Dam Trouble

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nita

Social climber
chica de chico, I don't claim to be a daisy.
Feb 13, 2017 - 10:20am PT
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Just remember this situation the next time the water guys start talking about building yet more dams, like at Sites and Temperance Flat.

That quote is exactly my thoughts on building more nuclear power plants..
Reilly

Mountain climber
The Other Monrovia- CA
Feb 13, 2017 - 10:34am PT
you don't have any role in this, of course, except to be a public scold...

If he was scolding Trump you'd be saying he's being a concerned citizen.
Dave

Mountain climber
the ANTI-fresno
Feb 13, 2017 - 10:37am PT
There are known, written standards on how to operate and manage dams.

Oroville has, apparently, had listed deficiencies that went unaddressed for up to 12 years. Unacceptable for a severe-consequence dam (have you seen the inundation maps?)

The main spillway had holes that should have been addressed long before it had to be used. There was no reason that the main spillway should have failed initially. Without that failure, the emergency spillway would not have had to been utilized.

The root cause is poor management decisions in the past when they had the opportunity to address them. perhaps along with that is lack of budget attention from above - up to possibly the CA legislature.

Ksolem

Trad climber
Monrovia, California
Feb 13, 2017 - 10:39am PT
There's only so much money for everything to go around and politics play a huge part of it especially when;

$68B train to nowhere.

Back to the dam, any experts here want to chime in on the subject as to why the emergency spillway has nothing but dirt underneath it...

Also, if a big sinkhole collapsed under the main spillway does that mean water has been leaking under there for a while?

Just curious.

nita

Social climber
chica de chico, I don't claim to be a daisy.
Feb 13, 2017 - 10:46am PT
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*
Oroville has, apparently, had listed deficiencies that went unaddressed for up to 12 years.
Exactly.....i posted this up yesterday and Hooblie reposted the text.

Edit: The environmental Liberals called the alarm..... Three environmental groups ó the Friends of the River, the Sierra Club and the South Yuba Citizens League ó filed a motion with the federal government on Oct. 17, 2005, as part of Oroville Damís relicensing process, urging federal officials to require that the damís emergency spillway be armored with concrete, rather than remain as an earthen hillside.

http://www.mercurynews.com/2017/02/12/oroville-dam-feds-and-state-officials-ignored-warnings-12-years-ago/

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tuolumne_tradster

Trad climber
Leading Edge of North American Plate
Feb 13, 2017 - 10:51am PT
I posted this article on the California thread back on Jan 13, 2017 but might be worth reposting here...

NYT article on the great flood of 1862 which resulted in tragic loss of life and an estimated $10M in damage...that was a lot of $$ back then...
http://www.nytimes.com/1862/01/21/news/the-great-flood-in-california-great-destruction-of-property-damage-10000000.html

The rainy season commenced on the 8th of November, and for four weeks, with scarcely any intermission, the rain continued to fall very gently in San Francisco, but in heavy showers in the interior. According to the statement of a Grass Valley paper, nine inches of rain fell there in thirty-six hours on the 7th and 8th inst. Whether, it is possible that so much rain could fall in thirty-six hours I will not decide; but it is certain that, the amount was great, for the next day the river-beds were full almost to the hilltops. The North Fork of the American River at Auburn rose thirty-five feet, and in many other mountain streams the rise was almost as great. On the 9th the flood reached the low land of the Sacramento Valley.

For more info on ARkStorms, see the USGS Open File Report 2010-1312. Note Appendix A of this report summarizes damages/loss of agricultural crop, livestock and field by county based on 2009 $$$ due to a major ARkStorm.

https://pubs.usgs.gov/of/2010/1312/
Dave

Mountain climber
the ANTI-fresno
Feb 13, 2017 - 10:51am PT
"[1]Back to the dam, any experts here want to chime in on the subject as to why the emergency spillway has nothing but dirt underneath it...

[2]Also, if a big sinkhole collapsed under the main spillway does that mean water has been leaking under there for a while?"

2- not necessarily. Could be they used precast concrete panels without sealing joints, or had cracking that got big enough to leak through. Any of a bunch of reasons that the failure could have occurred.

1- it looks to me like the issue is the pool at the end of the spillway - the turbulence eating out under the end of the spillway. I don't know what design standards were in the 1960's when this was built, but it is possible they don't have sufficient (size & amount) rock to break up the energy from the water at the end of the emergency spillway.
sempervirens

climber
Feb 13, 2017 - 11:02am PT
This was forwarded to me. It originates from Calfire.


CONTACT: 530-268-5869
RELEASE DATE: February 13, 2017


FOR IMMEDIATE RELEASE

Spillway Incident Press Conference

Oroville, Calif. Ė There will be a press conference at noon today, February 13, 2017. It will be held at the State Parks Headquarters, 400 Glen Drive Oroville, CA 95966.

Lake conditions, including lake levels, inflows, and outflows can be obtained via a recorded message at 530-534-2307. More information is available on the California Data Exchange Center.

neebee

Social climber
calif/texas
Feb 13, 2017 - 11:03am PT
hey there say, nita... yep, me too... trying to follow this for some time
now, too... floods and rain, etc...

i may not be in calif, anymore, but my love for it is still there...

say, i was SHOCKED when i learned that no one EVER
taught us, in school about the SACRAMENTO WEIR,
and what happened to the sacramento valley, way back when,
and WHY it was built...

man oh man... i sure learned a lot from just wondering about
how folks were going to be, from all this... :O


say, once again, thank you to all that are sharing here...
i keep jumping back here, in between my day...
so much to learn about all this,
though, sadly, that does not stop the trouble...

:(



thank you again all, for caring to share...
Gnome Ofthe Diabase

climber
Out Of Bed
Feb 13, 2017 - 02:03pm PT
I've got to start dinner right now but
Here is the link from the 'Sacto' Bee; about the Weir
(Ha! not, Bobby? Once The only well known Californian Weir)

http://www.sacbee.com/news/weather/article126253529.html

mike m

Trad climber
black hills
Feb 13, 2017 - 02:30pm PT
When the water does go down I bet there aint much of that spillway left. Hopefully it is still there.
couchmaster

climber
Feb 13, 2017 - 03:47pm PT


Sorry, did I say Trump? I meant it was Bush's fault Jody.

Bush's fault.

August West

Trad climber
Where the wind blows strange
Feb 13, 2017 - 03:52pm PT
[posted on another thread before I saw this one]

The erosion on the emergency spillway is a design issue, not a maintenance issue. That spillway is nominally designed for 350,000 cfs. But a flow of 6,000 to 12,000 cfs for a few hours caused enough damage to order an evacuation. A little bit of maintenance would not have fixed that. The Mercury News article on this was pretty good. The spillway should have been lined with large boulders to prevent the erosion that happened.

Since emergency spillways are rarely, if ever, used. Experiencing some damage during use (and then repairing as necessarily) can be cheaper than a more expensive design while still protecting the dam from failure. But if a flow that is only 5% or so of the design flow causes serious damage, then it wasn't designed/built correctly.

As far as large dams that would provide flood protection for the Sacramento and its tributaries, the good sites are pretty much all taken. The only remaining site that I'm aware of that has much potential is Auburn. Local politics, combined with the environmental loss, combined with the fact that congress would never allocate Federal money for it, probably ain't going to happen.

There has been too much development, too close to rivers. That makes it really expensive to provide flood protection. The lake level in reservoirs could be kept at lower levels which would provide additional flood protection. But then farmers would go ballistic if the state flipped back into a drought.

All of the current proposed dam projects that I'm aware of would only be for water supply during droughts. Having an off-river site that requires the water to be pumped into it does not provide flood protection. I'm not ideologically opposed to this on principal. However, I am opposed to spending tax payer money to provide subsidized water to farmers.

For where northern CA is at, for flood protection, it really comes down to building and maintaining levees.
August West

Trad climber
Where the wind blows strange
Feb 13, 2017 - 03:59pm PT
"[1]Back to the dam, any experts here want to chime in on the subject as to why the emergency spillway has nothing but dirt underneath it...

As I just posted, if you only use an emergency spillway once every 50 years or so, having some damage and repairs can be a reasonable strategy. But clearly not in this case.

[2]Also, if a big sinkhole collapsed under the main spillway does that mean water has been leaking under there for a while?"

You mean the gated spillway not the emergency spillway? That could be, I know less about that. I did see a press conference where this was a known/expected issue and that the spillway is inspected every summer and occasionally repaired in order to prevent just this problem.

2- not necessarily. Could be they used precast concrete panels without sealing joints, or had cracking that got big enough to leak through. Any of a bunch of reasons that the failure could have occurred.

Is this still for the gate spillway or the emergency spillway?

If it is the emergency spillway:

The concrete that is part of the spillway where the flow leaves the lake, isn't the issue. It is erosion downstream of that. The downstream area should have been lined with boulders. If it erodes back up to the concrete spillway, the concrete will fail. But if the foundation is eroded, it won't have mattered what type of concrete was used.

If it is the gated spillway, I'm less sure. I don't think you can prevent a little bit of water from flowing underneath the concrete and causing erosion. The more important strategy is to inspect for this and repair as necessary. But maybe there was some issue with the concrete joints.

1- it looks to me like the issue is the pool at the end of the spillway - the turbulence eating out under the end of the spillway. I don't know what design standards were in the 1960's when this was built, but it is possible they don't have sufficient (size & amount) rock to break up the energy from the water at the end of the emergency spillway.

They could have brought in big enough rocks, but it would have cost money. Even if the rocks didn't prevent all damage, it would have slowed the rate of damage. When the dam went through the 50 year re-licensing process, it should have been required at that point (if not before).
rick sumner

Trad climber
reno, nevada/ wasilla alaska
Feb 13, 2017 - 04:23pm PT
By Thursday of next week, if the weather forecast can be trusted, California could be less it's largest dam.
John M

climber
Feb 13, 2017 - 04:24pm PT
Anyone know why they aren't letting people return home?
aspendougy

Trad climber
Los Angeles, CA
Feb 13, 2017 - 04:30pm PT
California is not unique in this regard, but is known for deferring hundreds of millions of dollars worth of infrastructure maintenance, until a real emergency occurs. Wait until someone's baby drowns, and there are big lawsuits, then it will get fixed. That's the way we usually do things here. Governor Brown would rather invest multi-billions in bullet train, rather than divert the money to fix roads and dams.
G_Gnome

Trad climber
Cali
Feb 13, 2017 - 04:33pm PT
So they are running less water down the main spillway not because it has a giant hole but because it threatens power lines?! Screw the power, let's flood 200,000 people instead. Sometimes you really have to wonder over the decisions made.
10b4me

Mountain climber
Retired
Feb 13, 2017 - 04:40pm PT
Hey, let's build more dams so that they can fail too.
SalNichols

Big Wall climber
Richmond, CA
Feb 13, 2017 - 04:40pm PT
DWR says that the main Feather River has a peak capacity of around 150k cfs. It gets sketchy beyond that as levees begin to fail. He said they could go to 130k cfs with the damaged spillway if they need to, but they were operating at 100k cfs, holding the 30k in reserve as a safety for downstream.
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