RiverWatch
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 2024, only three sample sites didn’t meet the swimming standard (35 cfu/100mL), those sites including the Washington Street Bridge, Cornhill Lane, and the Union Street Bridge. Unfortunately, the geometric mean of fecal coliform exceeded the shellfish standard at all marine sites.
TEMPERATURE
Measuring temperature is a part of almost all of our monitoring efforts. 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 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 0.0567°C annually or 1.13°C from 2004-2024
Download the 2023-2024 Annual Citizen Science Monitoring Report here.
