
Nearly 200K people told to flee crumbling California dam spillway - sndean
http://www.reuters.com/article/us-california-dam-idUSKBN15S04W
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maxerickson
Active overlapping discussion:

[https://news.ycombinator.com/item?id=13632708](https://news.ycombinator.com/item?id=13632708)

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65827
I remember reading about this when environmental groups were trying to raise
the alarm like 10 years ago. I recall quite clearly the attitude of
condescension and arrogance from the state and fed officials quoted, as if
anyone would dare question their unshakable engineering authority.

The sad part is no engineers were ever involved as far as I could tell, this
whole thing was just a kick the can budget gimmick. Gotta really start digging
into stories like this more instead of taking authorities at their word.

~~~
purple-again
Be careful with hindsight driven analysis. Show me a single large
infrastructure project in the United States with out environmental groups
protesting the potential impacts.

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BrailleHunting
I've family in Chico and we've toured the Oroville dam... it's massive,
tallest in the US, of the riskier earthen dam type and holds back a great deal
of water (3,537,577 acre feet (4.36e9 m^3), Shore length: 167 miles (269 km)
(WP)) which is sent through the California Aqueduct.

Also note there are internet hobgobblins spreading false rumors (over 400k
views on YT) about a risk of flooding Silicon Valley, which is over 150 miles
(210 km) away, well north of Sacramento. Primarily, the risks are to lowlying
areas like farmland and those immediately downstream of the dam in that area
around Oroville are at most potential risk. Furthermore, the evacuations were
mostly precautionary given the unstable/riskier nature of earthen auxiliary
spillways. Estimates of non-auxiliary spillway repairs are already in the
hundreds of megabucks. :(

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akhilcacharya
> Also note there are internet hobgobblins spreading false rumors about a risk
> of flooding Silicon Valley

Probably got the idea from the Bond movie

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thesehands
It's not clear if the damage was already there and accelerated by the influx
of water or if this was just freak damage caused by the influx. I seem to
remember John Oliver doing a piece on infrastructure and Dams were one of the
things he highlighted as being especially precarious through underfunding of
maintenance.

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manarth
The damage to the main spillway was "first reported" on 6 February [1]
(although it could have existed for longer and gone unnoticed). They had to
leave the spillway in use because of the amount of inflow, but on Friday they
reduced the spillway outflow to avoid damaging electric pylons [2].

They also had to halt outflow via the main hydroelectric discharge.

On Saturday, the emergency spillway started being used for the first time in
the dam's history. The operators thought this might happen, but didn't see it
as a risk.

The evacuation order was given when they saw the amount of erosion caused by
the outflow from the emergency spillway, fearing that if it carried on, the
emergency spillway could collapse. As a result, they've since fully-opened the
main spillway (100,000 cfs, rather than their previously reduced limit of
55,000 cfs), accelerating the damage to the main spillway.

So the damage to the main spillway existed at least a week ago. The emergency
spillway was seemingly undamaged, but once put it into use, caused damage
showing it wasn't really fit for purpose. And in trying to save the emergency
spillway, the main spillway is now sustaining further damage.

[1]
[https://twitter.com/CANGJ3OPS/status/829769462077284352](https://twitter.com/CANGJ3OPS/status/829769462077284352)

[2]
[http://www.water.ca.gov/news/newsreleases/2017/021017orovill...](http://www.water.ca.gov/news/newsreleases/2017/021017oroville.pdf)
(PDF)

