Third Herring Brook is a five-mile tributary to the North River that forms a border between Norwell and Hanover. It plays an important role in supporting river herring. The North and South River Watershed Association began their Third Herring Brook Restoration Project in 2012, focusing on restoring the fish passage for river herring and Eastern Brook Trout. The Restoration Project involved removing 3 of the 4 dams and adding a fish ladder under Rt 123 for fish to access Jacobs pond.
From 2014 to 2020, Mill Pond Dam, Tack Factory Dam, and Peterson Pond Dam were removed and reclaimed 5 miles of mainstream and 9.7 miles of restored habitat for fish. Third Herring Brook has also undergone changes from the removal of two concrete weirs in 2022 during the Hanover Crossing Mall renovations. Additionally, boulders were placed at the base of a bedrock to improve fish passage. The weirs and bedrock caused drops in the stream that would not be passable in lower flows.
The brook has since welcomed increased numbers of Eastern Native Brook Trout and became classified as a Coldwater Fish Resource by the Commonwealth of Massachusetts.
The water quality of Third Herring Brook was last monitored in 2017 and the brook was listed as impaired for Escherichia Coli (E. Coli) and Fish Passage Barrier in the Massachusetts Integrated List of Waters for the Clean Water Act 2022 Reporting Cycle. The E. Coli impairment is based upon data collected by MassDEP in 2016. MassDEP staff collected E. Coli and Enterococci bacteria samples at the Tiffany Road/East Street crossing in Norwell/Hanover, west of Tiffany Road, within the stream channel just upstream of the old Tack Factory Dam location and at the Broadway/River Street bridge. The sampling took place during the summer of 2016 and 2017.
NSRWA has been interested in resampling Third Herring Brook to identify any changes in water quality following the multiple dam removals and renovations at Hanover Crossing. So, when the X-Cel Conservation Corps reached out to us looking for a project, we knew exactly where to go.
X-Cel Conservation Corps (part of X-Cel Education) breaks the cycle of poverty by preparing Boston youth for careers in water management and conservation that lead to economic self-sufficiency. Key components of the X-Cel Conservation Corps include workforce readiness development, paid conservation projects to improve water quality and build environmental resilience in Eastern Massachusetts, classes to prepare for wastewater operator license, and paid internships in the water management field. It’s a terrific program that we are proud to partner with. You can find out more about them here.
In October and November 2024, X-Cel joined NSRWA’s staff to collect bacterial samples and measure water quality parameters such as temperature, conductivity, and dissolved oxygen. Samples were then brought to the laboratory at the Cohasset Center for Student Coastal Research (CSCR) for processing and analysis. Both the field collections and laboratory analysis were used as training opportunities for the X-Cel team members. A huge thank you to Jack Buckley and the CSCR staff for donating their time and space to this effort!
The sampling was conducted at two of DEP’s historic sampling sites and two new sites upstream of our restoration work (see map below).
- THB02: MassDEP site, representing the furthest downstream end of Third Herring Brook before entering the North River
- THB05: MassDEP site, representing Third Herring Brook near the Norwell and Hanover drinking water wells
- THB-B: New site for 2024, representing the upstream of NSRWA’s restoration projects
- THB-A: New site for 2024, representing the discharge from Jacobs Pond
Results:
- THB02: At this downstream site the bacterial concentrations were similar to past sampling by MassDEP with values of 75.4 MPN (Most Probable Number) for Enterococci and 120.7 MPN for Fecal coliform. In their 2017 sampling MassDEP “concluded that evidence does not support the presence of a significant human source of bacteria to the Third Herring Brook watershed, upstream of Broadway.”
- THB05: This site had been of concern to MassDEP based on a very high bacteria concentration in August 2017 of 3,873 MPN. Although they identified high concentrations here as “intermittent” and suggested that it “may have been due to August low flow/imminent dry-up and does not appear to be having a measurable impact on the quality of the downstream sections of the brook.” Our 2024 sampling also found variability at this site, although not with the excessive concentrations seen in 2017. The October 28 and November 4 Fecal coliform results were 98.5 MPN and 549.3 MPN respectively. This is a site we plan to monitor under varying flow conditions.
- THB-B: We selected this new site to be upstream of all our recent restoration work and also generally upstream of the new development of Hanover Crossing. The results here were highly variable and somewhat concerning. The October 28 Fecal coliform result was 185 MPN, while the November 4 result was 2,419.6 MPN. The source of this high result is unclear. There are many potential sources in this stretch of the brook including the discharges from Route 3. It is a site that we will target for future sampling, including possible human marker analysis.
- THB-A: This site just downstream of Jacobs Pond represents the headwater conditions of Third Herring Brook. Bacterial concentrations here were low at 89.9 MPN and 16.9 MPN respectively for the two sampling events.
- The other measured water quality parameters (Temp, Oxygen, and Conductivity) were all well within the indicators of a healthy stream.
We anticipate further sampling in Third Herring Brook to assess summer time conditions and as part of the Jacobs Pond fish ladder project. Stay tuned for more updates in 2025!