Peterson Pond dam before removal.

By Samantha Woods
NSRWA Executive Director

My very wry husband often says to me I would be out of jail by now if I had just blown up the dams in our rivers with some C4 instead of taking the longer but higher road of removing them through the proper channels. But, part of the reason it takes so long to remove a dam is that no single entity can do it alone, and each project requires many partnerships to be successful.

The Peterson Pond dam on the Third Herring Brook, is by the Hanover Mall and the most recent of three dams, all in private ownership, that the NSRWA has removed on this brook. We actually started discussions with all the owners of the three dams back in 2001!  But to remove a dam, first and foremost, you must have buy-in from the dam owner. In the case of Peterson Pond dam, the Hanover Mall’s (now Hanover Crossing) current owner is a company called Peco Real Estate Partners or PREP. They purchased the property in 2016 to redevelop it, but prior to that, the mall property had changed hands numerous times, including being in bank ownership since 2010. It wasn’t until PREP purchased the mall and decided to redevelop and invest in the property that the owners were willing to consider partnering with us to remove the dam. Owner buy-in is the main ingredient to any dam removal project; without it, nothing else moves forward.

Peterson Pond Construction Meeting with Hanover Crossing, GZA Engineers, SUMCo Construction, Division of Ecological Restoration, NSRWA and MassBays Staff.

The next ingredient in the recipe for dam removal is funding. Dam owners want to alleviate the maintenance and liability of the dam’s failure, but when faced with removal costs, they are often unable to meet those costs alone. The cost of removing a dam varies depending upon the complexity and scale of the project, but in our limited experience on the Third Herring Brook, the costs ranged from $385,000 (Peterson Pond dam) -$450,000 (Tack Factory and Mill Pond dam each) not including the time of our staff or the staff of our state and federal partners. Dam removal costs are highly site-specific. Reasonable cost estimates can be made only after a feasibility study examines if there are any obstacles to removal that might pose issues. The good news is that this a one-time cost – once the dam is removed, there is no longer any need to maintain that infrastructure or worry about it failing!  

GZA and Division of Ecological Restoration staff standing in the Third Herring Brook at site of the former Peterson Pond dam.


Funding partners are also critical and no one funder will pay for an entire project. There are many grant opportunities available at the state and federal levels and private foundations that are interested in habitat restoration. In the case of our dam removal at Peterson Pond, we relied upon Sara Grady, NSRWA Watershed Ecologist and South Shore Regional Coordinator for the
MassBays National Estuary Partnership program, to secure grant funding. Sara works in our office as our Watershed Ecologist, and MassBays covers a portion of her salary to help with the scientific monitoring and fundraising efforts on restoration projects. MassBays is funded through the US EPA, and they are critical partners in helping us leverage other resources. Sara successfully wrote grants to the Massachusetts Division of Ecological Restoration, Massachusetts Environmental Trust (which receives funds from the sale of license plates with the Whale Tail), US Fish and Wildlife Service in partnership with Eastern Brook Trout Joint Venture, and the National Fish Passage Program, and NOAA’ National Marine Fisheries Service’s Habitat Restoration Program for the Peterson Pond dam removal. In addition to cash to pay for removing the Peterson Pond dam, we also partnered with other organizations like Southeastern Mass Trout Unlimited, Sea Run Brook Trout Coalition, and Mass Wildlife to conduct monitoring for eastern brook trout in the system. The NSRWA’s other staff and its members are also critical partners. Technical assistance, project management, public outreach, and citizen science monitoring are all valued as matching funds that leverage grant money. Whether you knew it or not, your donations of time and money make you a funding partner in our dam removal project! Thank you!

Town Conservation Commissions and state and federal agencies play an important role as well through review of the permits needed to remove a dam. We will save permitting for another article but suffice it to say that dam removals would not happen without their support and partnership to obtain the permits. In the Peterson Pond dam case, because the Third Herring Brook is the town boundary, we needed both Norwell and Hanover as partners in the project. 

Site of former Peterson Pond dam after removal.

Civil engineers, wetlands scientists, land surveyors, professional archeologists, and dam removal construction contractors are all partners needed at different stages to complete a dam removal project. Civil engineers conduct modeling to determine if there will be any changes to the floodplain, and design the appropriately-sized river channel to pass fish and different-sized storm events. Wetlands scientists must evaluate the wetland resource areas that will be altered. Land surveyors map the site and elevations both before and after the dam is removed. Since these dams are often over 100 years old and have long histories, professional archaeologists must document any historical resources at the site. Finding construction contractors with dam removal experience is also critical as reforming a waterway is as much art as science and engineering. For the Peterson Pond dam project, we partnered with GZA Consulting Engineers for engineering, permitting, surveying and design, Public Archaeology Labs (PAL) for the historical review, and SUMCo for construction.

As you can see, if you made it this far, it takes a lot of partners to accomplish a dam removal project and each one plays a different role in moving the project forward. The Peterson Pond dam took three years to permit, fundraise for, and remove once the owners decided to move forward with the project but, from our initial conception of the project, it took 18 years! By removing the Peterson Pond dam (and Tack Factory and Mill Pond dams) 4 miles of the Third Herring Brook and 9.7 miles with tributaries included have been reconnected for river herring and trout to reclaim and expand their populations! 

I hope you will join us for our upcoming New Year’s Day Third Herring Brook Dam Breakthrough Tour from 1 – 4 pm. It is free but you must register to attend.