Removing a Dam Can Be a Net Win for the Planet

Once hailed as clean power sources, dams are sometimes more costly to maintain than they are to tear down

The Lake Mills reservoir gets drawn down in March 2012 as part of the Elwha River Restoration, which involved the largest dam removal project in U.S. history. Joel Rogers/Corbis

Once trumpeted as river-taming, energy-producing feats of engineering, America’s dams have become the subject of introspection and, in a growing number of cases, demolition.

The country spent millions to erect an estimated 80,000 of these concrete walls across rivers all over the country, but now a variety of interest groups are rallying to remove many of them, even if it happens at great cost.

“Everything has a life,” says Rupak Thapaliya, national coordinator of the Hydropower Reform Coalition, an organization that advocates for building better hydroelectric dams and removing poor performers. “We are starting to see some hydropower dams being decommissioned, and much of it is because of economics.”

For dams that produce little power compared with newer technologies, updating their aging infrastructure would cost more than removing it.   

Seventy-two dams were demolished last year to open up more than 700 miles of streams, according to American Rivers, which advocates for the removal of certain dams to restore natural flows.

Americans have been building dams to harness rivers for energy production, irrigation, flood control and water storage since the late 1800s. To fuel a growing appetite for electricity, dam building reached a crescendo around World War II. At the time, hydropower provided three-quarters of the West’s electricity and one-third of the country’s, according to the U.S. Bureau of Reclamation.

But its grip on the country’s power grid has slipped amid competing energy sources, and today hydropower provides just one-tenth of the country’s electricity.

In the process of storing water to produce energy, dams can turn whitewater rapids into tepid reservoirs and make stretches of river unreachable to the fish that once filled them. So while economics are driving many of today’s dam removals, stricter environmental regulations also are behind the wheel.

Interactive: Before and After a Dam Removal
Illustration by Maya Wei-Haas; large tree image from VectorOpenStock, CC 2.0; text by Whitney Pipkin

The environmental rules for what constitutes a “good” dam have changed dramatically since some of the earliest dams were built.

The Endangered Species and Clean Water acts of the 1970s and the Electric Consumers Protection Act of the '80s have implications for how dams must consider fish species, water quality and “non-power values” such as recreation in their operations. For these reasons, local stakeholders see a dam’s relicensing process as “a once-in-a-lifetime opportunity to improve conditions on the river,” says Thapaliya.

Take the Condit Dam on Washington’s White Salmon River. As the hydropower project neared its 100th birthday, the dam’s generator was producing an average of 10 megawatts per hour—a mere trickle compared to the thousands of megawatts that newer projects along the Columbia River produce.

“It was going to be like $60 million to bring it up to modern environmental standards,” says Thomas O’Keefe, Pacific Northwest stewardship director for American Whitewater, which lobbies for unfettered whitewater rivers for recreation.

The dam would have to create a passage for fish and reduce its impact on water temperatures and flows downstream that affect fish spawning. Removing the dam altogether would cost the owner, PacifiCorp, about half as much as bringing it up to code.

So in October 2011, the company began with a blast of dynamite the painstaking process of removing the dam and restoring the river in its wake. A year later, O’Keefe and a celebratory contingent kayaked the length of the river that had been blocked by the dam, as recorded in the documentary film DamNation.

The following spring, a few steelhead salmon made their way past the former dam site to spawn in reaches of the river they hadn’t accessed in almost a century, while Chinook salmon laid their eggs in the new layer of gravel released by the dam removal. This spring, the number of spawning steelheads above the former dam site reached 55, O’Keefe says.

Similar stories of dam destruction and regeneration are occurring throughout the Pacific Northwest, where regional power grids built on the backs of powerful rivers are being revisited.

Now, Washington—the state with more hydropower projects than any other—is the stage for high profile dam removals that are bringing the federal fishing rights of Native American tribes, among other factors, to bear on aging infrastructure. The world’s largest dam removal took place along the once salmon-rich Elwha River last year, opening up a river closed to fish passage for a century.

Though the country’s appetite for hydropower might be waning, its energy portfolio will continue to include dams that produce enough energy to justify their presence, especially if their impacts on fish and other factors are moderated, says Thapaliya. Dams that already exist but don’t include hydropower could begin producing energy in the coming years, and others could be made more efficient.

“However,” he says, “I don’t think we are going to see new hydro[power] dams built, because the good sites have already been built on. It’s just not economical to build a new dam to produce power.”

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