America thrived by choking its rivers with dams. Now it’s time to undo the damage.

The country must decide the fate of more than 90,000 dams, many of which are in disrepair.

The fish is nearly three feet long, and as it swims unhurriedly past the viewing window in Lower Granite Dam, Theresa Wilson glances up from her knitting. “Chinook,” she says, tapping her computer keyboard once to record its passage. The salmon pauses as if to be admired. Its mottled scales flash as it moves against the current of the Snake River. Then it darts away, bound upstream to the place where it was born.

Salmon and trout are anadromous: They hatch in rivers, spend their lives at sea, then return to their birthplaces to reproduce and die. Here on the Snake in eastern Washington, that means traversing four hydroelectric dams, an arduous undertaking few complete.

The Lower Granite is the last barrier between this chinook and its spawning grounds. It is one of 13 salmon and trout species in the Pacific Northwest that the federal government lists as threatened or endangered. The concrete and steel structure in its way stands 151 feet tall and spans a gorge, its turbines sending froth churning downstream. Clearing the wall requires that a swimmer ascend a spiral structure called a fish ladder to a resting pool, where a viewing portal lets Wilson keep track of them for University of Washington biologists and others monitoring the impact dams have on piscine populations.

According to legend, the Snake brimmed with so many fish when the explorers Lewis and Clark arrived in 1805 that one could walk from bank to bank on their backs. Today the animals pass so rarely that Wilson spends much of her eight-hour shift making socks.

As recently as the middle of the 20th century, nearly 130,000 adult chinook returned to these waters in a single year. Around 10,000 made the journey in 2017, a dip that threatens the health of the river and all it sustains. More than 130 species of insects, birds, fish, and mammals—from bears in the Teton Range to orcas in the Pacific—rely on salmon for food. Even plants and trees benefit, drawing nutrients from their waste and remains.

Across the nation, the scenario repeats. Atlantic sturgeon, once a hallmark of the eastern seaboard, can reach only about half of their historic spawning grounds. Some 40 percent of the 800 or so varieties of freshwater fish in the US, and more than two-thirds of native mussels, are rare or endangered, in part because man-made barriers have altered their ecosystems. Reservoirs disrupt currents, altering water’s velocity and temperature. That can harm its quality and interrupt the reproductive cycles of aquatic creatures. Stanching a river stops the distribution of sediment and the formation of logjams, two things critical to creating healthy habitat. It also eliminates floodplains and natural meanders, both of which prevent the banks from overflowing.

America was shaped by its rivers—more than 250,000 in all—and since Colonial times we have bent them to our will. The Army Corps of Engineers, which oversees dams owned by the federal government, lists more than 90,000 in its national inventory. Tens of thousands more remain unregistered. “Think about that number,” then-Secretary of the Interior Bruce Babbitt told a meeting of the Ecological Society of America in 1998. “That means we have been building, on average, one large dam a day, every single day, since the Declaration of Independence.” The best of them generate power, facilitate navigation, and slake our thirst. But many, perhaps the majority, are no longer essential.

The falling cost of renewable energy and continued decline of manufacturing renders many of these structures unnecessary. Others require expensive maintenance. Seven in 10 are more than 50 years old and many are falling into disrepair, according to the American Society of Civil Engineers, which pegs the cost of upgrading the 17 percent it deems a “high hazard” (meaning a failure could kill people downstream) at $45 billion. Overhauling the rest will cost many times that. In response, a growing number of scientists and environmentalists have called for razing dams that are obsolete or dispensable and letting more rivers—nature’s original infrastructure—once again run free.

Many of those advocates consider the Elwha River 50 miles west of Seattle a model. Salmon and trout had all but vanished before the National Park Service breached two dams there in 2014, reviving the waterway and surrounding wilderness with little effect on power supplies. Restoration champions believe the same will happen on the Snake, where they’ve waged a decades-long fight against the Corps, regional politicians, and farmers who argue that the hydroelectric power it generates remains essential and that knocking the system down might not save the animals.

As pressure mounts to “free the Snake,” the Corps and others are considering similar projects nationwide, a trend that could reshape what Duke University hydrologist Martin Doyle calls “our riverine republic.”

“We’re shifting our priorities, and we’re left with this relic landscape that’s no longer applicable,” he says. “Where that legacy infrastructure gets in the way or causes problems, let’s undo it. The future of 80 percent of dams is very questionable, or should be.”

River dam puzzle
“The future of 80 percent of dams is very questionable, or should be.” – Hydrologist Martin Doyle Brian Klutch

The snake meanders 937 miles from its headwaters in Yellowstone National Park through Idaho (where it remains one of the most unspoiled aquatic habitats in the West) and into Washington. There, it wends another 141 miles across a region called the Palouse—5 million acres of otherworldly dunes and golden wheat fields—before joining the mighty Columbia River.

Bryan Jones grew up here, near a town called Dusty, on land his great-grandfather settled a century-and-a-half ago. The family has always grown wheat, and their farm now covers 640 acres. In a good year, Jones will harvest 18,000 bushels. Washington is the country’s fourth-largest producer of the crop, which we mostly export.

The Army Corps of Engineers built four hydroelectric dams here on the lower Snake River between 1961 and 1975, deepening and widening the channel to accommodate barges headed to Portland, Oregon. “I think we were sold the promise of this new way to ship our grain, and we thought that was a good thing,” Jones says. For years, boats provided a cheaper alternative to trucks and trains. But the locks at Ice Harbor, Lower Monumental, Little Goose, and Lower Granite dams weren’t the boon many expected, and barging declined as costs rose. Today, less than 3 million tons head downriver each year, a decrease of 26 percent from the industry’s heyday in 2000.

Jones is the rare farmer who favors razing the structures. He can make an economic argument—he believes transport over land makes more financial sense—but at the heart of his opinion lies something simpler: He misses the landscape of his childhood. “All up and down the Snake River there were sandy beaches, and orchards in the riparian area,” he says. “I can remember my grandmother having a table out here in the yard full of boxes and boxes and boxes of peaches. Everything from tomatoes and green beans, and beets and beans. There were melons, alfalfa fields.” He also recalls the abundant wildlife. Much of it is gone now, flooded by the reservoirs between the dams, he says.

So too are most of the fish. All four salmon and steelhead species found in the Snake are classified as threatened or endangered—a trend seen throughout the Pacific Northwest, where the US government manages 31 dams. Their decline prompted President Jimmy Carter to sign a law in 1980 authorizing Idaho, Montana, Oregon, and Washington to develop a plan for saving them. The Bonneville Power Administration, a federal nonprofit that sells electricity generated by the dams, has spent an average of $220 million per year on habitat restoration and hatcheries since 2007. It has also given an average of $77 million annually to the Corps and other agencies, helping finance what Corps spokesman Joe Saxon calls “the world’s most advanced fish passage systems.” Spillway weirs and ladders, both of which resemble water-park slides, help guide the animals over each dam. Workers pump small juveniles, called smolts, out of collection pools and into trucks and barges that carry them downriver. Cooling systems maintain reservoir temperatures to protect the creatures. Saxon says more than 99 percent of adults and 95 to 100 percent of youngsters survive the trip past the structures.

But those numbers reveal only part of the picture. Critics often characterize such claims as “akin to dropping a goldfish from a 100-floor skyscraper, seeing it is still alive at floor 75, and concluding it’s OK,” says Helen Neville, head scientist at the advocacy organization Trout Unlimited. Dams and reservoirs tax migratory fish by altering their route to and from the sea. This is especially hazardous for smolts. Rather than riding a swift, cold current downstream, they spend time and energy navigating the warmer, slower water of a reservoir, where they face greater odds of becoming something’s dinner. Should they escape unscathed, a 2014 study by the US Fish and Wildlife Service found that reaching the ocean takes youngsters an average of two weeks longer than it did before the dams went up. The same analysis shows the added stress kills nearly 1 in 4 migrating fish. Those that live to see the Pacific face threats there too, of course. All told, in recent years, fewer than 1 percent of juveniles that made it to the ocean have returned upstream to spawn. Before the Corps built all that hydroelectric infrastructure, the rate was 6 percent; biologists consider 2 percent sufficient to maintain a sustainable population. “They are truly straddling extinction,” Neville says.

That prompted 55 scientists from throughout the US to sign a letter in October 2019 calling for the demolition of the structures. They base their plea on five federal court rulings since 1994 directing dam and waterway managers to consider additional measures to protect the wildlife and take a closer look at removal. (The Fish Passage Center, funded by Bonneville Power to monitor piscine populations, has said breaching could quadruple the number of salmon returning to spawn.) The agencies involved must complete a court-ordered environmental-impact study—the latest of many—in 2020, but it probably won’t end the debate. Many farmers, fearing a rail monopoly, don’t want to lose the barges, and some regional politicians join the Corps in arguing against doing away with an energy source that, running at full-tilt, could power a city the size of Seattle. Currently, though, the dams provide just 4.3 percent of the region’s power.

Dismantling the structures might be the most cost-effective option. Each of the 24 turbines in the lower Snake system has exceeded its 50-year life span. The Corps signed a $115 million contract in 2016 to install three at Ice Harbor Dam. Meanwhile, the region’s hydropower prices have climbed 30 percent since 2008, making Bonneville Power electricity more expensive than juice from other sources. A 2018 study by the NW Energy Coalition, an alliance of 100 public and private entities, found that solar, wind, and natural-gas generation could provide the same backup reserve, and building the needed infrastructure would add just $2 to customers’ monthly utility bills.

Political will for removal appears to be intensifying. In April 2019, US Rep. Mike Simpson of Idaho called for a serious look at it, and Washington Gov. Jay Inslee signed legislation allocating $750,000 to study how best to assist communities that would be affected by the dams’ elimination.

In addition to the threat posed by dams, anadromous fish face an existential threat from climate change. In 2015, high water temperatures killed 96 percent of the Snake’s returning sockeye salmon. But those who favor breaching the barriers agree that unleashing the river will cool the water, create more spawning habitat, and give the imperiled creatures better odds of survival. And that, they say, can only help the Snake overall. “I hope those dams come down,” Jones says. “I’d love to see it in my lifetime. Every species that can get to the river and catch a fish is going to thrive.”

Mike McHenry’s soggy Belgian Malinois, Ginger, stands at the edge of the Elwha River in western Washington, whining softly. He holds her back from a pool where hundreds, perhaps thousands, of tiny salmon fry shimmer in the sunlight. They are just a few months old, and before long, they will begin their journey to the sea. McHenry releases the dog, and she bounds into the water. The wee fish scatter.

McHenry has spent more than three decades as a biologist and habitat manager with the Lower Elwha Klallam Tribe. Their ancestral land has been radically reshaped since the removal of two hydroelectric dams allowed the river to run unfettered for the first time in more than a century.

The waterway begins in a snowfield high in the Olympic Mountains and flows 45 miles north to the Strait of Juan de Fuca. For millennia, the river ran thick with salmon and trout. As many as 400,000 adult chinook, coho, and other species returned annually to spawn, making it one of the richest anadromous fish habitats in the nation.

That changed in 1910, when the Olympic Power Company erected the Elwha Dam to power timber and pulp mills in nearby Port Angeles. In 1927, it built another, called Glines Canyon, 8 miles upstream of the first. Beyond flooding Klallam religious sites and a verdant floodplain, the structures, which lacked fish passages, reduced spawning grounds to the river’s first 5 miles. Salmon populations plummeted in response. During the 20th century’s waning years, the system produced a negligible amount of electricity—​about half the energy requirements of a single local mill—and its owners had decided that making it more fish-friendly was too expensive. In 1992, President George H.W. Bush signed a bill authorizing the Interior Department to buy the dams for $29.5 million, tear them down, and restore the habitat.

The National Park Service spent almost two decades planning the $350 million project. The biggest challenge was managing the immense amount of sediment: Some 33 million tons of silt, gravel, and rock littered the two reservoirs. A free-flowing river moves a lot of earth; letting it all go at once would wreak havoc downstream. Work started in 2008 with construction of a treatment plant to filter the Port Angeles water supply. Beginning in 2011, crews partially drained the lakes and slowly emptied them by dismantling the barriers in 10- to 20-foot sections using a crane and a barge-​mounted excavator. The final chunks of concrete and steel fell in 2014.

That done, the Park Service worked with the tribe on the agency’s second-​​largest habitat-​​restoration project ever. Biologists, botanists, and volunteers planted tens of thousands of indigenous trees, grasses, and other plants on floodplains denuded by the reservoirs. Salmon and trout ventured upstream within months. Still, officials augmented their meager numbers with animals raised in hatcheries. Although the water remained cloudy for more than two years, the dirt and gravel eventually settled, creating sandbars, beaches, and a vast estuary at the river’s mouth near Port Angeles.

Researchers snorkeling the length of the Elwha in 2018 counted 15,000 steelhead trout, about twice as many as a decade before. Otters have followed the fish upstream. Birds and large fauna like deer and bears, which had dwindled alongside anadromous species, have reappeared in unprecedented numbers. The floodplain, rejuvenated by all that nutrient-rich sediment and new growth, teems with life, and logjams—​some created by the river, others by McHenry and his team—​provide refuge for smolts. He points out elk droppings among the alder trees, and a salmon carcass hauled ashore by a predator.

Removing the dams inarguably revitalized this riparian zone. Restoring the habitat, McHenry says, did more than save the fish. It also created a natural defense against flooding, opened the river to greater recreational opportunities (federal and tribal officials will consider allowing salmon fishing in 2021), and resurrected woodlands and shorefront. “Damming a river’s about the most egregious thing you can do if you want to mess it up,” he says. “You can argue there are services you get out of that. But at least in this part of the world, and, I guess, in my value system, I think the services a wild river offers way exceed damming it.”

https://www.youtube.com/watch?v=VipVo8zPH0U

For more than a century after it was dammed, the Elwha met the sea at a rough cobble shoreline. Today the free-running river has created a wide beach of fine, ashy sand dotted with shrubs that provides habitat for shellfish, beavers, shorebirds, and other creatures. None of the computer models the federal government ran before the project predicted this. “About 3.5 million cubic yards of sediment were plopped here,” McHenry says, “and now we have an estuary ecosystem where there wasn’t one before.”

Not only can young fish make the transition from fresh to salt water, the estuary attracted enough Dungeness crab to support a robust fishery. Just offshore, a long line of floats marking the location of traps runs parallel to the beach. The operation provided an unexpected economic boost.

Of the 1,605 dams toppled nationwide since 1912, the two on the Elwha remain the largest, according to the advocacy organization American Rivers. Some 1,200 have come down in 46 states and the District of Columbia in the two decades after the Interior Department’s Babbitt, who led the agency under President Bill Clinton, made river restoration a priority. In 1999, the Edwards Dam in Augusta, Maine, became the first major hydroelectric dam razed by the federal government. The structure, built in 1837 to power bygone grain mills along the Kennebec River, nearly killed off the herring, striped bass, and sturgeon. Today the waterway draws sport fishers, and the city gained a popular riverfront district with a park, pavilion, and kayak and canoe launch.

To keep the momentum going, American Rivers is working with public agencies and private organizations to bring down dozens more dams throughout New England, and restore riparian habitats across the nation. Meanwhile, the Army Corps of Engineers is considering the future of two dams at St. Anthony Falls, where the Mississippi River flows through Minneapolis. Authorities hope to breach four others on the Klamath River in Northern California within the next few years, a move that would reclaim 300 miles of salmon-spawning habitat.

Major projects like that attract a lot of attention, but the cumulative impact of many more-​modest removal plans could yield equally profound ecological and economic dividends. “You can get a lot of species recovery and some very diverse ecosystem recovery with much-smaller sledgehammers,” Doyle, the Duke University hydrologist, says. Now that the usefulness of these man-made barriers has run its course, it is time to let the rivers they restrain return to theirs.

This story appears in the Spring 2020, Origins issue of Popular Science.