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More Dangerous Than Nuclear Power: The Floods Caused by Aging Dams [Video]

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As the U.S. and China endure record-breaking floods this spring, there is a risk that is being overlooked amidst the inundated towns, evacuations and rising waters. Dams in the U.S. boast an average age of 50 years, and the American Society of Civil Engineers continues to give the nation’s dams a D grade overall in terms of maintenance. Will it take the catastrophic collapse of a dam—like the five in the 1970s in the U.S. that killed hundreds—before the infrastructure is repaired?

The nation’s more than 80,000 dams have served us well—restraining less-than-epic floods and generating billions of kilowatt-hours of electricity for regional grids. In fact, massive dams across the western U.S., like Grand Coulee in Washington state, still provide the vast majority of "renewable" electricity in the U.S., some 7 percent. At the same time, hydropower can help balance more intermittent renewable resources, such as wind power. For example, water can be held back water to cope with "wind droughts," prolonged periods of little or no wind such as an 11 day wind drought in the Pacific Northwest earlier this year.

But these dams of legend—that helped win World War II as the poster illustrating this post implies—are old. And old dams are in danger of failure—more than 4,000 in the U.S. alone are at high risk of imminent failure, according to the Association of State Dam Safety Officials.

Editor’s note: The original broadcast incorrectly implied that the annual U.S. military budget is $60 billion. The actual figure is closer to $685 billion.


On a per kilowatt-hour basis, dams are the most dangerous source of electricity generation, followed by burning coal with its attendant mining accidents and deaths via heavily polluted air. A tsunami flood crippled Fukushima Daiichi in Japan—prompting the meltdown of three nuclear reactors that have, so far, killed no one. A series of dam failures in China in the 1970s killed more than 200,000 people. Similarly, more than 500,000 have been evacuated in central and southern China this month due to flooding and mudslides, whereas about 80,000 have been relocated due to the nuclear plant disaster in Japan.

In fact, the filling the reservoirs behind new big dams in China may have helped trigger the deadly 2008 earthquake in Sichuan Province. As a result, the Chinese government has admitted that its most massive dam—Three Gorges—has "urgent problems," ranging from "geological disaster prevention" to the ongoing relocation of millions of people.

Nevertheless, the world is embarking on a new renaissance of big dam building; just this month Brazil gave final approval to move forward with the massive Belo Monte dam in the Amazon region of Para state on the Xingu River, which will be able to produce more than 11 gigawatts of power. Meanwhile, the world’s older dams are in dire need of refurbishment, lest the floods burst their bounds.


Image: Courtesy of Bonneville Power Administration

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  1. 1. sog001 3:09 pm 06/20/2011

    Your cost comparison is off by more than an order of magnitude. The US military budget for FY 2010 was $685 billion/year (not counting supplemental and emergency appropriations for Iraq and Afghanistan), not $60 billion/year.

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  2. 2. pathologically 3:51 pm 06/20/2011

    "The tsunami flood that crippled Fukushima Daiichi in Japan–prompting the meltdown of three nuclear reactors–has so far killed no one."

    Someone really needs to copyedit this — as it stands it’s denying the tens of thousands of deaths that resulted from the tsunami.

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  3. 3. Sue Ann 3:56 pm 06/20/2011

    The tsunami did kill. The nuclear meltdown (so far) has not. Please get this corrected.

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  4. 4. blk 4:15 pm 06/20/2011

    The story indicates that most dams in the United States are more than 50 years old. But half of US nuclear reactors are more than 30 years old, and they were only licensed for 40 years. Even though the raw numbers of potential deaths from dam failures might be higher, the psychological and ecological impacts of reactor failures can be far worse. A burst dam won’t make hundreds of square miles of land unusable for decades, and cause increased cancer risks for decades later.

    There are reactors similar to those at Fukushima on the Mississippi, in Monticello and Prairie Island, MN. If the Monticello or Prairie Island reactors melt down, the river and the Gulf of Mexico could be poisoned for centuries, with untold economic and ecological consequences.

    Fifty billion dollars is a tiny fraction of the money we spent destroying Iraq’s infrastructure and then rebuilding it. One would think it a no-brainer to spend that much to fix our dam problems.

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  5. 5. Eric R. Olson 4:19 pm 06/20/2011


    Thank you for catching the error. The figure originally referred to annual military R&D spending but was incorrectly presented as total spending. We are in the process of correcting the video and will post an updated version shortly.


    Eric R. Olson
    Audio-Video Editor

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  6. 6. dbiello2 5:16 pm 06/20/2011

    Pathologically, Sue Ann, thanks for catching that grammatical infelicity. A clumsy attempt to show that the tsunami flood caused more damage than three meltdowns.

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  7. 7. Robman7 8:50 pm 06/20/2011

    Fukushima is far from contained.

    Furthermore, how does one count the increase in cancers over the decades?

    Apples to Oranges.

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  8. 8. jtdwyer 11:25 pm 06/20/2011

    Precisely. The consequences of catastrophic dam failures are essentially limited to devastating flood events. Similarly catastrophic nuclear power plant failures can produce very long term consequences.

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  9. 9. Anne Jefferson 3:12 pm 06/21/2011

    I agree that dam safety is an important issue, but I think this article is overly sensationalistic and lacking in context.

    Most of the 80,000 dams are far, far smaller than the mega-dams like Grand Coulee that you mention. The dams at risk of failure in the US are mostly small (and privately owned), failure could cause flooding and deaths but almost certainly not on the scale your readers would envision after reading this article. Big dams are mostly hydropower producing, and these are relicensed every 30 years by the federal government (FERC). Part of that extensive relicensing process includes safety checks and management plans.

    As for dams and earthquakes in China, while there has been speculation of a linkage between the Sichuan earthquake and reservoir construction, it is far from proven (and an earthquake would have occurred there at some point soon, even without any reservoir. Drawing the connection between Sichuan and the Three Gorges dam is irresponsible; the tectonic settings are very different (e.g.,"the risk of an earthquake powerful enough to bring down Three Gorges Dam is remote", Landslides into the reservoir are the main earthquake-related hazard for Three Gorges.

    A better article might have talked about small dam safety issues and the dam safety and dam removal programs designed to address them. That’s a real issue. It could have talked about the history of dam failures in the US (which would have shown that the problems come from private, not federal) dams. It could have addressed levee failure, which probably puts more people at risk of flooding each year than dam failure.

    I’m far from a fan of big dams; they have undeniably devastating environmental consequences and they frequently displace already disadvantaged human populations. Portraying big dams as big killers is sensational, but unrealistic.

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  10. 10. Dr. Strangelove 12:59 am 06/22/2011

    "On a per kilowatt-hour basis, dams are the most dangerous source of electricity generation… A series of dam failures in China in the 1970s killed more than 200,000 people."

    I thought pollution from coal power plants cause 400,000 premature deaths every year in China. I believe that figure came from another article in SciAm.

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  11. 11. Grumpyoleman 8:01 am 06/22/2011

    I trust the author is not suggesting that the Teton Dam failure in 1976 was that of an aging dam. The Teton Dam had only been completed for 7 months when water leaking through the highly porous soil on which the dam was built caused a breach.

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  12. 12. Dr. Strangelove 10:29 pm 06/22/2011

    The author is exaggerating the danger of dams. Dam failures are often caused by engineering design or construction flaws. And why would dam failure kill 200,000 people if they weren’t living in danger zones downstream of a dam? There was safety lapse there.

    Anyway, car accidents worldwide kill about a million every yr. So if dams are dangerous, cars are more dangerous and we shouldn’t be making cars.

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  13. 13. ennui 5:43 pm 06/23/2011

    A Power Station, using Gravity Control does not need dams, wind, solar or nuclear and can generate power @ 1 cent per Kilowatt. Show me any other system that can do that.

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  14. 14. electric38 1:33 am 06/24/2011

    One of the more interesting ideas that could be implemented along with the rebuilding of these dams is to allow a solar farm to be built along side the dam. This would allow the power of the sun to energize pumps to force water uphill (back to the feed side of the dam). This could be used for the turbines during peak periods. Not quite perpetual energy but a very close relative. A lot of unused sunshine could be put to work on at least some of these 80,000 dams.

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  15. 15. ennui 3:21 pm 06/24/2011

    A Power Station, built on the Gravity Control Principle can generate power @ 1 cent per Kilowatt.
    Gravity Control is used by the Flying Saucer, the technology was discovered and patented. These spheres underneath are the Propulsion Units. They can lift a 10 or 1200 ton vehicle off the ground and beyond with a small amount of energy with the technology used.
    A PU can also lift a weight of that size in an elevator to maximum height. When released, the weight can activate a generator. A Power Station would have two silos, working alternately and can even be buried up to ground level.
    Not any other system can do that.

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  16. 16. SkyKing169 5:00 pm 06/24/2011

    Typican Scientific community.
    The narration in the video is uninspired, uninspiring, and completely lacking in passion and conviction, and the article had some factual errors that weren’t reviewed and repaired before publication.
    Readers, instead of building on the work of the author, no matter how flawed, instead somehow thought it was their job to critizice and find flaws in the work.
    Those commenters will never succeed at accomplishing anything worthwhile, despite a desperate need for us as a society for them to do so. Until and unless they learn to build on the work of others, to help instead of hinder, they will never be more than the losers characaturized by the quip that an ‘outgoing’ scientist is one who looks at the other person’s shoes instead of his own.

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  17. 17. MikeO 10:49 am 06/26/2011

    Yankee, In MA is, I am told the same (but less upgraded design) and they have already asked for extension .

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  18. 18. Dr. Strangelove 10:15 pm 06/27/2011

    Why not just use the electricity produced by the solar farm? If you pump water up to a dam reservoir to produce hydroelectricity, there will be energy loses in the water pump and the water turbine. You already have electricity from solar, just use it directly.

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