The show must go on as they say! Our steadfast volunteers began our water quality monitoring this season on June 10, 2020. The RiverWatch program is going as planned, with 10 spots tested for enterococcus and 5 spots tested for fecal coliform, two important bacteria measurements for water quality. This data is collected and compared to state standards in order to determine that week’s water quality and identify any areas of interest. We use the state standards for swimming and shellfishing, as those are two popular activities in our area that depend on bacteria levels.
Testing Results from 7-27-20
On July 28th, 2020, we completed another round of our RiverWatch Water Quality Monitoring Program. Ten locations were tested for enterococcus, while five of those locations were also tested for fecal coliform. Enterococcus and fecal coliform are two bacteria that are often used to determine water quality. This data is collected and compared to state standards in order to determine that week’s water quality and identify any areas of interest or concern. We use the state standards for swimming and shellfishing, as those are two popular activities in our area that depend on bacteria levels.
This past week, out of the ten locations tested for enterococcus, one was over the state standard for swimming. The state threshold is 104 cfu per 100 mL, and the Washington Street Bridge site exceeded that with a level of 130 cfu per 100 mL. At the five locations tested for fecal coliform, two were over the state standard for shellfishing. The state standard is 14 cfu per 100 mL, and North River Marine and Julian Street Bridge were both over the threshold, with fecal coliform levels of 28 and 21 cfu per 100 mL, respectively. None of the five locations tested for fecal coliform were above the state standard for swimming (400 cfu per 100 mL). There was no rainfall in the previous 48 hour period prior to sampling.
Due to the Covid-19 crisis, we are not soliciting new volunteers for our 2020 sampling season. Please check back with us next season to volunteer.
In the North and South Rivers, our biggest concern regarding water quality is harmful bacteria from stormwater runoff. For the safety of our local community, we’ve been sampling and monitoring water quality at ten sites along the rivers for 27 years. RiverWatch is a volunteer-driven effort that monitors local waters for compliance with both swimming and shellfishing water quality standards.
In the past, poor treatment of wastewater was to blame, but we’ve worked with surrounding towns to help them eliminate polluted discharge from sewage treatment plants and reduced failing septic systems. Our work has led to dramatic reductions in bacterial counts but bacteria still finds its way into our streams, rivers and shellfish beds when rain falls on impervious (hardened) surfaces and drains untreated into our streams, rivers and coastal waters.
How does water quality affect shellfish beds?
Shellfish are filter-feeders. This means they filter the water when they feed off the bacteria and microscopic algae around them. If harmful bacteria is in the water, shellfish will consume it. And when we eat the shellfish, so do we. Because this can make us very sick, shellfish beds must often be closed especially after rainfall.
“We support the NSRWA because the work you do is vital to maintaining the river, to have it clean for the fish and for everyone. Healthy rivers don’t happen overnight! We are appreciative of your leadership and want to support you any way we can.”
Joelle Bianchi, NSRWA member, Scituate
Roughly every other week we collect water samples to test for bacteria – enterococcus at ten sites (the standard for swimming in brackish and salt water) and fecal coliform at five sites (the standard for shellfishing). This data is collected and compared to state standards in order to determine that week’s water quality. This week on June 29th, the two farthest upstream sites on the North River, Washington Street Bridge, exceeded the enterococcus swimming standard of 400 cfu per 100 ml. All other testing locations were below the standard, indicating the water was safe for swimming last week. As for shellfishing, 3 of 5 locations had fecal coliform levels above the shellfishing state standard. Driftway Park, North River Marine, and Julian Street Bridge were over the state standard of 14 cfu per 100 ml. When shellfish beds are open, only one of these sites is conditionally approved – North River Marine, because it is seaward of the 3A Bridge. Shellfishing is currently closed for the season.
On June 10, 2020 all 10 locations had enterococcus levels below the state standard for swimming. The threshold for swimming is 400 cfu per 100 ml, and the highest count from our 10 spots was at Willow Street Bridge on the South River, with 88 cfu per 100 ml. All spots were far below 400 cfu per 100 ml, indicating the water was safe for swimming at that time. As for shellfishing, 3 of our 5 spots had fecal coliform levels above the shellfishing state standard. Driftway Park, North River Marine, and Julian Street Bridge recorded results, respectively, of 26, 27, and 74 cfu per 100 ml, which are over the state standard of 14 cfu per 100 ml. Shellfishing is closed now anyway (shellfish harvesting stops on Mays 31 and will reopen on November 1st or possibly in October if the water quality remains suitable), so this data is for observational purposes only, but it is interesting to see if our shellfishing spots are meeting the state standard so we can continue to advocate for stormwater improvements. When we see these results, we know there is work to be done and hopeful improvements to be made.