We currently have two water quality monitoring programs, although collecting water quality data is also an essential part of our other citizen science projects as well.

RiverWatch sites


RiverWatch is a volunteer-driven effort that monitors local waters for compliance with both swimming and shellfishing water quality standards. Since 1994, we have monitored bacteria and other water quality indicators like temperature, dissolved oxygen, salinity, and conductivity at ten sites in the North and South Rivers every other week from June through August.

Since we have started sampling, the percent of bacterial samples that have exceeded the swimming standard each summer has decreased, from 22-24% in the 90s and 2000s to 15% in the 2010s and 2020s. This is due to a reduction in stormwater pollution as well as increased sewering along the South River that reduced wastewater pollution.

In 2017 we started testing enterococcus bacteria at all ten RiverWatch sites. In 2022, the geometric mean of all the samples met the swimming standard (35 cfu/100mL) at all sites except the Washington Street Bridge and Willow Street/Keville Footbridge. The geometric mean of fecal coliform did not exceed the shellfish standard at any marine sites except Julian Street, which is outside the conditionally approved shellfishing area.


Measuring temperature is a part of almost every monitoring effort we do. We were curious whether we could detect any increases in temperature due to climate change in our RiverWatch temperature record, which is the most reliable and consistent. There were no trends looking at all the data pooled together over time, nor looking at each site’s data for an entire summer over time. However, we did find a significant trend in the August water temperature at the Washington St Bridge site on the North River in Pembroke. and Hanover. We conduct these surveys to track new and existing invasive species that impact intertidal and subtidal ecology by occupying niches belonging to native species. August water temperatures at Washington Street Bridge have increased an average of 0.16°C annually or 2.8°C since 2004.

Current water quality data can be found by using the search bar at the top of our website. Search  RiverWatch for the most recent data on water quality.

Download the 2022 Annual Citizen Science Monitoring Report here.

North River Headwaters

We have been funded by MassDEP to use bacterial source tracking to locate potential stormwater and wastewater pollution in the headwaters of the North River, including the Indian Head River, Drinkwater River, and French’s Stream. This project will require both regularly scheduled sampling as well as being on-call for wet weather sampling.

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