Why Europe is dismantling its dams

The Australian Greens (one of the earliest Green parties) were founded basically off the back of opposition to dams in Tasmania: https://en.wikipedia.org/wiki/Franklin_Dam_controversy

Why do you find this ironic? Doesn’t this follow logically: Greens don’t want new dams due to environmental impact and now dams are been dismantled due to the negative impact on the environment.

It's a give and take. Historically, the danger from flooding actually increased because the floodplains next to the riverside were mostly eliminated. They would provide flexibility for the river to meander and to expand in times of heavy rain and would have to be restored as part of a dam removal. They also provide biodiversity and help keep the river water clean.

Dams are also a hazard when there is a lot of rain because you eventually have to open it or risk failure. As the dam gets older it tends to silt up and its integrity becomes less trustworthy, even less water fits in. This requires necessitating expensive maintenance to remedy. Getting rid of it might be cheaper in the long run.

Can't speak for the ones in this article but they're doing similar in the pacific northwest and many of the dams where built to locally control flooding, but other newer dams further upstream ended up handling the flood prevention better over what were previously multiple dams so there's lots of old dams that have effectively sat unused & blocking fish & wildlife on the river while also providing no benefit.

Every dam is different...but if a dam has a small reservoir capacity (perhaps partly due to lack of maintenance - so what looks like water behind the dam is mostly accumulated silt), a narrow range of control (the water level is not much different between "flood gates fully closed" and "flood gates fully open", local-only manual controls (vs. pushing a button at National Flood Control HQ), and other issues - then it's actually of little use for those.

No meaningful height differential. Which is one component increasing energy storage capacity linearly.

If wildlife is involved these are almost certainly small run-of-the-river dams.

For pumped hydro you need significant elevation differentials, a pretty good vertical, and lakes at both the top and bottom.

Sites suitable for pumped hydro are really not common, and the financial investment and utility means they wouldn't be getting dismantled.

I don't think any dams that produce meaningful amount of energy are going to be removed any time soon. These are the ones that used to power mills and like. So we are talking about way under 1MW in power each.

According to the article, not that effective:

> Evaluations concluded that their electricity production had become unprofitable for the power plant owners – especially when the costs of maintenance and mandatory environmental protections, such as fish-ladder introductions, were taken into account, Ollikainen says. So the dams were sold and dismantled. [..] Across Europe, many dams are either approaching the end of their operational life, or the costs of their maintenance are outweighing the benefits they provide.

Aside from various other problems mentioned in the article, which really don't seem that easy to work around, and doing so would make them even less cost-efficient. Never mind all of this takes energy so would reduce the efficiency (although I don't know by what amount, but it does need to be factored in).

> Research now shows that at least 1.2 million instream obstacles block river flows in 36 European countries, with about 68% less than 2m (6.6ft) in height

I think we are talking about those dam, not the big ones.

> "Absolutely nobody is proposing to blow up or remove barriers which are in use," clarifies Garcia de Leaniz, "We are targeting barriers which are obsolete, which are no longer providing any services to society, that have silted up, and pose a flow hazard."

Dams are terrible for the environment(generally poison everything with methyl mercury), and in many cases aren't even that green, since they produce a lot of methane (dam water goes down in summer, that area growns plants, fills up in winter, plants then decompose in an anaerobic environment, producing methane). Depending on the size of the lakes this can be a very large area, ie: big hydro dams in Quebec/BC. There's been research to show one hydro dam produces more greenhouse gases than an equivalently sized coal plant in Brazil.

It sounds like you're trying to speak for everyone. Clearly there is a balance (money needs to be spent building new generation of some type). But we can work on climate -and- avoiding the extinction of vital fish species by restoring the flows of rivers. I don't think the systems at large will afford humanity a second chance or "over time" if we fail to act.

Most of these dams are explicitly uneconomical to run with modern safety standards and 50 years of being under-maintained. There's a lot of dams that were built, the original owners eventually figured out they weren't as profitable as planned, and just wanted to abandon it. An abandoned dam is a future "natural" disaster waiting to happen. And most of these dams were built with pretty mediocre standards, and we don't even build these kinds of dams anymore because they have all sorts of ways of failing unexpectedly.

They have to come down because they were privatized gains, socialized losses as usual. Private companies built them, decided they didn't want them anymore, and basically handed communities unmaintained dams and said "deal with this or drown when it fails". Communities generally don't like being saddled with the waste and consequences of a failed or finished private venture.

We in the US had a huge dam boom at one point, turns out most of them were over-optimistic.

While I broadly agree with you, most of the dam removal projects I see in the US are tiny dams which have little to no potential for use as fresh water sources and generate tiny amounts of electricity.

I'm strongly in favor of replacing the lost capacity with much larger dams though which have the ability to hold non-trivial amounts of water and have the ability to generate significant amounts of power.

Relatively speaking, the ecological impacts are disproportionately large for what we gain with smaller dams.