Unfortunately, the U.S. has been a dam-building nation since the beginning. Perhaps a thousand have been removed. That may seem like a healthy number, but:
As dams age and downstream development increases, the number of deficient dams has risen to more than 4,000, including 1,819 high hazard potential dams. Over the past six years, for every deficient, high hazard potential dam repaired, nearly two more were declared deficient. There are more than 85,000 dams in the U.S., and the average age is just over 51 years old.
More than a third of those dams were built during a twenty-year bender spanning 1950-70. The projected useful life of most of them was 25-50 years. The linked page includes data on maintenance costs, and the projected shortfall thereof.
The advocacy organization American Rivers has an interactive map that is a good starting point for this issue. One might think that 85,000 dams would be regarded as plenty, but apparently there are those that beg to differ. There’s money to be made, after all.
The value of many dams for flood control is mitigated, to say the least, by the fact that their reservoirs have almost filled with sediment. And it’s not like dams are the alpha and the omega, anyway.
CoreLogic “estimates flood losses in the U.S. this year at approximately $10.67 billion, based on various flooding and storm events recorded in the National Climate Data Center.” The extreme flooding was caused by the most extreme hydrologic conditions in the United States in history – most of the nation was in either extreme deluge or extreme drought.
In other words, when it comes to “flood control,” having a landscape dotted with dams, isn’t cutting it. Yes, matters would be worse without some of them, but they’re no cure-all. An approach that de-emphasizes the “man can tame nature” arrogance represented by dams, needs to be accelerated.
The American Rivers website that I linked previously is packed with good stuff, but perhaps the best is this page, about hydroelectric power.
The focus on hydropower in the coming years must not be on building new dams, but instead on maximizing efficiency, responsible operation, and environmental performance.
The extent to which hydropower needs to be a dominant part of conversion to a green electricity grid isn’t nearly as much of a given as its proponents would have us believe, as the efficiency of solar generation, both micro and macro, continues to improve. (I will note that “micro-hydro”is an intriguing concept that would seem to have a lot of potential.)
The need for dams to continue to divert massive quantities of water for agricultural use would certainly seem to be obviated by the facts regarding the amount of agricultural production in the U.S. that is wasted, pure and simple. Estimates of that, that I’ve seen, range from 25 to 50 percent. I chose the linked article, which suggests that the high end of that range is correct, because it’s full of good links. Note that wasted food also entails the waste of all of the inputs that went into producing it.
A number of issues render dam removal more complex than just ripping the things down or blowing them up. One of the most challenging, is that the sediment that has built up behind the dams, is also rife with all of the toxins that have washed down from upstream, over the decades. In many cases, the enormous quantities of sediments make dredging impractical, and you’d still have all of that sloppy, contaminated soil to deal with, anyway. That’s a tough one.
Even among environmentalists, there is a lot of controversy regarding the ecosystems surrounding dams. Over time, they’ve tended to adapt themselves to effects of the structures’ presence. It’s very unclear, whether any deliberate effort should be taken to try to restore them to something approximating “pristine” condition. If you’re getting into this issue, this report is a solid place to start.
With so much else that needs to be done, for both our infrastructure and our environment, this would certainly seem a good time to really hit the gas, when it comes to ridding the earth of useless, antiquated structures that are doing us all more harm then good – including, in many cases, dams. It’s a big challenge, but challenges are what make life interesting.
I admit to a degree of emotional involvement, in all of this. Dams, to my mind, often represent raw hubris, the belief that we can subjugate the forces of nature to our convenience and pleasure, without consequence. Any blow to that mindset – for example, seeing a big dam, that was pimped during its construction as a “lasting monument to human ingenuity,” and so forth, come down – almost makes the process well worth it, just on its own.