Improving Water Quality

Rivers Water Quality Gets Clean Bill of Health This Week!

9/9 Test results are a super clean bill of health for the waters – 10 out of 10 samples met all water quality bacteria standards for shellfishing, swimming and boating!

On the mornings of July 26^th and September 9^th, volunteers completed rounds of sample collection for the RiverWatch Water Quality Monitoring Programs. Across Pembroke, Hanover, Norwell, Scituate and Marshfield, 10 locations were sampled for enterococcus and 5 were sampled for fecal coliform, which are bacteria considered to be indicators of water quality and potential contamination. The samples are collected by volunteers, analyzed by Morrell Associates, then compared to Massachusetts state regulations to help better understand and communicate the current water quality of the North and South Rivers. The map provides a visualization of the most recent week’s results, while the chart contains the data from the entire summer.

On September 9^th, out of the 10 locations tested for enterococcus and 5 for fecal coliform, zero were above the Massachusetts swimming or shellfishing standards. The North River Mouth continued its consistency, as it has not logged any enterococcus all summer, which makes sense given its location. The highest fecal coliform count of the week was 10 cfu per 100 ml, while the Massachusetts threshold is 14 cfu per 100 ml. For enterococcus, Willow Street Bridge recorded 96 cfu per 100 ml, which is close to the Massachusetts enterococcus threshold of 104 per 100 ml, but still below. September 9^th was the second week this summer with zero sampling locations above the state standards, and that is always good to see.

Three weeks ago on August 26^th (see chart), we had 1 of 10 locations above the enterococcus standard, and 3 of 5 locations above the fecal coliform standard. The Washington Street Bridge had enterococcus levels of 170 cfu per 100 ml, which is above the Massachusetts threshold of 104 per 100 ml. Enterococcus at the Washington Street Bridge has been above the state standard four out of seven times, while some locations (like the Norwell Canoe Launch) have not been above once. For fecal coliform on August 26^th, 3 locations, the North River Marine, Damon’s Point, and Julian Street Bridge, were above the state standard. Enterococcus at the North River Marine was 14 cfu per 100 ml, which is right at the threshold of 14 cfu per 100 ml. Damon’s Point and Julian Street Bridge had enterococcus counts of 16 and 33 cfu per 100 ml, respectively, which are again above the Massachusetts standard. Fecal coliform at Julian Street Bridge has been above the state standard five times out of seven, making it the most frequent location to be above the threshold.

Testing Results from 8-12-20

On August 12th, 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 all of the locations were below the state thresholds for swimming and shellfishing. The state threshold for swimming is 104 cfu of enterococcus per 100 mL.  The state standard for shellfishing is 14 cfu fecal coliform per 100 mL. There was no rainfall in the previous 48 hour period prior to sampling. In fact, the last time the watersheds to the North and South Rivers received any rain was on August 5th, and the last time we received “wet weather” (for water quality monitoring purposes, a rainfall event >0.25″) was July 6th. A lack of stormwater during this significant drought has meant reduced stormwater pollution.

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.

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.