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A Rainy Summer Results in Higher Bacterial Counts Due to Stormwater Pollution

The North and South Rivers Watershed Association has been sampling water quality at 10 sites along the North and South Rivers for 27 years to evaluate the health of the rivers. This volunteer-driven program monitors the rivers every other week from the beginning of June to the end of August. We monitor for both swimming and shellfishing standards, each of which have specific concentrations of bacteria that are considered safe for humans, reported in cfu or colony forming units. In 2017 we switched from testing fecal coliform at all sites to focusing on the areas where shellfish could be harvested (both in conditionally open areas as well as estuarine areas that still support shellfish but are prohibited). We expanded our enterococcus testing to include all ten sites, since that is the current standard for swimming in brackish and marine waters.

On August 16, 2021, volunteers completed the sixth and final round of sample collection for this year’s RiverWatch Water Quality Monitoring Program. On this sampling date, all but two of the sites sampled for enterococcus met the Massachusetts state swimming standard of 104 cfu per 100ml. The following sites exceeded the state standard – Washington Street Bridge (140 cfu), and Keville Foot Bridge (110 cfu). This year, Washington Street Bridge was above the standard on four out of six sampling dates, and Keville Footbridge was above the standard on five out of six sampling dates. Keville Footbridge was a new site this year, replacing Willow Street Bridge farther upstream. Access is easier at Keville Footbridge for our volunteers.

Fecal coliform results collected only in the shellfish growing areas largely mirror the majority of this year’s sampling rounds in that all but one of the five locations tested was above the Massachusetts shellfishing standard. Driftway Park (52 cfu), North River Marine (35 cfu) Damon’s Point (29 cfu), and Julian Street Bridge (88 cfu) were above the state threshold of 14 cfu per 100 ml. The North River Mouth tested at 1 cfu this week, within the standard for shellfishing. This is the same distribution as the last round of sampling. Driftway Park, North River Marine, Damon’s Point, and Julian Street Bridge have been over the shellfishing standard every round of sample collection so far this year. Regardless of the data, these areas are closed for shellfishing until further notice as per state and federal regulations due to their proximity to the Scituate Wastewater Treatment Plant.

Attached to this week’s results chart is the final geometric mean data for each site, including both fecal coliform and enterococcus. Only Keville Footbridge had a mean that was above the swimming threshold for enterococcus with 249 CFU, and the North River Mouth had a mean that was below the shellfishing standard for fecal coliform with 5 CFU.

Over the years bacteria counts have diminished in the rivers due to Title V septic improvements, implementation of town sewerage and improved treatment and minimization of stormwater runoff – all of which the NSRWA has advocated for using these data to make the case for reducing pollution sources.

Thank you to the dedicated volunteers who helped with this program this year. If you are interested in volunteering next year please contact Sara Grady at sara@nsrwa.org or (781) 659-8168.

July 30, 2021 Results

On July 28th, 2021, volunteers completed the fifth round of sample collection for our RiverWatch Water Quality Monitoring Program. After having the samples analyzed for bacterial colony forming units (cfu), they are compared to the Massachusetts state water quality standards in order to help determine this week’s water quality.

This week all but two of the sites sampled for Enterococcus met the Massachusetts state swimming standard of 104 cfu per 100ml. The following sites exceeded the state standard, The Washington Street Bridge (270 cfu), and Keville Foot Bridge (5,400 cfu). For Washington Street Bridge and Keville Foot Bridge this is their third and fourth failures this year respectively. There was no Enterococcus sample taken from The Situate Waste Water Treatment Plant this week. As for the exceedingly high reading from Keville Foot Bridge we are unsure of its cause at the moment, though we are investigating.

As for fecal coliform, the results largely mirror the last round of sampling in that all but one of the five locations tested was above the Massachusetts shellfishing standard, Driftway Park (83 cfu), North River Marine (59 cfu) Damon’s Point (51 cfu), and Julian Street Bridge (140 cfu) this is above the state threshold of 14 cfu per 100 ml. North River Mouth tested at 6 cfu this week, within the standard for shellfishing. This is the same distribution as the last round of sampling. Driftway Park, North River Marine, Damon’s Point, and Julian Street Bridge have been over the shellfishing standard every round of sample collection so far this year. Regardless of the data, these areas are closed for shellfishing until further notice as per state and federal regulations due to their proximity to the Scituate Wastewater Treatment Plant.

Thank You to the Norwell Womens Club for Sponsoring Three Weeks of Water Quality Testing!

NSRWA Executive Director Samantha Woods accepts a $1,000 donation from Shannon Toland of the Norwell Womens Club. The donation helps to support the RiverWatch Water Quality Monitoring program and will be used to help pay the costs of water sample analysis. Thank you Norwell Women’s Club! If you would like to sponsor a week of testing, contact Gabriela Silva at gabriela@nsrwa.org.

July 15, 2021 Results

On July 14th, 2021, volunteers completed the fourth round of sample collection for our RiverWatch Water Quality Monitoring Program. After having the samples analyzed for bacterial colony forming units (cfu), they are compared to the Massachusetts state water quality standards in order to help determine this week’s water quality.

This week only three of the sites sampled for Enterococcus met the Massachusetts state swimming standard of 104 cfu per 100ml. The sites that were within the state swimming standards are, Corn Hill Lane, the Scituate Wastewater Treatment Plant, and the North River Mouth. The following sites exceeded the state swimming standard, The Washington Street Bridge (110 cfu), Norwell Canoe Launch (130 cfu), Driftway Park (140 cfu), North River Marine (120 cfu), Damon’s Point (110 cfu), Julian Street Bridge (150 cfu), and Keville Foot Bridge (280 cfu). For the majority of the sites that failed, this was the first week in which they have done so, in the case of the Washington Street Bridge and the Keville Foot Bridge this is their second and third failures respectively this year. Stormwater runoff after rain events is the cause of the exceedances as the stormwater runs off the pavement with little to no treatment for bacteria.

As for fecal coliform, the results largely mirror the last round of sampling in that all but one of the five locations tested was above the Massachusetts shellfishing standard; Driftway Park (110 cfu), North River Marine (110 cfu) Damon’s Point (87 cfu), and Julian Street Bridge (230 cfu). These 4 were above the state threshold of 14 cfu per 100 ml for shellfishing. North River Mouth tested at 3 cfu again this week, within the standard for shellfishing. This is the same distribution as the last round of sampling. Driftway Park, North River Marine, Damon’s Point, and Julian Street Bridge have been over the shellfishing standard every round of sample collection so far this year. Regardless of the data, these areas are closed for shellfishing until further notice as per state and federal regulations due to their proximity to the Scituate Wastewater Treatment Plant.

June 30, 2021 Results

On June 30th, 2021, volunteers completed the third round of sample collection for our RiverWatch Water Quality Monitoring Program. After having the samples analyzed for bacterial colony forming units (cfu), they are compared to the Massachusetts state water quality standards in order to help determine this week’s water quality.

This week all but one of the sites sampled for Enterococcus met the Massachusetts state swimming standard of 104 cfu per 100ml, Keville Foot Bridge (200 cfu). This is the second week in a row that Keville Foot Bridge has not met the Massachusetts swimming standard for Enterococcus.

As for fecal coliform, all but one of the five locations tested was above the Massachusetts shellfishing standard, Driftway Park (100 cfu), North River Marine (51 cfu) Damon’s Point (54 cfu), and Julian Street Bridge (65 cfu) this is above the state threshold of 14 cfu per 100 ml. North River Mouth tested at 3 cfu, within the standard for shellfishing. This is the same distribution as the last round of sampling. Driftway Park, North River Marine, Damon’s Point, and Julian Street Bridge has been over the shellfishing standard every round of sample collection so far this year. Regardless of these data, these areas are closed for shellfishing until further notice as per state and federal regulations having to do with its proximity to the Scituate wastewater treatment plant.

June 19, 2021 Results

 

 

 

 

 

 

On June 16th, 2021, volunteers completed the second round of sample collection for our RiverWatch Water Quality Monitoring Program. After having the samples analyzed for their colony forming units (cfu), they are compared to the Massachusetts state standards in order to help determine this week’s water quality. The week of June 14th, all but two of the sites sampled for Enterococcus met the Massachusetts state swimming standard of 104 cfu per 100ml, Washington Street Bridge (140 cfu) and Willow Street Bridge (160 cfu). As for fecal coliform, all but one of the five locations tested was above the Massachusetts shellfishing standard, Driftway Park (130 cfu), North River Marine (92 cfu) Damon’s Point (50 cfu), and Julian Street Bridge (300 cfu) this is above the threshold of 14 cfu per 100 ml. North River Mouth tested at 8 cfu, within the standard. Even with this data it should be said that this area is still closed until further notice as per state and federal regulations having to do with its proximity to the Situate wastewater treatment plant.

 

June 2, 2021 Results

On June 2nd, 2021, volunteers completed the first round of sample collection for our RiverWatch Water Quality Monitoring Program. After having the samples analyzed for two types of bacteria the results are compared to the Massachusetts state standards for swimming and shellfishing in order to help determine this week’s water quality. The week of May 31st, all of the sites sampled for enterococcus met the Massachusetts state swimming standard of 104 cfu per 100ml. For fecal coliform, all of the five locations tested were above the Massachusetts shellfishing standard – Driftway Park (260 cfu), North River Marine (400 cfu) Damon’s Point (300 cfu), North River Mouth (39 cfu), and Julian Street Bridge (88 cfu) were all above the threshold of 14 cfu per 100 ml. Out of these five locations, one (North River Marine, 400 cfu/100mL) also tested above the pre-2007 swimming threshold of 400 cfu per 100 ml.