.0 0.0 1.5 0.0 1.5
07/09/2015 3255 Beach Advisory 0.0 0.0 0.0 0.0 0.0
07/01/2015 11199 Beach Advisory 0.5 0.0 0.0 0.3 0.9
06/25/2015 355 Beach Advisory 0.0 0.0 0.0 0.0 0.0
06/18/2015 528 Beach Advisory 0.0 0.0 0.1 0.2 0.4
06/11/2015 546 Beach Advisory 0.0 0.0 0.0 0.0 0.0
06/04/2015 816 Beach Advisory 0.0 0.0 0.0 0.2 0.2
05/28/2015 3873 Beach Advisory 0.0 0.0 0.0 0.0 0.0
05/21/2015 650 Beach Advisory 0.0 0.0 0.1 0.0 0.1
10/02/2014 272 Beach Advisory 0.0 0.0 0.0 0.0 0.0
09/25/2014 1145 Beach Advisory 0.3 0.0 0.0 0.0 0.3
09/18/2014 160 Beach Advisory 0.0 0.0 0.4 0.0 0.4
09/11/2014 211 Beach Advisory 0.0 0.0 0.0 0.0 0.0
09/04/2014 241 Beach Advisory 0.0 0.0 0.0 0.0 0.0
08/28/2014 331 Beach Advisory 0.0 0.0 0.0 0.0 0.0
08/14/2014 2489 Beach Advisory 0.0 1.0 0.2 0.0 1.2
08/07/2014 166 Beach Advisory 0.0 0.0 0.0 0.0 0.0
07/31/2014 448 Beach Advisory 0.0 0.0 0.0 0.2 0.2
07/24/2014 488 Beach Advisory 0.0 0.0 0.0 0.0 0.0
07/17/2014 1071 Beach Advisory 0.0 0.0 1.3 0.5 1.8
07/10/2014 450 Beach Advisory 0.0 0.0 0.4 0.0 0.4
07/02/2014 295 Beach Advisory 1.0 0.0 0.0 0.0 1.0
06/26/2014 4786 Beach Advisory 0.1 0.0 0.0 0.0 0.1
06/19/2014 2595 Beach Advisory 0.2 0.0 0.0 0.0 0.2
06/12/2014 613 Beach Advisory 0.1 0.0 0.0 1.6 1.7
05/29/2014 443 Beach Advisory 0.0 0.0 0.0 0.0 0.0
05/22/2014 4352 Beach Advisory 0.2 0.0 0.0 0.0 0.2
10/03/2013 332 Beach Advisory 0.0 0.0 0.0 0.0 0.0
09/26/2013 216 Beach Advisory 0.0 0.0 0.0 0.0 0.0
09/19/2013 203 Beach Advisory 0.0 0.0 0.0 0.0 0.0
09/12/2013 426 Beach Advisory 1.6 0.0 0.0 0.0 1.6
08/29/2013 689 Beach Advisory 0.0 0.0 0.0 0.0 0.1
08/22/2013 521 Beach Advisory 0.3 0.0 0.0 0.0 0.3
08/15/2013 820 Beach Advisory 0.0 0.0 0.9 0.1 0.9
08/08/2013 776 Beach Advisory 0.5 0.0 0.0 0.0 0.5
08/01/2013 480 Beach Advisory 0.7 0.0 0.0 0.0 0.7
07/25/2013 2300 Beach Advisory 0.0 0.0 0.3 0.1 0.4
07/18/2013 241 Beach Advisory 0.0 0.0 0.0 0.0 0.0
07/02/2013 19863 Beach Advisory 0.1 1.0 0.0 0.0 1.1
06/27/2013 216 Beach Advisory 0.2 0.0 0.0 0.0 0.2
06/20/2013 226 Beach Advisory 0.0 0.0 0.2 0.0 0.2
06/13/2013 573 Beach Advisory 1.3 0.0 0.1 1.4 2.7
06/06/2013 437 Beach Advisory 0.1 0.0 0.0 0.9 1.0
05/23/2013 187 Beach Advisory 1.8 0.0 0.0 0.0 1.8

Entero Count (fecal indicator) and Rainfall Correlation

161 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:

This site is located in downtown Yonkers a few blocks from the Hudson River, in the section of the Saw Mill River that was daylighted in 2011. The area is now a park and it is used by Groundwork Hudson Valley for educational programs. Partners: Groundwork Hudson Valley (sponsor), Sarah Lawrence College Center for the Urban River at Beczak (lab analysis); Site Coordinators: Jerry Blackstone and Robert Hothan

Agencies Responsible:

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

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