Some fish are permanent residents of the North and South Rivers and their tributaries, while others visit only to feed or spawn. There are two categories of visiting fish: anadromous and catadromous. Anadromous fish (such as herring, shad and alewives) live part of their lives at sea, then migrate up river to spawn in fresh water. Catadromous fish (such as the American eel) breed out at sea, and the young travel up the river to feed and grow. These fish depend on free flowing rivers and streams for their spawning needs and livelihood.

Every spring, thousands of these fish attempt to make their way upstream in our watershed. From as early as 1640, their passage has been blocked by numerous dams and other obstructions along the North and South Rivers and their tributaries, that prevent them from reaching their destination.

By the mid 1700's, the stocks of anadromous fish were seriously depleted in the North and South Rivers as a result of these dams. It was not until 1790 was it required by law to establish ladders to facilitate passage up the river. Even so, many dams were not properly fitted with adequate facilities, and the anadromous fish species continued to decline for another 100 years. The fish eventually became so depleted that in 1880 it was required that ponds were artificially stocked. It wasn't until the 1960's when the anadromous fish returned in significant quantites, largely due to the construction of fish ladders by the Massachusetts Fish and Wildlife Service, and by this time many of the old unused dams had been breeched by floods.

Today some of the old dams still exist, and continue to block passage of herring up the tributary streams to spawn. The NSRWA has been working with the Massachusetts Bays Program and numerous regional partners including the MA Department of Marine Fisheries, MA Riverways Program, MA Office of Coastal Zone Management, South Shore towns, and private landowners to help restore anadromous fish passage at various sites on the South Shore. We have helped write multiple successful grants that have generated hundreds of thousands of dollars for fishway repair and restoration on the South Shore, particularly for the South River in Marshfield, Town Brook in Plymouth, and Third Herring Brook between the towns of Norwell and Hanover.

Third Herring Brook (3HB) Restoration Project

The Third Herring Brook is a tributary to the North River, located on the town line between Norwell and Hanover. The Massachusetts Division of Marine Fisheries has documented existing populations of anadromous fish on Third Herring Brook, including blueback herring, rainbow smelt, and sea lamprey. Historically, the fish travelled all the way to Jacobs Pond in Norwell, at the head of Third Herring Brook. Due to four dams along the length of the brook, their journey is but a fraction of that distance, and the potential spawning area is greatly reduced.

The NSRWA, with support of multiple project partners, has embarked on an ambitious and comprehensive effort to return anadromous fish to their historic spawning grounds in Jacob's Pond and restore the natural riverine functions of the Third Herring Brook tributary.

Restoring fish passage at all four barriers along Third Herring Brook will re-open five miles of free-flowing stream and 54 acres of spawning habitat. This habitat restoration shall be accomplished either through the installation of fish ladders (or other means of engineered fish passage) or the removal of the dams. Installation of adequate fish passage facilities at these points could potentially increase the available spawning areas by more than 500%. These fish provide a food source for recreational and commercially important fish species, both inshore and offshore. Wildlife such as ospreys, eagles, herons, and kingfishers will also benefit from the abundant food supply represented by increased anadromous fish runs.

In addition to increasing anadromous fish populations, there are multiple ecological and societal benefits of restoring fish passage along Third Herring Brook. If dam removal is a viable option, a fully restored free flowing river could add other benefits to the project including:

• Removed dam safety risks and associated liability costs;
• Saved taxpayer dollars;
• Improved water quality; and
• Improved aesthetics of the river;
• Increased fishing opportunities; and
• Increased recreational opportunities.

The NSRWA is addressing these four sites individually through a four-phase process, and Phase I (Mill Pond) is already underway with generous funding assistance from multiple project partners.

Phase I: Mill Pond Dam

The catalyst for the NSRWA's 3HB Restoration Project was the collapse of part of the Mill Pond Dam, the second of the four impoundments along Third Herring Brook. This dam is owned by the South Shore YMCA, and is located very close to the NSRWA office.

On February 9, 2001 a portion of the dam's concrete sluiceway collapsed, causing the dam to not be in compliance with the Massachusetts Department of Environmental Management's Dam Safety Regulations. As such, the YMCA was issued emergency authorization by MA DEM to remove to the dam's flashboards and lower the dam's water levels. The collapse of the sluiceway and subsequent removal of flashboards transformed Mill Pond into four acres of wet meadow, with 2.5 miles of free-flowing stream that has now re-established itself into its original channel.

While the dam had deteriorated and was dismantled enough that it could no longer retain the pond, the remaining dam structure still prevented fish passage at the site. To help determine the best option for restoring fish passage, the NSRWA worked with the Massachusetts Riverways Program and other partners to raised funds to conduct an "Alternatives Analysis" (funded in part by National Fish and Wildlife Foundation/NOAA 5-Star and the Gulf of Maine/NOAA Partnership). This analysis was completed by GZA GeoEnvironmental, Inc. in August of 2001. The study evaluated the feasibility of repairing the dam and building a fish passage structure versus permanently breaching it. Based on this study, the YMCA and project partners determined that the removal of the dam and its associated embankments were the preferable option. Project partners are currently navigating the lengthy permitting process to permanently remove the dam and restore the natural stream channel at the site.

If anadromous fish were able to reach this portion of the Third Herring Brook, they would be able to travel all the way up to Peterson's Pond Dam, behind the Hanover Mall. However, at this time they cannot reach the former Mill Pond area because they are stopped by the crumbling dam that creates the Tack Factory Pond, the first impoundment traveling upstream along Third Herring Brook.

Phase II: Tack Factory Pond Dam

Every spring you can see the alewives and blueback herring making their way up the Third Herring Brook, only to be stopped by the Tack Factory Pond Dam near Tiffany Road. The nine-foot high dam was built in 1928 to provide waterpower for a mill that is now demolished. Currently the dam is in failing condition, as classified by the MA Office of Dam Safety.

The NSRWA's immediate goal for Phase II of the 3HB Restoration Project is to help project partners and community stakeholders determine which method for restoring anadromous fish habitat will best balance the environmental, physical, and social issues facing the Tack Factory Pond.

As the leaders of this restoration effort, NSRWA needs environmental, physical and social data to help guide the decision making process. The NSRWA has received generous funding from multiple project partners to hire a qualified consulting firm to conduct a "Feasibility Study" to help project partners and community stakeholders determine the optimal fish passage alternative for Tack Factory Pond Dam. Alternatives to consider include: (1) repair/rebuild existing dam and install fish passage (the current state of disrepair will not support the construction of a fish ladder), (2) partial breach of the dam, or (3) full removal of the dam and restoration of the natural stream channel.

This Feasibility Study will compare the advantages and disadvantages of these different methods of fish passage and involve the collection/review of extensive information and data and evaluation of cost, environmental impacts, social impacts, ownership and future management issues, as well as financial and liability issues. Once presented with the relevant facts and issues regarding the Tack Factory Pond Dam, the project partners and Third Herring Brook Restoration committee can determine the most suitable fish passage method and can work towards implementing their plan.

An immediate benefit of restoring fish passage at the Tack Factory Pond Dam will be the opening of habitat up to Peterson's Pond, which is approximately 3 ¼ miles from the mouth of Third Herring Brook. Fish passage at Tack Factory Pond Dam will allow the fish to reach the restored habitat hopefully resulting from Phase I (Mill Pond Dam) of the Third Herring Brook Restoration Project.

For further information, or to get involved in the project, please contact the NSRWA office at 781-659-8168.

Downloadable reports:

• January 2005 NSRWA Newsletter: "Third Herring Brook Update" by Wendy Garpow, NSRWA Director of Community Programs
• August 2004 "Dam Fact Sheet" by NSRWA
• June 2004 Presentation by Steve Hurley (Fisheries Manager, MA Division of Fisheries and Wildlife) to the 3HB Community Information Meeting on June 22, 2004. no longer downloadable - please contact the watershed office for this report
• July 2003 Mariner Newspapers: "Rethinking Dams" by Samantha Woods, NSRWA Executive Director
• July 2002 NSRWA Newsletter: "A Journey Along Third Herring Brook" by Alison Demong, NSRWA Director of Community Programs