It starts with a wriggling eel that can fit in your palm—skin so clear you can see its tiny heart pumping. Biologists capture it at the mouth of an upstate New York creek, near the Hudson River. These baby eels have traveled for a year from the Sargasso Sea, thousands of miles away, only to get stuck behind a small dam. For many decades, thousands of these blockages have choked streams from Maine to Maryland. Now, across the Northeast, a wave of removals is happening, with the goal of restoring natural flows, unblocking hundreds of miles of habitat for fish and wildlife, and reducing public safety risks.
In this piece, we’ll walk through how small dams built in the 1800s for local mills fell into disrepair, leaving behind walls that stopped fish in their tracks. You’ll meet ecologists, landowners, and local groups who decided there’s more to be gained by letting the water—and the fish—move freely again. We’ll also look at how money from federal programs and local partnerships allows old dams to come out. The result: migratory fish are returning, downstream flooding risk might shrink, and communities are rediscovering their rivers.
Small Dams Matter
When most folks think of dam removals, they picture giant structures like those on the Klamath or Elwha Rivers out west. But the Northeast’s puzzle looks different: tens of thousands of smaller dams, each just a few feet tall, built long ago to power local mills and keep ponds for livestock or small industries. Over time, many of these mills disappeared, but the dams remained.
For fish like American eels, alewives, shad, and river herring, even a short drop-off is an impossible hurdle. That means entire upstream spawning grounds sit off-limits. Or, if fish get stuck, they become easy prey. Meanwhile, behind these dams, sediment and algae build-up, the water might heat up, and oxygen levels can plummet. In some cases, it’s a stagnant pond that fosters invasive weeds or disease-carrying insects.
Many are not just pointless, they can be dangerous. Flash flooding can threaten houses downstream if a heavy storm breaks a structure. So removing these old barriers can help fish, people, and local ecology.
A Shift in Momentum
Dam removal isn’t new. A few small dams started coming down in the early 1900s. But it’s since the mid-2010s that the pace took off, especially after the 2021 Bipartisan Infrastructure Law injected hundreds of millions of dollars into habitat restoration. That same law recognized that many small, old dams are unsafe and that freeing rivers might reduce flood hazards.
By 2023, 806 small dams in the Northeast have been removed—80 across the country in that year alone. Some planned removals will push that number much higher. Andrew Fisk, Northeast director for American Rivers, says communities saw the damage that intense storms inflicted and realized they could improve resilience by letting rivers be themselves. So, local governments, private landowners, and environmental groups have begun working together, filling out grant applications to tear down unneeded dams.
Eels on the Saw Kill
In upstate New York, near Bard College, the Saw Kill Creek flows into the Hudson. American eels, no bigger than a pencil, appear each spring. Scientists place a funnel-shaped fyke net to catch them and see how many arrive. Then they carefully move them over the first of three old dams. If they do not, many eels would die or never spawn. For eels, a two-foot dam is as insurmountable as Hoover Dam.
Removing these small structures might let the eels continue upstream on their own, no volunteer transport needed. It’s a small tweak that can have big ripple effects: eels feed otters, birds, and bigger fish. They help tie the ecosystem together, bridging saltwater and freshwater. “Eliminating these obstacles is about letting nature do its thing,” says one fish biologist who’s spent years tagging eels.
Checking Off Removals, One Dam at a Time
1. Quassaick Creek, New York
In the city of Newburgh, the first of seven dams on this 18-mile tributary came down in 2020 with state funding. Since then, eels and even juvenile blue crabs have turned up. Removing the next dam is planned for 2025, and so on. For each removal, experts must handle possible sediment release, reroute roads, or add riparian plantings.
2. Massachusetts
The state geologist, Brian Yellen, found that most small dams store less sediment than you’d guess. So the standard fear that removing them will bury downstream habitats in muck doesn’t hold up. That’s good news for local boards who worry about big clean-up bills. If owners know it might be simpler and cheaper, they’re more likely to support removal.
3. Maine
Maine was among the first states to see small dam takedowns, especially on the Penobscot River. Although that included some bigger dams, smaller ones also vanished. The results have been spectacular for sea-run fish. Salmon, shad, and alewives now move upriver. Local towns are exploring rebranding from old mill sites to nature-based tourism.
The Ecological Benefits
- Restored Fish Migrations: Alewives, shad, herring, and eels can once again reach the upstream spawning sites that shape their life cycle. This quickly boosts fish counts.
- Healthier Water: Removing stagnant ponds can reduce algal blooms. River flows flush out sediment, distribute nutrients more evenly, and keep water cooler.
- Better Habitat for Bugs and Critters: River insects thrive in free-flowing conditions. That feeds everything from trout and eels to otters and kingfishers.
- Reduced Flood Risk: Old dams can fail under heavy rain, unleashing destructive floods. Clearing them helps the river manage storm flow on its own, which can avoid expensive property damage.
After a dam is gone, says Jeremy Dietrich, an aquatic ecologist, “You see streams bounce back to what you’d expect in a matter of a few seasons, in terms of insects, oxygen levels, sometimes fish. It’s as if the dam was never there.”
Public Safety and Liability
Many owners, from towns to private landholders, realize they face major liabilities if a dam collapses. Insurance might be expensive or impossible to get. Some might face repeated warnings from state inspectors. Taking out the dam can be cheaper than repairing it, plus it kills two birds with one stone: fix the safety risk and help the environment.
In Pennsylvania, for example, more than 390 small dams have disappeared since 1912, 107 from 2015 to 2023. Some were in disrepair, others were simply no longer used. Letting them stand would mean upkeep and potential legal exposure if a flood hits.
Steps to Remove a Dam
Dam removal isn’t as simple as sending a backhoe to smash the concrete:
- Check Ownership: Identify who owns the dam. This can be complex if it’s on private land or if multiple parties have claims.
- Permits and Studies: Groups must do an environmental review, see if toxic sediment is behind the dam, and evaluate whether the project might worsen flooding or hamper water supply.
- Apply for Funding: Government and nonprofits offer grants, but these require thorough proposals that show fish passage benefits, public safety gains, or clear environmental advantages.
- Plan Restoration: Once the dam is gone, shores might need replanting with native trees or shrubs. This helps control erosion and shade the water.
- Construction: Crews might build a temporary channel so the water can bypass the work zone, then gradually remove the barrier. Sometimes partial removal or fish ladders might be the answer if the dam has other functions.
- Follow-Up: Biologists often watch fish runs, measure water quality, and check for new invasive plants.
Balancing Dam Removal and Other Solutions
Some big questions remain. Not every small dam is worthless. A few help maintain wetlands that house rare species or are used by local farmers for irrigation. Others might be scenic spots. Experts must weigh the trade-offs: do the ecological upsides of removal top the local uses?
One alternative is installing fish ladders or bypass channels. But fish ladders can be expensive or less effective for certain fish, particularly eels that climb wet surfaces but might not handle typical ladders. Another fix is to set the dam’s height lower to let water pass more easily. That’s cheaper but might still hamper migrations.
People, Partnerships, and Funding
Environmental nonprofits like American Rivers, The Nature Conservancy, or Riverkeeper help owners navigate these steps, bridging them to grants from NOAA or the U.S. Fish and Wildlife Service. Town officials get behind the plan once they see success stories, such as a rebound in local fish that draws anglers or reduces the threat of dam-related flooding.
The Infrastructure Law poured about $800 million into fish passage nationwide, but that money might be delayed or reduced depending on future government policies. So time is of the essence. These groups try to build momentum, and with each success story—like a local eel population bouncing back—more owners might jump in.
Life After a Dam
Shortly after removal, people might see bare ground or leftover debris. It can look messy. But nature is surprisingly quick to retake space. By the next growing season, vegetation sprouts where pond margins once stood. In the water, species that prefer swift flows—like caddisflies—show up. Small fish find new nooks to spawn.
Over time, the chance of bigger fish returning rises. Some communities add a little platform or walkway by the newly freed water for people to watch eels or alewives. Town businesses might offer fishing gear or tours. And real estate near a healthy, scenic stream can go up in value, offsetting any worry about losing a “pond” feature.
Tying It All Together
From Maine’s rocky waterways to Maryland’s tidewater creeks, the quiet wave of small dam removal might shift entire watersheds. Eels and shad in one tributary can lead to recovering populations in a bigger river. Their presence rebalances the food web. Meanwhile, local folks see fewer flood scares, potential new tourism, or at least some peace of mind that a crumbling dam won’t give way in a heavy storm.
But it’s not instant: Each project can take years, from concept to completion. Some communities need to see thorough examples of better fish runs or safer flood plains before giving up their dam. Others worry about losing their pond, or the scenic reflection it offers. The process involves public meetings, listening sessions, sometimes compromise. Not every dam is going away. But more of them are, day by day.
How You Can Help
- Learn About Local Dams: Check if your neighborhood has old mill ponds. Ask local conservation groups if a removal is planned or possible.
- Support Removal Efforts: Volunteer or donate to nonprofits like American Rivers, Riverkeeper, or The Nature Conservancy that champion fish passage.
- Back Public Funding: If you see city or state proposals to fund dam removal or watershed restoration, voice your support.
- Spread Success Stories: If a nearby creek had a dam removal, share any ecological rebound or flood prevention outcomes. Word of mouth changes attitudes.
A Last Word
For the glass eels in the palm of a biologist’s hand, getting around a dam is a matter of survival. For the families downstream, an old, weak dam can be a serious risk each flood season. So tearing down these small barriers turns out to be a win for both fish and humans.
While not as flashy as demolishing a giant mega-dam, every small structure removed is a meaningful step. It’s a story that merges science, landowner cooperation, and community pride. And as these free-flowing waters come back to life, we can watch fish slip through rapids they haven’t seen in a century, a sign that even modest changes can have a big impact on restoring the Northeast’s watery heritage.