
Removing old, obsolete dams restores life to creeks and streams - fludlight
https://www.riverkeeper.org/campaigns/river-ecology/saving-hudson-river-fish/dam-removal/
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qchris
If anyone's interested in rivers and dams, and some of history and influence
they've had on the formation of the US (and vice versa), there's a great book
called _The Source: How Rivers Made America and America Remade Its Rivers_.
Not affiliated with the author in any way, but I picked it off a shelf last
year and found it a really good read.

This kind of thing brings up a bit of mixed feelings for me. On one hand, it's
indisputable that damming rivers has a negative impact on the ecology of those
watersheds. On the other hand, in an era of climate change, it seems like
trying to hold on to as much freshwater capacity as possible also seems like a
prudent idea, and I'm not sure what the best way to reconcile the two would
be.

~~~
StanislavPetrov
>On the other hand, in an era of climate change, it seems like trying to hold
on to as much freshwater capacity as possible also seems like a prudent idea,
and I'm not sure what the best way to reconcile the two would be.

Climate change doesn't mean warmer temperatures everywhere or a dearth of
freshwater. The Hudson Valley area referred to here has plenty of fresh water,
is projected to become wetter according to most climate change models, and has
become wetter recently (significantly so the last few years).

[http://www.cnyweather.com/wxrainsummary.php](http://www.cnyweather.com/wxrainsummary.php)

~~~
thaumaturgy
I forget the exact numbers, but something like 60% of California's freshwater
supply is stored in the Sierra snowpack, and the current models are projecting
that California will get more rain overall but vanishingly little snow.

California politically tends to be completely opposed to building new
reservoirs, and a large amount of seasonal northern California rainfall
ultimately gets routed out to the San Francisco Bay through storm drainage.

The other barrel of this particular footgun is that agriculture is still
California's biggest industry and they require an absolutely enormous amount
of water. This is already causing strain on state politics, because the
central valley keeps demanding more water from northern California, which
doesn't want to give up more of it, and southern California has just about
drained the Colorado river, and restrictions on water rights are the single
biggest driving force behind all the "State of Jefferson" signs you see in the
rural northern counties.

I love California but the water situation is about to bite them really hard.
"About to", of course, still being a decade or two out, but there don't seem
to be any reasonable solutions to this intractable situation on the horizon.

~~~
namibj
California could trivially afford to just buy out the alfalfa farmers, paying
them actually a slight premium compared to the revenue from their alfalfa
farming.

That alone would fix most of California's water problem.

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acd
A friends works as an ecologist and are a scientist at a university. Water
Dams disrupt/destroy eco systems downstream. Hydro power is thus not fully
green due to that. Water power has to be compared to The alternatives such as
oil/coal. One should not view water power as fully “green” energy.

Fish species are for example disrupted by water dams.

~~~
generatorguy
I’ve worked on about 30 different run of river hydro electric projects over
the last 15 years. Yes there is some environmental impact but the ones I have
worked on have had a team of biologists and years of environmental studies and
they would never result in a dead fish any more often that the river would
have naturally by itself. If any habitat is destroyed they have to create new
habitat such as spawning channels. They probably spend 10%-20% of the entire
budget on environmental. These run of river plants don’t flood more than
1000m^2 area, use a weir instead of a dam, leave water in all sections of the
river channel, and don’t cause unnatural changes in the river level at a rate
greater than 1” per hour which is a very conservative rate compared to what
the rivers of this size and nature naturally do by themselves when it rains or
melts.

I know you said Dams and not weirs and not run of river plants, and big dams
have their issues, but not on the same scale as the oil industry.

~~~
helldritch
I'm curious how well this applies to the short-term effects of filling the
Grand Ethiopian Renaissance Dam? [1]

As I understand it a lot of the downstream ecological effects rely entirely on
the fill rate the Ethiopians choose (3 years, 5 years, 10 years, 15 years,
etc). A fast fill rate (5 years or less) could have significant short to
medium term effects on the arable land downstream in Sudan and especially
Egypt.

The dam is oversized for its power output (to ensure it can meet peak output
demands during the wet seasons) and will operate as a fish trap, cutting the
number of fish able to head downstream (and ultimately to the sea / mouth of
the Nile) by a significant amount.

[1]
[https://en.wikipedia.org/wiki/Grand_Ethiopian_Renaissance_Da...](https://en.wikipedia.org/wiki/Grand_Ethiopian_Renaissance_Dam)

~~~
generatorguy
Large dams are a different ball game than the small run of river plants I have
worked on and the ones discussed in the article.

Even at large dams it is possible to build fish ladders to allow migration.

When we were filling our head ponds (reservoir) we weren’t allowed to impound
more than 10% of the total flow in the river.

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markvdb
See als
[https://en.wikipedia.org/wiki/Fish_ladder](https://en.wikipedia.org/wiki/Fish_ladder)
and similar initiatives to allow migratory species to pass dams.

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aaron695
Humans are putting ongoing pressure to all environments.

We need to stop with the bringing it back to how they were BS. It can't
happen.

Environments need energy and water to thrive amoungst other things.

It's hard to see dams being bad overall. Yes it might harm certain things. But
we need to start looking the bigger picture. Not little factoids like bringing
back wolves.

I find India's push on johads perhaps a little off topic but perhaps not. Be
need to start keeping fresh water on or in the land.

[http://www.ecotippingpoints.org/our-stories/indepth/india-
ra...](http://www.ecotippingpoints.org/our-stories/indepth/india-rajasthan-
rainwater-harvest-restoration-groundwater-johad.html)

~~~
pvaldes
I'm saying this in a polite tone.

But sorry. Anybody that equals key species with "little factoids" don't
understand a single thing about ecosystems. Would be like saying that the
motor of a car is an optional part of the car.

Wolves are boosters of biodiversity and change all around them.

