By Scott Smith, Communications Director
Americans are really good at building dams. Too good, in fact. Now, the looming question is, can we get just as good at removing those dams that are obsolete, hazardous to humans or ruinous to the environment and wildlife? There’s growing evidence that we can—and must.
In July, the Biden administration released two reports on the feasibility of removing four dams on the lower Snake River in the Columbia River basin. As reported by The New York Times, 13 species of salmon and steelhead trout are listed as threatened or endangered in the Columbia River basin, an area that includes parts of Idaho, Oregon, Washington, Montana and British Columbia. “The salmon are critical to the ecosystem of the river basin, serving as a food source for animals as large as bears and as small as insects. They contribute to the survival of endangered orcas, which depend on eating Chinook in the winter and spring.”
Conducted by scientists at the National Oceanic and Atmospheric Administration, the reports found that sweeping changes are needed to restore salmon, in part by reintroducing ocean-going, river-spawning fish to breeding grounds entirely blocked by the dams.
The Times report added that “Senator Patty Murray, Democrat of Washington, who long resisted any salmon recovery plan that included removing the four dams, joined Gov. Jay Inslee of Washington, a fellow Democrat, in commissioning a separate study released this summer. That study found removing the four dams was the most promising approach to salmon recovery.”
From grist mills to the Big Dam Era
There are more than 90,000 dams in the U.S. National Inventory of Dams greater than head-height, and over 2 million smaller dams and stream barriers throughout the country. About a third are used for recreation, flood protection, irrigation or fire protection, and only a tiny fraction for hydropower.
Despite all the hype about the awesome scale of some of the biggest dams—Grand Coulee Dam on the Columbia River, for example, contains enough concrete to build a highway from Seattle to Miami—dams overall generate just 7% of total U.S. electricity. Hydropower currently accounts for about 37% of total U.S. renewable electricity generation. Given the explosive growth in wind and solar, as well as the specter of prolonged drought forcing some of the biggest power-producing dams—on Lake Powell and Lake Mead, to name two—to potentially drop off the grid, that level is expected to decline further, and soon.
On average, the age of dams across the U.S. exceeds 55 years; few dams have been built in recent years because less than 2% of our rivers remain free flowing. For wildlife and biodiversity, that’s a critical point: Although freshwater makes up less than 3% of Earth’s water supply, the world’s streams, creeks, rivers and lakes are home to almost half of all fish species. In the U.S., river systems altered by dams and other barriers have led to 40% of America’s fish species being listed as imperiled. As a result, monitored populations of migratory freshwater fish have declined an average of 76% between 1970 and 2016.
The first U.S. dams were constructed in the colonial period to aid navigation, to provide power for grist mills and, over time, fuel the fledgling textile and steel factories that made America a manufacturing powerhouse. The Depression sparked the Big Dam Era, as the New Deal’s Public Works Administration brought multiple large-scale dam projects to realization. In the Pacific Northwest, the massive Grand Coulee Dam on the Columbia River, constructed between 1933 and 1942, provided power for the aluminum and aircraft factories that helped turn the tide in World War II.
The dam building boom continued into the postwar era. Chief among them was the 710-foot-tall Glen Canyon dam across the Colorado River, built by the U.S. Bureau of Reclamation from 1956 to 1966, which brought power and water to the desert Southwest.
Problem is, these massive engineering projects drove the rapid growth to an extent that is far above what the region can support, argues Giuliano Di Baldassarre of the Department of Earth Sciences at Uppsala University, Sweden, in a 2021 case study about the legacy of large dams in the U.S. As dam development has plateaued, water wells are getting deeper and groundwater levels are declining. Meanwhile, drought exposure has increased because of population growth and agricultural expansion.
However, there is some good news. Efforts to take down outmoded dams and restoring critical habitat are now paying off where U.S. dams first rose—on the rivers along New England’s historic mill towns.
The removal of the Edwards Dam on the Kennebec River in Maine, in 1999, marked the first time the federal government determined the public benefits of a free-flowing river were greater than those provided by an existing dam. Built in 1837, the dam proved disastrous for local stocks of species like American shad, Atlantic and short-nosed sturgeon, Atlantic salmon, striped bass, American eel and river herring, once found in great abundance in tidal rivers up and down the Atlantic Seaboard.
In the past 25 years, some 1,800 dams have come down across the U.S, reports the nonprofit group American Rivers. Most are in the Northeast, though the movement is spreading. For example, in 2020, 69 dams were removed in 23 states, with Ohio leading the way with 11 and Massachusetts and New York with 6 dam removals each.
When the dam breaks
Where the political will exists, dam breaching can’t come some enough. Under threat from development, pollution and climate-change impacts, the health of the nation’s lakes, rivers, and wetlands are declining at a much faster rate than terrestrial ecosystems. The dire state of U.S. freshwater resources has prompted The Pew Charitable Trusts to engage with NatureServe and Michigan State University to build national databases of watershed conditions and barriers that alter the natural flow of rivers, streams, and other freshwater bodies.
“River and wetland protection and dam removal can rapidly deliver benefits, such as supporting human health and conserving species and habitats, across watersheds and well beyond the banks of the protected waterway,” writes Nicole Cordan, who oversees river protection and restoration work for The Pew Charitable Trusts. “We hope these interactive database maps will add to the growing understanding of the nation’s vital waterways and result in science-based actions that will ensure their restoration and conservation for generations to come.”
Check out the databases to see if an old dam impeding a river or stream in your area is a candidate for removal and then join your neighbors in the fight to restore free-flowing waters. True progress requires recognizing when you’ve made a mistake and then committing to undo it.
Let’s face it: We are now forced to reverse any number of so-called advancements once hailed as proof of American ingenuity. Cars powered by internal combustion engines (and fueled by leaded gasoline) are giving way to electric vehicles; fire-retardant asbestos, known to have deadly health effects since the early 1900s, is finally being mitigated; synthetic pesticides, from the DDT of Rachel Carson’s day to today’s insidious neonicotinoids, are slowly being replaced by organic treatments and integrated pest management.
And one by one, those damnable dams are being breached. Good riddance!