Calls to dismantle aging and decrepit dams are intensifying in the United States, as evidence emerges that these steadfast sources of renewable energy have the power to unleash a barrage of environment and safety hazards.
“The debate exemplifies one of the trade-offs inherent in the clean energy transition,” writes Politico. Hydropower has provided reliable, zero-carbon energy to some regions for decades, “but has also contributed to driving some species to the brink of extinction.”
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Salmon Populations at Stake
Federal scientists have called for the dismantling of four dams that collectively power around 800,000 homes as part of President Joe Biden’s pledge to restore “healthy and abundant salmon runs” in the Pacific Northwest.
Built in the 1960s and 1970s on the lower Snake River in the state of Washington, the dams have threatened local salmon populations by blocking their return to spawning habitats. Hatcheries have not been effective in bringing the numbers back, so the dams may have to be removed to restore historical spawning routes. Tribes of the Columbia River Basin, whose sustenance, livelihoods, and territories were affected by the dam projects, stand with scientists, conservationists, and some lawmakers who say power generation is not worth the detrimental effects on wildlife and water ecosystems.
The Biden administration has vowed to work with them to find a solution, and Washington state officials are also exploring the idea of dismantling dams, with Governor Jay Inslee (D) expected to allot US$7.5 million to study transportation, energy, and irrigation issues that could arise from dam removal.
But there is also strong opposition to breaching the dams. In March, two Republican Congress members introduced federal legislation to protect them.
“It’s time to recognize that salmon runs are improving at record rates thanks to our mitigation efforts and positive ocean conditions, and that the dams provide clean and reliable energy that powers our homes and businesses,” said Rep. Cathy McMorris Rodgers (R-WA), who led the legislation. “That’s something worth protecting.”
Another complication: “electric utilities say there may be no viable way to remove the dams without turning to fossil fuels,” Politico notes.
Dams in Poor Condition
More than half of the hydropower dams across the U.S. were built more than 50 years ago. As they age, they bear a risk of failure that adds an incentive to dismantle them, reports Inside Climate News.
In North Carolina, operators accidentally unleashed a wave of sediment in 2021 while working on a malfunctioning floodgate mechanism on the Ela Dam, built on the Oconaluftee River in 1925. The event buried vital aquatic habitat for Sicklefin Redhorse and several other sensitive species, and federal scientists say the damage could be irreparable, though the sediment was removed by contractors.
Since the incident, Joey Owle, agriculture and farming secretary for the nearby Eastern Band of Cherokee Indians, has led an effort to dismantle the Ela. The $1.2-trillion Bipartisan Infrastructure Law includes “$200 million allotted for the National Fish Passage Program, which explicitly funds dam removals and other projects that can improve fish migration and mitigate flood threats,” Inside Climate writes. So Owle called the dam’s newest owner and proposed they forget repairs and instead work with him on removing the dam, funded by federal infrastructure money.
“To his surprise, the company was interested,” Inside Climate says. Owle is now working to secure funding for the Ela’s removal.
Evidence suggests the dangers posed by dams will worsen as the climate warms, ICN adds. Increasing precipitation and extreme weather are set to exceed the capacity of some dams, raising safety concerns. A two-year investigation by the Associated Press identified at least 1,680 dams in the U.S. that are considered to be high hazard and in poor or unsatisfactory condition, noting that “a dam is listed as high hazard if its failure is likely to result in people being killed.” The obstructions that dams cause for wildlife can also become more of a burden as changing weather patterns stress populations.
Reservoirs of Methane
Recent research also suggests methane emissions associated with dams have been underestimated, and are contributing more significantly to climate change than previously understood.
The world’s reservoirs—more than one million in total—release the equivalent of 1.07 gigatonnes of carbon dioxide emissions annually, 29% higher than previously acknowledged, found a 2021 study led by John Harrison, a professor at Washington State University’s School of Environment. The study also suggested some reservoirs produce more methane than natural lakes because of decomposing organic matter carried from upstream, which piles up at the dam to decay.
Harrison’s research bolsters findings from dozens of other studies that drew similar conclusions, adding to a growing body of evidence that suggests “hydropower may not be the source of clean energy people once thought it to be,” Inside Climate News says.
“Most people aren’t even aware that hydropower operations regularly emit climate-warming gasses—let alone at levels that should concern the public,” Harrison said.
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