[HN Gopher] The largest dam removal in US history is complete
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The largest dam removal in US history is complete
Author : pseudolus
Score : 39 points
Date : 2024-09-04 00:56 UTC (22 hours ago)
(HTM) web link (www.bbc.com)
(TXT) w3m dump (www.bbc.com)
| blackeyeblitzar wrote:
| I am not sure that dam removal is the right decision for every
| dam, but it seems like there is a movement in that direction. A
| lot of what I hear locally when people push for dam removals
| seems like emotional activism rather than rational thinking.
| Losing hydroelectric power, facing renewed flooding seasons,
| losing easy navigation, etc. may not actually be an overall
| positive change.
|
| And the goals feel arbitrary - like when people say they want to
| "restore the environment", I wonder why it makes sense to restore
| it to any particular particular point in time when all these
| rivers have changed over time. In other cases, where the goal is
| restoring fish populations, there are alternative methods of
| helping the fish population and a dam removal seems like a very
| expensive method with other risks.
| pengaru wrote:
| AIUI these dams have a limited lifetime either way. Giving the
| natives and activists what they've been fighting for is a sort
| of consolation prize for something that was a cheaper option
| than proper repairs/maintenance.
|
| What I wonder is how long before new dams are being built in
| their place. Maybe after all the ailing bridges have been
| fixed, and there's another pile of federal money desperate for
| "green infrastructure" projects to be spent on...
| WorldMaker wrote:
| Since the time that many of those dams that are worth
| demolishing for poor repairs/maintenance the federal
| government has also made it harder to get permits to build
| new dams. They require more environmental studies up front.
| They require more study of downstream effects. Things like
| salmon, which are very sensitive to changes in river
| conditions, now have to be taken into effect earlier in
| planning stages and it is a growing requirement that any
| river to be dammed that include salmon hatcheries now has to
| plan for sub-projects like salmon runs (or with certain
| exceptions salmon cannons).
| hooverd wrote:
| I'd say the stated goal of improving the river ecosystem was a
| success.
| Gormo wrote:
| What does "improving the river ecosystem" mean?
| 83 wrote:
| This is largely addressed by the article. Improved
| biodiversity (more fish, more native vegetation and the
| bugs/wildlife that go with it) as well as improvement of
| the water itself like the elimination of dangerous algae
| blooms.
|
| From the article: The dams also had a severe impact on
| water temperature and quality - growth of toxic algae
| behind two of the dams resulted in health warnings against
| water contact.
|
| Also from the article: "where we've seeded is green, we're
| seeing flowering plants teeming with life. I counted eight
| different butterflies in the areas we hand-seeded. There's
| moths, hoverflies, bees, birds. It's been a really exciting
| first year."
| pkaye wrote:
| There are many small dams that are at end of life and no longer
| worth replacing. The company that owned this dam was in favor
| of removing it.
| marssaxman wrote:
| Many of the primitive hydropower dams built a century or more
| ago have a production capacity which is negligible by modern
| standards. The two dams removed from the Elwha river here in
| Washington were the lowest and third-lowest producers in the
| state; the capacity lost by decommissioning them was utterly
| overwhelmed by the new wind and solar capacity added in a
| single year.
|
| I don't recall precisely how much power the Klamath dams
| generated, but when I looked it up, though the numbers were
| larger, the overall situation was similar: the hydro capacity
| California lost was inconsequential given the growth in other
| renewable sources.
|
| It's not so much that the river needs to be restored to a
| particular point in time as that the river needs to actually
| _be_ a river and not a lake, if it is to support a river-
| dependent ecosystem. Water temperature, flow rate, presence of
| shallows, shade, woody debris, and so forth are all
| environmental elements which have a large effect on the
| viability of a habitat for keystone species like salmon. You
| can 't just fake it with fish ladders.
| briankelly wrote:
| You should check out Cadillac Desert. Many dams in the US were
| built with no rationale beyond capturing federal infrastructure
| funds by local politicians and resume driven development on the
| part of the US Army Corps of Engineers and the Bureau of Land
| Reclamation.
| mechagodzilla wrote:
| It was a pretty eye-opening book. I think most people assume
| individual dams provide far more value than they often do in
| practice.
| UniverseHacker wrote:
| I agree- but I don't think anyone is saying it is right for
| every dam. However, a lot of dams probably just aren't worth it
| on net when you do consider all of the factors, and massively
| decreasing prices of alternatives.
|
| There aren't really solutions for migratory fish that support
| the kind of populations the rivers supported without dams...
| especially the ancient and poorly designed dams already in
| place. For example historical estimates are that ~16 million
| salmon migrated in the Columbia river despite being a major
| food source for a large number of Native Americans over a
| massive area. Nowadays, with every practical measure in place,
| lot of hatcheries, and almost no fishing those numbers are only
| up to ~1 million.
|
| Obviously we're probably not going to return to ~16 million,
| but the impacts of not doing so are widespread and far lasting-
| for example salmon coming upstream are historically a major
| source of nitrogen for the forests in the northwest, and
| without them long term, the forests will be something
| substantially different and diminished - with far reaching
| impacts on the entire ecosystem and many other resources of
| value to humans[1].
|
| Gradual loss of the deep soil and peat from those forests also
| causes flooding and drought as the soil no longer stores large
| amounts of moisture that is slowly released over the dry
| season- e.g. ecological changes from dams may in the long term
| actually make flooding and drought more severe rather than
| less.
|
| [1] "total annual growth per unit forest area (m2*ha-1*yr-1)
| was more than three times higher at spawning sites relative to
| reference sites"
|
| https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890...
| bsder wrote:
| > A lot of what I hear locally when people push for dam
| removals seems like emotional activism rather than rational
| thinking.
|
| It's more maintenance and liability transfer, but
| environmentalism gets more clicks. A lot of these dams are
| small, old, and poorly designed even by the standards of the
| day. They provide a negligible amount of electricity by today's
| standards. And, if they fail, they'll do a lot of damage.
|
| Removing them isn't really up for much debate. The question is
| always "Who pays for the removal?"
| reader_x wrote:
| I lived and worked in Oregon in the early 90s, and this is huge
| news. I'll admit I'd gradually let cynicism overtake hope this
| outcome was possible. Now on East Coast, interesting to me that
| I'm first reading about this from BBC News and not US east coast
| media, which I believe has never appreciated the scale or
| importance of these land use decisions.
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