2024 Bacteria Monitoring Success: Swimmable Waters and Areas of Concern
October 31, 2024
OARS River Log | By Ben Wetherill, OARS’ Water Quality Scientist | Published October 31 2024
We had a very successful bacteria monitoring season in 2024. Fifteen volunteers helped us collect water samples from 12 different sites on the Sudbury, Assabet, and Concord rivers from May to September. In general, our 2024 bacteria monitoring highlighted the same sites of concern as in previous years. The Ashland, Lowell, and Maynard sites (SUD-236, CND-009, ABT-077) all had seasonal geometric means above the swimming threshold of 126 CFU/100 ml. These three sites have exceeded the threshold almost every year. Our volunteers have been helping us conduct focused source-tracking studies in these three sites. Reports for the Lowell and Maynard studies were published in previous years, and a report for Ashland will be published later this year. The upper Concord River and lower Sudbury River sites (CND-093, SUD-144) continued to have very low bacteria levels and mostly swimmable conditions. The Concord River (CND-093) site was swimmable 100% of the time. The Sudbury Landing site (SUD-144) was a new site moved slightly upstream, closer to the populated Saxonville area, but results there were similar to the previous downstream sites with very low bacteria levels and swimmable conditions for all but one of the sampling events. This year, we also added a site in West Concord (ABT-033), and we were pleased to see that bacteria levels were low and conditions were mostly swimmable at this site, too. It is noteworthy that all the sites within the Wild & Scenic designated sections of our rivers in the lower Assabet, Sudbury, and upper Concord have consistently been mostly or completely swimmable for all of our sampling years.
Bacteria pollution is often a local issue. We find that it does not travel too far downstream before it is diluted or neutralized. So, resolving bacterial pollution is often achievable at the town level. We can use your help sharing this information with your town of residence. Feel free to forward it as is, and we are happy to provide the raw data if requested.