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Even after a dam has outlived its usefulness, removing it is rarely easy. It might require public outreach, permitting, dredging, engineering, regrading, replanting...the list goes on.
But when a dam no longer serves its intended purpose, and the owner supports removing it, it’s usually worth the trouble to do so.
Removing dams that are obsolete, derelict, or both, improves water quality, reduces flooding risk, makes boating and swimming safer, and opens habitat to fish and fishing.
And these outcomes materialize fast. Research shows that fish are often able to find their way to historical upstream habitat within weeks; river channels can stabilize within months; and communities can see reduced water-treatment costs within a year.
Conservation partners in the Delaware River watershed have long been working to identify and take down derelict dams to improve the lives of people and wildlife in this densely populated, four-state region.
But one of the biggest challenges they face isn’t engineering or permits. It’s the need for more practitioners with the knowledge and skills to remove dams.
Building capacity for dam removal
While the mainstem of the Delaware River is free flowing, its tributaries are saddled with more than 1,400 dams, way more than any single organization can remove or upgrade.
“If we want to ramp up the pace of dam removals, we need more people removing dams,� said Michelle DiBlasio, freshwater restoration manager for The Nature Conservancy in New Jersey.
That’s why The Nature Conservancy’s dam removal initiative also helps build capacity. With support from the U.S. Fish and Wildlife Service’s Delaware Watershed Conservation Fund, the organization held free workshops on dam removal for practitioners in 2023 and 2024 and plans to continue them at least through 2026.
In the first year alone, The Nature Conservancy offered two Dam Removal Project Manager training workshops attended by a total of 85 people. In a survey of attendees after the fact, thirty-two reported that they were working on a dam removal.
The Nature Conservancy has also offered one-day workshops on fish passage fish passage
Fish passage is the ability of fish or other aquatic species to move freely throughout their life to find food, reproduce, and complete their natural migration cycles. Millions of barriers to fish passage across the country are fragmenting habitat and leading to species declines. The U.S. Fish and Wildlife Service's National Fish Passage Program is working to reconnect watersheds to benefit both wildlife and people.
Learn more about fish passage as part of this effort.
“The workshops have provided a valuable experience for dam-removal practitioners, new and old, to network while sharing insight on the vast array of technical and non-technical intricacies of this field,� said Bryan Sojkowski, a fish passage engineer with the Service who led one of the workshops.
In addition to training, The Nature Conservancy is helping professionals learn on the job by inviting contractors and engineers who are new to dam removals to bid on straightforward projects.
Because, while dam removals are often complicated, occasionally, the universe gives you an easy one � or two. Why not use the opportunity to teach more people how to remove dams?
Entry-level dams
The Cedar Grove and No Name dams on New Jersey’s Lower Pequest River were not complicated dams to remove.
“They were both in forested areas, with no utilities or roads nearby,� said DiBlasio.
One was partially breached already. “There were trees growing out of the top.�
As for the owners?
“None of them knew they owned a dam,� she said.
Cedar Grove was owned by a private landowner who did not live on site � the land adjacent to the dam was forested and primarily used, with permission, by anglers to access the river. Located near a state-owned fish hatchery, Cedar Grove had become a popular spot to fish for trout. But the derelict dam was a safety hazard, and thus a liability for the owner, who was glad to see it go.
No Name was owned by two separate entities, with undeveloped parcels on either side of the river. In New Jersey, land ownership, and dam ownership, extends to center line in a stream.
One half was owned by a local business that leased a cleared part of the parcel for farming; the other half was owned by an order of Spanish-speaking nuns with a history dating back to the 13th century. When DiBlasio approached them, with a translator, to ask about removing it, they said: “If it’s good for the river, it’s good for us.�
Returns on river investments
Indeed, removing these dams is good for the river, its inhabitants and the surrounding communities. If you need evidence, just cruise up U.S. Route 94 in New Jersey and check out the Paulins Kill River, where The Nature Conservancy, the Service, and other partners have removed four dams since 2019, opening 45 miles of the mainstem and tributaries for migratory and resident fish species, and creating more opportunities for people to fish for them.
Last year, state biologists documented an American brook lamprey in the Paulins Kill for the first time � this resident species relies on well connected aquatic corridors for survival. “It’s an indicator species for healthy systems,� DiBlasio said.
Building on success in the Paulins Kill, The Nature Conservancy has prioritized reconnecting the Lower Pequest, a river with the potential to offer similar returns for wildlife and people.
Last year, the organization completed the removal of the No Name and Cedar Grove dams last year with help from contractors new to the field. EHS Support, a consulting firm that focuses on environmental, health and safety projects and employs engineers, hydrologists, biologists and other specialists, is one of those contractors.
“Our team had the relevant skillsets to do dam removals, but no practical experience,� said Greg Murphy, principal scientist for EHS Support’s sediment and risk assessment division.
When The Nature Conservancy opened the bidding process for removing the Cedar Grove and No Name dams, specifying that it was seeking firms with no prior dam-removal experience, Murphy said, “It was the perfect fit.�
Steppingstones and cobbles
In fact, there was widespread interest.
“The response was overwhelming,� DiBlasio said. “We had seven firms bid both jobs, which enabled us to hire different companies for each project and give more people opportunities to learn.�
EHS Support was selected to design and manage the removal of the Cedar Grove dam, with West Bay Construction doing the heavy machinery work to take it out.
“It was a great steppingstone for a firm like ours because it was not a complicated project,� Murphy said.
The dam, constructed with cobbles in the 1800s and later reinforced with concrete, was last used in the 1920s by the Cedar Grove Ice Company at Bridgeville to produce ice, which was trucked to customers by an all-women delivery team. Removing it in 2025 took just one excavator several hours.
“Permitting was the most challenging aspect,� Murphy said. Despite being a relatively straightforward project, regulatory review took 10 months.
Otherwise, Murphy said, “The rest of the work was not really new to us.�
That included designing a temporary access route to transport the heavy machinery to the dam with minimal disturbance to the streambank and adjacent forest and creating a plan for restoring the disturbed areas with mulch and plantings afterwards.
They also engineered the regrading of the stream bed to historical conditions using the cobbles removed from the dam.
A part of progress
For Murphy, the project was rewarding both personally and professionally.
He grew up in Warren County, which the Pequest runs through, and his dad worked at the county courthouse, just three blocks from the river. “Whenever I visited my dad on his lunch breaks, we’d walk down to the Pequest,� Murphy said.
After graduate school, Murphy spent 10 years working as a fish biologist for state wildlife agencies � first in Delaware then in Pennsylvania � helping manage fisheries resources in and around the Delaware River. He saw for himself the need to remove dams to bring back populations of migratory species like American shad and American eel.
»Ê¹ÚÌåÓýappÏÂÔØ on the project on the Lower Pequest has been a full-circle experience, returning him to his roots and giving him an opportunity to restore access to habitat he knows fish need.
“There’s still a number of dams to go, but we’re making progress,� Murphy said.
With the Cedar Grove and No Name dams gone, there are only two barriers left on the Lower Pequest. They’re coming down soon too, with support from the Service’s National Fish Passage Program. Their removal will restore natural flow to 10 miles of the mainstem to improve water quality, open access to 50 miles of cold-water tributaries for fish, enhance safe recreational opportunities, and reduce flooding in communities near the confluence of the Delaware River.
Now Murphy’s company, and others that are gaining experience in dam removal through this initiative, are equipped to accelerate progress in other parts of the watershed.
“We are definitely looking to leverage this experience to secure future contracts,� he said, adding, “We’re ready for a more complex project.�
