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Water Quality

Since 2015 CURB has been monitoring and conducting research on sewage contamination in the Saw Mill and Hudson River with a host of partners and citizen scientist volunteers. Every year 16 Saw Mill River sites and 2 Hudson River sites are sampled biweekly May through October (the recreation season when people are more likely to be in the water) and tested for Enterococcus, a fecal indicator bacteria. The samples are analyzed at CURB’s lab and reported immediately to a list of 100+ Yonkers residents, municipal staff, and elected officials, and also key county, state, and federal contacts. The results are also posted on Riverkeeper’s website, along with rainfall data, which our data shows is a huge driver of fecal contamination levels. By tracking levels of fecal contamination, CURB is highlighting key issues facing water quality in Hudson River tributaries and leading the regional conversation for how to fix them. 

This program is a partnership of CURB, Riverkeeper, and the Yonkers Paddling and Rowing Club. It builds on Entero monitoring started in 2011 by the Yonkers Paddling and Rowing Club in partnership with the New York City Water Trail Association and The River Project and modeled on Riverkeeper’s ongoing monitoring projects. It also builds on previous water quality research done by Groundwork Hudson Valley, including a comprehensive study of the Saw Mill River watershed from 2008-2012.

In April 2017, with the support of the EPA, CURB joined forces with the Bronx River Alliance, the Hudson River Watershed Alliance, and Riverkeeper to form the Lower Hudson Urban Waters Collaborative, a new coalition linking four local watershed communities—Saw Mill River, Bronx River, Pocantico River, and Sparkill Creek—with the joint goal of galvanizing residents through educational workshops and accessible volunteer opportunities. CURB is the unifying force in this watershed research, bringing together local grassroots organizations to collaborate on monitoring efforts, data collection, and community education.


A primary local issue that CURB and our partners are working to solve is that Yonkers has a Combined Sewer System, which conveys municipal wastewater and stormwater in the same pipe. During rain events, instead of overwhelming the local wastewater treatment plants, the pipes overflow into waterways in what is known as Combined Sewer Overflow (CSO). CSOs in Yonkers alone contribute several hundred million gallons of wastewater into the Hudson River each year, bringing potentially dangerous contaminants into the local ecosystem and increasing health risks for people who use the river for recreation.

For additional information including data from the study see:

 Stakeholder Reports for the 2021 Sampling Season: