As XT pointed out earlier your statements don’t appear to match reality. If you’re only going to support them with the old “do your own research”-canard I’m just going to assume you don’t hold the site’s tag line in your hard.
The Greens and the Sierra club think that the only way is to cut back usage and reduce the populations. To them, there’s no such thing as green power, it’s all evil. The Sierra club just spend years and tens of thousands fighting a solar array, and want to dismantle all the dams, even the one we need for water. Their dream is to drain Hetch-hetchy.
Which is a good case for rebuilding it. Not tearing it down and not replacing it.
Why? Did you see all of the environmental impacts the dam was causing? And what the costs would have been to rebuild the thing? Seems to me that tearing it down will have a much more positive impact on both the locals and the environment. What makes you say they shouldn’t be tearing it down but instead rebuilding it? 
14.8 megawatts of electricity , green, and carbon-free. No pollution, no global warming.
and look at the huge costs involved in tearing it down.
But there would have been an equally high or even higher cost to rebuild the thing. Just the fish tubes they were talking about having to put in would have been very expensive. Turbines probably would have needed replacing and the concrete was failing. It would have been massive to fix.
It’s a cost to benefits sort of thing. I agree, 14.8 megawatts is nothing to sneeze at. But the cost to repair and replace coupled with the continued ecological damage…just doesn’t seem like the benefit was there verse all the costs.
So, where to get that 15MW from then? Coal?
Well, in the article they said the power was for a paper plant. No idea if that plant is even still working, or if they shunted that power to the local town. You are only talking about the power for less than 10k houses there. I suppose they could go with a wind farm or solar, or perhaps natural gas. I don’t know the details and you probably don’t either as to how easy or difficult it would be to replace that power in that area…or even if it actually needs replacing.
Yes, hydro dams have an environmental impact. Everything has an environmental impact. Compared to most other power plants, though, hydro’s impact is much smaller overall, and is only local. And it also has a number of other very nice properties, like being continuously reliable (unlike solar and wind) and the ability to turn it on and off very quickly to accommodate changes in demand or other supply (unlike coal and nuclear).
Of course, everyone else already realized how great hydro power is, so it’s already pretty well saturated.
You might want to rethink the bolded statement: it ain’t necessarily so. And while rainfall and snowpack depend to some extent on the El Niño / La Niña cycle, the likelihood of drought (at least by PNW standards) is projected to increase.
We’re thinking on different timescales. You might not know how much energy you’ll be able to extract ten years from now, but you certainly know how much you can extract over the next week, or hour, or minute.
That’s what impoundments are for … California emptied hers for irrigation, not power production.
Ignoring the very real impacts to the ecosystem hydro is not always “green” and in the case of the PNW is not “green”
Carbon dioxide and methane emissions from temperate regions like the United States can easily equal exceed the greenhouse effect of the carbon dioxide emissions from an equivalent amount of electricity generated with fossil fuels particularly with natural gas.
“Hydro” power may be good for cheap power but it is actually quite rare for it to be green.
Here is a cite to show that at least 20% of man-made methane comes from the surface of reservoirs and probably a much higher percentage does.
http://www.scientificamerican.com/article/methane-emissions-may-swell-from-behind-dams/
I notice that the OP has not returned to this thread for more comment. But I think I may have found what project set it off. More on that later.
A few months ago, I began researching dam removal. There’s quite a bit of such projects going on the the US, lesser amounts in Canada and Europe, and virtually none going on in the rest of the world. American Rivers website estimates there are about 85,000 dams in the US with around 1300 having been removed. From my other researches, most of these have been removed in the last 25 or 30 years. Before about 1970, almost all dams removed were because they were in the way of a larger project in the same river.
Anyway I tried researching dam removal. I found it rather hard to find out details about most of them. For some reason no one’s keeping track of them. But what I did find is that most of them are not hydroelectric or if they are, have fairly low capacity. For instance, in Maine, where the OP is, I found a handful of hydro dams removed, but the highest capacity was only 8 MW, and that was about 3 years ago. The largest capacity removal I could find was 22 MW, which was the Marmot Dam in Oregon.
However, there are some larger capacity dams proposed for removal. Most prominent are four dams on the Klamath River in California and Oregon. I see varying capacities cited for these, anywhere from 82 to 160 MW. However, those are a long way from Maine. I finally found a proposed removal in Maine: Kesslen, Twine Mill, and Dan Perkins Dams.
Yes, I was inspired by the Mousam River project.
Here in the PNW they are being removed for several reasons but it appears that the Mousam River project shares some similar reasons. It is not just access to spawning fish but the dams block sediment which causes the deltas to die. You don’t just lose your Salmon fisheries, you lose your shellfish too.
I am betting that lots of the smaller dams are either fully silted up and or pose a huge liability as the risk of breakage increases with age.
The point is that while there are probably dozens and dozens of arguments for keeping dams, hydroelectric power being more environmentally friendly than fossil fuels is not one that is backed by the data.
Two or three decades ago, there was an article in the New Yorker about a small dam in upstate NY that had once been used to generate a relatively small amount of power. The power company abandoned it, destroyed the feed pipe and sold it subject to a covenant that disallowed the generation of power. After the oil crisis in the mid 70s (recall the odd and even gasoline restrictions) the US passed a law outlawing such covenants. The owners of the dam then rebuilt the feed pipe and restarted the generator (which had not been removed) and started selling the power to the small town.
Hydro-Quebec has giant dams that they use to power the entire province and sell the excess to NY, especially during the summer for AC.
I don’t know why, all it does is just float there!
It never relies on Apple to ‘help’ it with spell checking, either. 