OT: River ecosystems, well enough understood? maybe not

This, what looks to be a throwaway comment, caught my attention.

What could that “or something” include that people place value on?

Maybe we should try to understand what other forms of life, beyond the human-centric ones, thrive in and near river ecosystems?
And then understand, when a naturally flowing river is impounded into a reservoir, the biodiversity lost.
A reservoir is a very different physical environment relative to a river, having deeper, slower-flowing water, and of course a dam as a major obstruction to natural flow and animal migration.

Below are some links with cool photos that are a tiny sample of the biodiversity in U.S. rivers - in our own backyards (the Tennessee River and all of its tributaries is one good example, but there are many others).

I look at these amazing creatures and can’t help but believe this “is something” we should value and protect.

Fishes (scroll through for photos)

Freshwater Mussels (mussel larvae hitch a ride on fish)

Caddisflies (scroll down for photos)

New Species (we have plenty still to learn)


There are always tradeoffs. There is no perfect form of electricity generation. Suppose they tear down the hydroelectric dams in the name of biodiversity. What are they going to replace that dispatchable electric power with?

Should the dams be replaced with wind farms? First of all, wind farms are not dispatchable, but lets pretend for a moment that they are. What about the large raptors that will be killed by the blades of those rotating wind turbines? Are people willing to live with that loss of wildlife, on a big scale?

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Or maybe we should install solar farms instead? There is a cost to the environment there, as well.

A few snippets from the link above…
Over the last few years, this swathe of desert has been steadily carpeted with one of the world’s largest concentrations of solar power plants, forming a sprawling photovoltaic sea. On the ground, the scale is almost incomprehensible. The Riverside East Solar Energy Zone – the ground zero of California’s solar energy boom – stretches for 150,000 acres, making it 10 times the size of Manhattan.

“When people look across the desert, they just see scrubby little plants that look dead half the time,” says Robin Kobaly, a botanist who worked at the BLM for over 20 years as a wildlife biologist before founding the Summertree Institute, an environmental education non-profit. “But they are missing 90% of the story – which is underground.”

Her book, The Desert Underground, features illustrated cross-sections that reveal the hidden universe of roots extended up to 150ft below the surface, supported by branching networks of fungal mycelium. “This is how we need to look at the desert,” she says, turning a diagram from her book upside-down. “It’s an underground forest – just as majestic and important as a giant redwood forest, but we can’t see it.”

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The people who want to protect the eagles and hawks from wind turbine blades probably think those raptors are Something worth keeping. The people concerned about the delicate ecosystem of the desert probably think that is Something worth protecting, as well. To repeat, there are always tradeoffs.

Just something else to consider…

From the link below…

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The changing climate due to the rising atmospheric CO2 concentration is often described as an existential crisis. Whether or not it actually rises to that level of concern, the accumulating greenhouse gases are probably something that needs to be addressed. So, what tradeoffs are people willing to live with, in order to even slow down the rate of increase in the CO2 concentration?

  • Pete

In order to assess and act on the tradeoffs, one must understand all sides and understand that the “or something” portion, to use your phrasing, can have a lot to unpack. You provided more examples of unpacking the details of the “or something,” which is good.

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Agreed that there are tradeoffs. Just as there are in trade policy (lower costs for all vs loss of jobs for few) and virtually any other matter of importance. When it comes to dams, there’s a misunderstanding that most are federal and provide hydroelectricity. Neither assumption is true. The vast majority are private and poorly regulated. But even if we narrow the discussion to large dams, you’d be surprised how many produce no or very little power. After the first major phase of U.S. Govt dam-building in the 1930s, the U.S. went on a spree of building in the 1950s, 1960s and 1970s, and the quality of the projects declined as the best sites were built out and the responsible agencies just found more questionable sites with fewer solid benefits. A lot of the later projects should have never been built; now that we have them, it’s up to us to evaluate their value and decide their future.

It’s also worth noting that several of the dams in the news that are coming down are doing so because their private owners don’t see the business case anymore. These people aren’t environmentalists; they compare the costs of necessary investments and upgrades for structures that are decades old versus the likely profits and agree to their removal.


True, but perhaps misleading. Some are used to store water for agriculture. Some turn rivers into lakes for recreational boating and fishing. Some are used to mitigate seasonal flooding (many, perhaps even most of the TVA system of 50 dams are for flood control).

Yes, there are second level effects, and rivers are unquestionably impacted. It took a while to realize that fish ladders were needed to allow certain species to travel back upstream to spawn, for example, and the lesson was likely not learned until a die-off was noticed.

That said, dams do a lot of good, although some of them do not and should be removed. It’s too facile just to say “we need to get rid of them if they don’t produce power” - or even if they do.


Agreed on the fact that dams are often multi-purpose, though I’m a bit confused about the “misleading” comment. We were talking about hydroelectricity, rather than the entire suite of purposes. If you wish to go down that road, the economic value gets very murky on a lot of projects. Recreational purposes in particular are often overstated in cost-benefit analysis.

I agree that some dams do a lot of good. Others do not. In the U.S., the dam building era is over. The issue now is what we do with the aging structures we have.


What do the beavers say about it? They are the #1 dam builders…

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… and culvert cloggers …

One has to wonder which engineering schools they attended.

The Captain

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The very best, but the course of study is, uhm, eons long.

david fb


And many dams are being removed to restore natural flow to rivers.

@jerryab2 @flyerboys
As for the beavers, they are an important component of the river landscape, adding habitat diversity and likely contributing to increased aquatic diversity in river ecosystems - in the same vein as beavers have had eons to develop their engineering behavior, river life has had many, many generations to evolve in response to beaver activity.

“Obsolete and dilapidated dams abound across the nation. We believe at least 30,000 dams (out of more than 400,000) can be removed to revitalize streams and bring rivers back to life. After all, life depends on rivers. My life, your life, your children’s lives, even your dog’s. We are counting on our community of dam removal enthusiasts, supporters, and even those who did not realize dams could impair streams to join with us.”