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As river restoration efforts in the U.S. grow stronger and we see the positive impact of dam removal, many are wondering if dams still have value.
Over 24 hours on August 18 and 19, torrential rain flooded much of Suffolk County, Long Island. It was too much for the 115-year-old Mill Pond Dam, which broke from the rapid water flow, draining the pond. For the first time since 1910, the pond’s water made its way into the Long Island Sound and other nearby waterways, according to News 12.
Harbor Road, which borders the pond, collapsed as the road’s asphalt split into huge pieces and slid into the pond. The pond is part of the Avalon Nature Preserve, a 216-acre conservation area nestled next to the picturesque shopping and cultural center of Stony Brook Village, and surrounded by the homes of community members — one of which split in half and floated away. Surviving ducks — along with the swans, fish, and other animals of the pond — became homeless overnight.
As the rain let up, residents began to gather. Many cried as they shared their experiences at the pond over the years with reporters. Animal rescue workers and volunteers fished stuck turtles — including an 80-lb snapping turtle believed to be over 60 years old — out of the muck. Less than ten miles away in nearby Smithtown, a similar scene played out as another dam failed, draining Stump Pond.
These breaches may sound unprecedented, but dam removal experts have been warning about these potential outcomes for years. As extreme weather becomes more frequent and intense, aging dams put surrounding populations at greater risk.
“Not all dams present a serious hazard to people, but dam failures are likely to become more of a threat than they have been in the past,” said Paul Woodworth, a senior program manager at Save The Sound, an environmental nonprofit focused on protecting Long Island Sound and waterbodies in the surrounding shoreline communities. He estimates that 20% or less of U.S. dams still serve a valuable function to society, which means, of course, that he believes that 80% do not. Yet, almost every removal project that Woodworth has worked on has been met with resistance, sometimes due to a nostalgic attachment.
The Long Island breakages coincide with a growing question of whether dams are a relic of a past. While there are persuasive arguments against dams, not everything about them is inherently bad. Proponents have long championed hydropower dams as a clean energy alternative to fossil fuels. When released, water stored in a dam’s reservoir spins a turbine that generates energy. (Researchers are beginning to look for better ways to generate hydropower without completely blocking rivers and their animal inhabitants. One early study of a new turbine design had a 100% survival rate for American eel swimming through.) Still, dams’ disadvantages are many.
More than 2,100 U.S. dams have been removed since 1912, but the era of dam removal and river restoration projects ramped up in 1999 with the removal of Edwards Dam on Maine’s Kennebec River. The main reason for this push is that more than 85% of U.S. dams are over 50 years old and require necessary, expensive repairs.
American Rivers, a 51 year-old nonprofit that works to protect rivers nationwide, calls the Edwards Dam removal a “turning point because it was the first time the Federal Energy Regulatory Commission ordered a dam removed because its costs outweighed its benefits.”
Since 2017, approximately 50 to 100 dams have been removed each year. Summer 2024 saw the much-lauded completion of the largest dam removal in U.S. history: The fourth and final dam blocking the Klamath River, which runs about 257 miles in length from Oregon to California, came down in August.
“There’s lots of misconceptions about dams, one being that every dam provides flood control, which is absolutely not the case,” Woodworth said. Unless a dam is specifically built for flood control (only about 18 percent of them are, according to the National Inventory of Dams), it typically doesn’t provide it — at least, Woodworth said, not in a safe or effective manner. American Rivers’ website notes that dam failures have prompted hundreds of thousands of Americans to evacuate their homes in the past few years and racked up many millions of dollars in property damage.
Woodworth recalls a dam that was on the verge of breaking in Connecticut where a downstream community had to be evacuated. Instances like that have prompted a shift in the way the state addresses dam safety. Connecticut recently passed legislation that would allow the Department of Energy & Environmental Protection to issue immediate repair orders to dam owners when the structure poses a substantial threat to the surrounding community. “We know that many of the dams across Connecticut are actually derelict and obsolete,” Woodworth said. “They’re not being maintained or even inspected on a regular basis.” This lack of upkeep is especially worrisome considering how old these structures are. “Connecticut is dominated by a lot of former mill dams,” Woodworth said. “These are dams that were probably first built [around] the 1600s as a sawmill but then were rebuilt to be a textile mill in the 1800s.”
In April 2024, American Whitewater and Earthrise Law Center launched an initiative to address this issue on a national scale. The Deadbeat Dam Law Project aims to force the removal of crumbling hydropower dams that are no longer operational. Often, owners will surrender their federal hydropower licenses when maintaining the dams becomes too costly, but they are not required to remove the dams. And unless the state is monitoring the inactive dams, they can deteriorate and become a danger.
When a dam is removed, Woodworth says restorative effects become visible almost immediately. Dry sediment around the waterbodies gets hydrated and vegetation begins to grow again. “There's a pretty interesting transition that occurs from converting a site from a backwater or ponded environment back into a free-flowing riverine setting,” he said.
Save The Sound has focused on restoring migratory pathways that fish traveled before barriers went up. The organization has seen some fish species, like American shad and sea lamprey, rebound. “We see them getting farther up into the watershed than they had before, which is all a great sign for us,” Woodworth said.
Studies commissioned by the tribe — which drew data from their healthcare records — found connections between the establishment of Iron Gate Dam and the deterioration of community health.
River herrings are also repopulating. They play a critical role in the local food chain. Eagles, osprey, and striped bass all feed on them. “Even small mammals will likely take advantage of new protein and nutrient sources that they haven’t had the access to,” Woodworth said. Dam removals lead inevitably to improved fish populations.
When Save The Sound’s ecological restoration team removed the dam at Hyde Pond in Ledyard, Connecticut, the stream flowed into Whitford Brook, a tributary of the Mystic River, for the first time in nearly 150 years. The transformation brought fish upstream to a fishway on tribally-owned land that Woodworth says native community members built years ago in hopes of the fishes’ return.
Indigenous people have been leading the movement for river restoration across the country due to their close cultural ties to the land. On the west coast, tribes — including the Karuk, Hoopa, Yurok, Shasta, Klamath, and Modoc people — pushed for removal of Klamath’s dams since the first construction efforts began in 1903, according to scientist and writer Heather Wiedenhoft. “For a lot of folks from the river, dam removal wasn't something that we had to be convinced of,” said Leaf Hillman, a Karuk elder and ceremonial leader. That notion was ingrained in Hillman as a child when he would go out with his uncle to collect salmon for tribal ceremonies. “Our folks were harvesting fish from the early spring and through the late fall,” Hillman explains “So, our diet was heavily reliant on salmon.”
Before those dams were built, the Klamath water basin was home to the third-largest salmon run on the west coast. Salmon not only feed the surrounding tribes but are important to their identity. The origin myth of the Yurok Nation states that the spirit who created humans also created salmon.
After the final dam on the Klamath was completed in 1964, Hillman and his uncle would struggle to get enough fish as their numbers declined. “That last dam really announced the end of the spring run in the Klamath — which used to be the largest run in the Klamath,” Hillman said. “The correlation between the construction of that dam and the demise of the spring fishery was pretty clear to our tribal fishermen at that time.”
Studies commissioned by the tribe — which drew data from their healthcare records — found connections between the establishment of Iron Gate Dam and the deterioration of community health. “Diabetes never really showed up in our population until the collapse of that spring fishery,” Hillman said.
In 2002, over 34,000 Chinook salmon died of a bacterial outbreak in the Klamath. The Yurok Tribal Fisheries Program found low water flow from the Iron Gate Dam to be a contributing factor in the fish’s death, since the stagnated flow resulted in a delayed migration where the fish ended up crowded in warm waters, providing the perfect environment for disease to spread.
That die-off energized the community to campaign harder for dam removals. Hillman and other river activists had begun protesting at the offices of PacifiCorp, a major power company that owned the dams. Their battle led them to Scotland to talk with the then-owners of PacifiCorp. “Even when negotiations failed and everybody walked away from the table unable to move forward, it was always the tribes who revitalized the process,” Hillman said. He credits their perseverance to the fact that many Indigenous people have never considered the possibility of moving away from their land, and thus it was always important to continue fighting for the river that is their lifeblood.
Since the dismantling of the Klamath dams, salmon have bounced back in ways that exceeded expectations of local biologists. “It’s pretty exciting to see fish almost immediately go past the dam sites,” said Toz Soto, the fisheries program manager for the Karuk Tribe. The Chinook salmon population is estimated to increase to appromixately 81% of its previous population by 2061. About a month after the final dam’s removal, a Chinook was spotted in the Oregon portion of the basin — an area where they haven’t been seen for over a century. “This dam has been basically a cement wall where fish have been banging their heads … it's in their genes and in their instincts to distribute upstream,” Soto said.
But dams don’t just deplete food sources and cause community displacement. They also degrade a river’s terrain. “One of the reasons why dams are so bad is because they stop sediment from moving through a watershed into lower reaches,” said Woodworth, who’s trained in fluvial geomorphology — the study of the forces that shape rivers. Though many view sediment as a pollutant, it actually improves the ecology of a river.
All of this begs the question: Should we invest in rebuilding destroyed or decaying dams, or should we let the rivers restore themselves to their natural states? There are million-dollar plans in place to reconstruct the dams at Mill Pond and Stump Pond. In September, I emailed Suffolk County Executive Ed Romaine’s office to ask if he is taking into consideration the growing push for dam removals in his decision to rebuild. A spokesperson didn’t address my questions, but did reply that “County Executive Romaine is working with the DEC to obtain permits to rebuild the dam. The lake has been part of the community for more than 200 years and plays an integral part in the county’s nationally-recognized parks system.” Consequences be damned.
