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As the Harms of Hydropower Dams Become Clearer, Some Activists Ask, ‘Is It Time to Remove Them?’
发布日期:2024-12-19 07:11:22
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For most of Joey Owle’s life, the Ela Dam was merely part of the landscape—just another feature of the Oconaluftee River as it runs through Whittier, North Carolina.

Owle grew up about five miles from the dam in the Qualla Boundary, the tribal territory of the Eastern Band of Cherokee Indians about 60 miles west of Asheville. For some tribal members, he said, the dam provided a good spot to catch Sicklefin Redhorse, an olive and copper colored river fish with a pronounced dorsal fin that gathers at the basin beneath Ela’s spillway each spring.

“In Cherokee, we call it U-gi-da-tli,” Owle said, “which means, ‘It wears a feather,’ because of its dorsal fin.”

But in October of 2021, Ela Dam became more than a benign fishing hole for Owle and other Cherokee members. While working on a malfunctioning mechanism of the floodgate, dam operators accidentally unleashed a wave of sediment downstream. According to state officials, the event buried important aquatic habitat for the Sicklefin Redhorse and several other sensitive species under 18 to 24 inches of silt and sand. The dam’s owner hired a contractor to remove the sediment, but federal scientists fear the incident could have caused those species irreparable, long-term harm.

The accident didn’t surprise Patrick Hunter, an environmental lawyer with the Southern Environmental Law Center. The United States is home to more than 90,000 dams that serve a variety of purposes, including to prevent flooding, expand development, provide water for irrigation or generate electricity—like Ela.

But more than half of those dams were constructed decades ago, Hunter said, and many of them are now in poor condition. “A lot of dams in our country are quite old,” he said. “And many of them are like Ela Dam, which was built in 1925, where they’re arguably getting toward the end of their useful life and they’re in need of repair.”

In fact, over half of the nation’s dams are now more than 50 years old, according to Stanford University’s National Performance of Dams Program. That report counted more than 1,000 dam failures across the country over the last five decades, resulting in dozens of deaths. And a two-year investigation by the Associated Press, published in 2019, identified at least 1,680 U.S. dams in “poor” or “unsatisfactory” condition that currently pose a risk to humans.

Evidence also suggests the dangers posed by dams will only get worse as the climate warms. Experts, including scientists who worked on the federal government’s National Climate Assessment, have warned that many U.S. dams weren’t built to withstand the increasingly intense and frequent rainfall and flooding being driven by rising temperatures. That conclusion appears to be supported by data kept by the Association of State Dam Safety Officials. An analysis of that database, last updated in February, found the vast majority of the nation’s dam failures between 2010 and 2019 occurred because there was simply too much water for the dams to handle. 

That’s what happened in 2015 and 2016, when heavy rain caused more than 70 dam failures in South Carolina. It happened in 2018, when Nebraska’s 92-year-old Spencer Dam unleashed a torrent of water and ice in the wake of a historic late-winter storm, washing away at least one home and killing a man who lived there. And again in 2020, when a spring downpour caused two century-old dams in Michigan to collapse, causing record flooding and forcing thousands of people to evacuate.

The failure at Ela Dam was nowhere near as catastrophic. Still, it galvanized 34-year-old Owle, who works as the Cherokee tribe’s secretary of agriculture and natural resources, to search for ways to prevent another accident. Long before Owle’s time, a thriving population of Sicklefin Redhorse played a central role in the Cherokee diet and tradition. Like salmon, Redhorse swim upstream to breed. And since the dam’s construction in 1925, the fish’s population has plummeted. North Carolina now considers it a threatened species. 

For years, Owle had dreamt of getting rid of the Ela Dam entirely and restoring a once cherished Cherokee fishery. But removal never seemed like a real possibility. Then in November 2021, just a month after Ela’s sediment release, Congress passed the Bipartisan Infrastructure Law. The $1.2 trillion bill included $200 million for the National Fish Passage Program, which explicitly funds dam removals and other projects that can improve fish migration and mitigate flood threats.

Suddenly, Owle’s dream didn’t seem so far-fetched.

Joey Owle, left, and Erin McCombs, middle, at Ela Dam. Credit: Molly Phillips

Only two years prior to the accident, Northbrook Carolina Hydro II, a subsidiary of the Arizona-based hydropower operator Northbrook Energy, had purchased Ela Dam as part of a larger portfolio from electric utility Duke Energy. Feeling daring, Owle called up the new owner and laid out his proposal: Forget repairs, what if they worked together to remove the dam instead, using federal infrastructure money?

“What do you think about that?” Owle remembers asking.

To his surprise, the company was interested. But Owle would need to secure $10 million in federal funding to make his plan a reality.

Saving America’s ‘Most Endangered Organisms’

Erin McCombs thinks freshwater mussels are simply fascinating.

She’s captivated by their colorful names, like Appalachian Elktoe, Rabbitsfoot and Pistolgrip. She’s intrigued by their breeding habits, which involve mussel offspring hitchhiking a ride upstream inside the gills of fish. That’s not to mention, McCombs said, that freshwater mussels are also natural water purifiers, removing algae, phytoplankton and bacteria—including dangerous E. coli—from the nation’s waterways. It’s a feat that has earned the hard-shelled invertebrates the title of “the liver of the river.”

“To an everyday person who doesn’t know what a mussel is, who never wants to know what a mussel is, a mussel is helping them out and it’s making their water cleaner,” said McCombs, a biologist and river conservationist with the environmental nonprofit American Rivers who lives in Asheville. “We need them as part of our complex ecosystem.”

But freshwater mussels are in trouble.

Climate change and other human activities have decimated domestic mussel populations, perhaps even more so than other animals. In September 2021, the U.S. Fish and Wildlife Service declared 23 animal species extinct. Eight of them were freshwater mussels, found in rivers and streams across 10 different states, from Illinois to Mississippi to Virginia. The announcement prompted the Center for Biological Diversity to call freshwater mollusks, which include mussels, “the most endangered group of organisms in the United States.”

McCombs, who hoped at first glance that the eight mussel species had been removed from the federal list of endangered species because their populations recovered, took the news especially hard. “When I saw those freshwater mussels were removed from the endangered species list because they were extinct, of course I felt that deeply,” she told me during an interview in early March. “It made me really, really upset. I read about each one of those freshwater mussels.”

Federal scientists largely blamed dams for the decline of those eight extinct mussel species in Southern and Midwestern states. They said that’s because the structures physically block fish and the mussel offspring they carry from traveling upstream to complete their natural spawning cycle.

As global warming drives more frequent and intense heat waves and increases average water temperatures, scientists say the dams also obstruct freshwater wildlife from swimming upstream or downstream to more hospitable habitats. Researchers saw this situation play out in the early 2000s when a spell of severe heat led to tens of thousands of native salmon washing up dead on the banks of the Klamath River, which itself hosts five dams along the California-Oregon border. Mussels, which bind themselves to the streambed and essentially migrate through their offspring, are especially vulnerable to this kind of danger.

Ela Dam in the summer. Credit: Erin McCombs

It’s a threat that McCombs thinks about a lot, and it’s why she has worked for more than a decade to revitalize the habitats of U.S. rivers. One of the most helpful things humans can do to improve river ecosystems, she said, is to remove dams.

In December 2021, McCombs was brought into the talks over potentially removing Ela Dam from the Oconaluftee River. Her organization, American Rivers, has worked on more than 200 dam removal projects across the country, with a goal of removing a total of 30,000 by midcentury.

Still, the prospect of tearing down Ela Dam carries personal meaning for McCombs, who has watched for years as North Carolina’s Appalachian Elktoe populations fell. The endangered freshwater mussel has long relied on Sicklefin Redhorse to carry its offspring some 18 miles up the Oconaluftee toward its headwaters near the border of North Carolina and Tennessee in Great Smoky Mountains National Park.

Appalachian Elktoe and Sicklefin Redhorse have declined in tandem over the last century, largely because they can’t get past Ela Dam. But McCombs believes if they can remove it, there’s a real chance that both species can recover. “It helps me to find some grounding knowing that I’m working on something that feels really important,” she said. “If we can avoid the loss of another species because we’re able to reconnect some habitat, that’s huge.”

Hydropower Faces an Inflection Point

Scientists first started documenting the methane emissions of reservoirs around 1998, if John Harrison’s memory serves him correctly. He even remembers witnessing the phenomenon himself at a reservoir near Washington State University Vancouver, where he teaches.

“We would see the whole thing bubbling,” he said, “like somebody’s taking the top off a bottle of Coca-Cola—just fizzing.”

That was around 2012, Harrison said, when he first saw methane gas rising from the depths of Lacamas Lake, a 140-year-old reservoir that sits just northeast of Portland near the Washington-Oregon border. The potent greenhouse gas, roughly 80 times more effective at warming the climate than carbon dioxide over a 20-year timeframe, often forms at the bottom of lakes and reservoirs as organic matter like plants or dead animals decompose. Some of that methane also converts into carbon dioxide. 

But Harrison, who has studied dam reservoirs for decades and is now one of the world’s leading experts on their emissions, said most people aren’t even aware that hydropower operations regularly emit climate-warming gasses—let alone at levels that should concern the public.

In 2021, Harrison led a team of researchers whose study found that the world’s reservoirs—more than 1 million in total—produce the equivalent of 1.07 gigatons of carbon dioxide emissions every single year, or about the annual emissions of the entire country of Germany. In fact, the research, which was published in Global Biogeochemical Cycles, showed that global reservoir emissions are about 29 percent higher than suggested in previous studies—an oversight largely attributed to failing to account for rogue methane gas that escapes downstream before bubbling to the surface.

Harrison’s research also suggested that reservoirs produce more methane than natural lakes. That’s because the rivers carry organic matter downstream, where it piles up at the dam and decays in large quantities, producing both methane and CO2. Additionally, reservoirs are typically closer to human activity than lakes. Therefore, they’re more likely to receive waste and various runoff from agricultural or other industrial operations. That runoff can contain fertilizer, sewage and other matter high in phosphorus and nitrogen—key nutrients that fuel the creation of methane gas.

Those findings, along with others from dozens of studies that drew similar conclusions, add to a growing body of evidence that suggest hydropower may not be the source of clean energy people once thought it to be. Yet that knowledge, he said, isn’t making its way into mainstream conversations, even as public outcry over climate change reaches historic heights and policymakers craft ambitious plans to slash their countries’ emissions.

“Over the last couple decades, we’ve gained a much better understanding of the fact that these systems are consistently sources of methane to the atmosphere,” Harrison said. “But I still hear from people locally that hydropower is a carbon neutral source of energy or that there’s no greenhouse gas liability associated with hydropower.”

Other research, like this 2016 study published in Environmental Research Letters and another 2016 study published in PLOS ONE, found that the greenhouse gas emissions produced from many hydroelectric dams—such as Nevada’s iconic Hoover Dam—can even rival the emissions generated by fossil fuel power plants.

Gary Wockner, a longtime environmental activist who has dedicated years of his life to raising awareness about reservoir emissions, said that those 2016 studies jump-started a larger global conversation about what role—if any—hydropower should play in the clean energy transition. But that was also the year President Donald Trump was elected into office, Wockner said, and Trump’s deregulatory agenda forced many activists to shift their focus to maintaining current environmental protections rather than pursuing new ones. “So, the whole fight became very different,” he said. “It was about fossil fuels again.”

Wockner now believes that conversation is starting to break through.

In 2019, the Intergovernmental Panel on Climate Change, the United Nations’ body responsible for synthesizing the landmark climate reports that form the foundation of the Paris Agreement, adopted new standards regarding reservoir emissions that more accurately account for hydropower’s production of methane. Last year, the U.S. reported its reservoir emissions to the U.N. for the first time, though it used less stringent standards than those recommended by the IPCC.

Wockner’s organization, Save the Colorado—along with the environmental nonprofit EarthJustice, the outdoor apparel company Patagonia and other green groups—have also petitioned the Environmental Protection Agency to start requiring hydropower operators to report their annual emissions to the government, just as any coal or natural gas power plant owner is required to do. The EPA has yet to respond to the petition, but the agency is now pursuing the most comprehensive national study of reservoir emissions to date.

In fact, around the world, conversations about dams—and especially proposals to build new ones—are receiving pushback in ways that activists like Wockner say they’ve never seen before. Proposals to build new dams in Canada and send their electricity to New York have split the environmental community in recent years, forcing government officials to weigh the environmental and social justice costs of building dams against the need to meet tough climate goals. And notable movements opposing dam projects have sprung up over the last decade in countries like the Philippines, Honduras and Myanmar, led largely by Indigenous communities.

Dam removals are also gaining momentum. In the American West, work to remove four dams on California’s Klamath River has already begun. It’s the largest and most expensive project of its kind in U.S. history.

Patrick Hunter, the environmental attorney with the Southern Environmental Law Center, believes U.S. dams are now facing an inflection point. “Dams are getting older and becoming more expensive to maintain,” he said. “And at the same time, many of these licenses that were issued decades ago are starting to run their course, so dam owners are going to be faced with some decisions about what to do.”

The Hunt for Funding

Things moved quickly after Joey Owle’s initial phone call with Northbrook Carolina, Ela Dam’s new owners. 

By early 2022, Owle was leading a coalition consisting of the Eastern Band of Cherokee Indians, Northbrook Carolina and several environmental nonprofits, including Erin McCombs’ American Rivers. Working together with state and government agencies, they crafted a plan to study the options and costs of removing Ela Dam. And by the end of 2022, the coalition had even obtained an $800,000 grant from the North Carolina Wildlife Resources Commission to fund the planning efforts.

Hunter, who has been providing technical and legal advice to the coalition members, was pleasantly surprised by how smooth the whole process has been. “In my experience, this is pretty uncommon for all of these groups to be working side by side like this,” he said. “I think that’s part of what makes this project really special.”

A Fish and Wildlife Service official holds a Sicklefin Redhorse. Credit: ESM

If all goes according to plan, the ownership of Ela Dam would be given to Mainspring Conservation Trust, a nonprofit land trust, and the dam’s removal would wrap up sometime in 2024, reconnecting 549 miles of stream and turning the Oconaluftee into a free-flowing river for the first time in nearly a century.

In late March, Owle told me that everyone was ready to move forward with removal efforts as soon as they heard back from the Fish and Wildlife Service. The coalition had submitted its application in February, asking for $10 million from the National Fish Passage Program. “We’re kind of in the homestretch of finding out about our funding, sometime in April,” he said. “It’s a full court press right now.”

It would be another three weeks before Owle or McCombs heard back from Fish and Wildlife Service officials about their funding. On April 21, the agency announced it was awarding $35 million to support 39 river restoration projects across 22 states, including several that will remove dams. Those projects include the Talbot Mills Dam in Massachusetts, the Steamboat Rock and Forest City dams in Iowa, the Fern Ridge Dam in Oregon, five separate dams in Indiana and both of the E.R. Collins dams in New Jersey. Owle’s coalition would receive $4 million from that funding pool to remove Ela Dam. It was the largest grant awarded to any of the applicants, but less than half of what Owle’s group had asked for.

The coalition now has until July to secure the rest of the funding. After that, Northbrook Carolina could end up pulling out of the proposal. The company’s contract to sell Ela Dam’s electricity—just shy of 1 megawatt of capacity—to Duke Energy is nearing its end and would need to be revisited if removal is off the table. The company could also be losing money if details to decommission the dam and relinquish ownership aren’t nailed down soon, according to Bryan Tompkins, a staffer with Fish and Wildlife Service who has been helping to coordinate the removal efforts.

“The longer this thing draws out, they’re likely spending more and more money,” Tompkins said of Northbrook Carolina. “And they’re rolling the dice on all these other things as well—the power purchase agreement, repairs.”

Owle remains optimistic and is already in talks with different federal and state agencies about other potential funding sources. “Thinking about the pace of the project and all that we’ve accomplished in a short 18 months, I’ll take that,” he said. “That’s a huge win: to go from just a phone call to a grant application and then to be awarded $4 million.”

McCombs feels hopeful, too. In fact, she recently bought a new wetsuit to start studying Appalachian Elktoe in the river as soon as the dam comes down. During a phone call in late April, McCombs told me that thousands of Sicklefin Redhorse are gathering at the basin of Ela Dam “as we speak,” with many of them carrying the freshwater mussel’s offspring.

“This is their spring migration, it’s normal behavior for them,” she said. “And if the Ela Dam wasn’t there, they would be all the way up the Oconaluftee River, all the way up Soco Creek, all the way up Raven Fork, and that is closer now than ever. And so I’m really excited for that.”

Corrections: An earlier version of this article incorrectly stated that the federal government now considers the Sicklefin Redhorse a threatened species. The Sicklefin Redhorse is considered a threatened species by the state of North Carolina, not the federal government. It also incorrectly stated the annual electricity production of Ela Dam, which has 1 megawatt of generation capacity.

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