The Jury Talks Back

2/12/2017

California Spillway Failure Feared in Oroville, Could Cause Massive Flooding

Filed under: Uncategorized — Patterico @ 7:03 pm

The L.A. Times reports:

Residents of Oroville and nearby towns were ordered to immediately evacuate on Sunday afternoon after a hole was discovered at the emergency spillway for the Oroville Dam.

Officials said late Sunday they will attempt to plug the hole using sandbags and rocks but stressed the situation remains dangerous and urged thousands of residents downstream to evacuate to higher ground.

The National Weather Service said the auxiliary spillway at the Oroville Dam was expected to fail about 5:45 p.m., which could send an “uncontrolled release of flood waters from Lake Oroville.”

Just yesterday the public was told there was no danger. Now there are mandatory evacuations underway, traffic snarls, and a lot of confusion. Some reports state that the dam is danger of failing, while other reports (which appear to be more accurate) say that the emergency spillway is in danger, not the dam itself.

If the dam itself were to break, it would be catastrophic. The Sacramento Bee reports: Marysville, Yuba County evacuated as Oroville spillway collapse feared. Under a section titled Worst Case Scenario the paper says:

There is no map showing exactly what will happen if the emergency spillway collapses tonight. Officials only have a map showing a failure of the dam. That worst case scenario is useful in that it shows where water goes and how fast it gets there.

Water would get to the town of Oroville within an hour.

If Oroville Dam were to suffer a massive breach, water would get to the town of Oroville within an hour, according to GIS maps maintained by CalFire.

Within two hours, the small town of Briggs would be affected. In three hours, Gridley would be hit. Water would reach Live Oak in five hours..

It would take eight to 12 hours for the water to get to Marysville and Yuba City.

If the dam completely failed, flood depths could reach more than 100 feet in Oroville and up to 10 feet in Yuba City.

There’s some dramatic video here, but the statement in the tweet that the dam is expected to fail appears to be wrong:

[Cross-posted at RedState.]

8 Comments »

  1. Ding.

    Comment by Patterico — 2/12/2017 @ 7:04 pm

  2. I don’t know what sadder that according to the FB and twiiter comments that this is all the GOP and Trumps fault or the outright denials of pointing out which party has effectively run CA at the state level since the mid to late 70s. the blinders are big and the hypocrisy in many about tribal affiliation has caused a serious breakdown in proper government.

    I also wonder how many in Sacramento and Army Corps of Engineers, had warned of this as a possibility and constantly filed papers that went to the dead letter office of governmental archives.

    Comment by Charles — 2/12/2017 @ 9:19 pm

  3. There’s been a very great deal of confusion, largely because much of the press does not know what it’s talking about – but talks anyway. I’m disgusted by this when it’s media outlets that people at risk are turning to for news.

    There are three main things; the dam, the auxiliary spillway, and the emergency spillway. Many of the photos and reports have shown the concrete chute with a massive, growing hole in it, and called it the emergency spillway. It isn’t. It’s the auxiliary spillway.

    The emergency spillway is simply a concrete weir at the crest of the ridge that anchors the west end of the 770 ft. tall earth-core dam. Overflow from there goes down an unimproved mountainside to the feather river. It’s the concrete weir they were concerned would collapse, apparently due to erosion at its foot.

    There is no real danger to the dam itself; it’s thousands of feet from the emergency spillway. However, where danger *may* lie is if the emergency spillway collapses at the top as feared; that would create a 30ft or so deep gap, through which water will pour with massive force. The mountainside (the one that’s eroding and causing the issue) is supposed to be bedrock, and thus safe from eroding.

    These assurances are bought to us by the engineers who, a couple of days ago, said the emergency spillway was unlikely to see use. This was in spite of knowing the inflow and outflow rates – the same rates that allowed several people, including Roy Spencer
    http://www.drroyspencer.com/2017/02/is-failure-of-the-oroville-dam-possible/
    to predict not only that it would occur, but when.

    I have very little confidence in those engineers.
    If I was downstream of that, I would head for higher ground – including if I was in Sacramento.
    IMHO it’s unlikely that there will be a truly massive release – but it’s far from impossible.

    It’s also worth noting that the water levels are already quite high (due to all the rain) downstream, which would exacerbate the problem if there’s a significant failure release.

    Comment by Arizona CJ — 2/12/2017 @ 9:37 pm

  4. AZ CJ,

    First off with any media effort, they take worst case and make it doubly super, oh my god think of the children, worst case situations. So even if the media had a clue that the dangers are there, but more like “we are taking a jaded eye and observing” from officials. They still would act the way they do od being chicken little. Hence the increasing number of folks who ignore evac and storm warnings due to the excessive chicken little effects of the media.

    That said, after having friends experience a flood after flood in what was supposed to not be flood plain according to Engineers here in WA state and then the recent Oso tragedy which was from government not reading a danger report from some engineers. I am completely and totally jaded as to Government and its attitude of “i didn’t know!!!!!” there has been too many times reports, warnings, meetings etc have shown that folks knew of trouble but actively chose to ignore it.

    On top of that there is the whole environmental issues which have removed flood control devices without subsequent information to cities down stream or prevented upgrades to existing devices because the yellow-throated, blue gilled anthrax bug lives/lived in the area. These same folks will then scream when natural disaster strikes and either has more environmental damages from the industry, chemicals, and human civilization that are destroyed in the process or use this to flag wave at the evils of human civilization.

    Comment by Charles — 2/12/2017 @ 10:00 pm

  5. The only sane thing for anyone in low-lying parts of the Feather River basin to do right now is get out. The emergency spillway might breach. It might not. We won’t know until the water level falls low enough that the crisis has passed – and you’d have to be a crazy man to stay in the valley, right now.

    The worst thing is: more rain is coming. The primary spillway is severely damaged, and the secondary spillway is basically unusable at this point.

    It’s going to be a long remainder-of-winter for that part of the central valley.

    Comment by aphrael — 2/12/2017 @ 11:05 pm

  6. As I said at the main site … apparently in 2005, when FERC was relicensing the dam, the Sierra Club petitioned FERC to require, as part of the relicensing, that the secondary spillway be encased in concrete. Both DWR and FERC refused, saying there was no risk.

    Comment by aphrael — 2/12/2017 @ 11:06 pm

  7. Aphrael,

    Which goes back to my issue before about the pure negligence of Government. They were advise of the issue and they chose to say there wasn’t an issue.
    It is a surprise to see the Sierra Club on the good side of this, most my experience again up north and watching their actions in the Chesapeake Bay region seems to say that environmental groups are more in the negative about flood prevention systems that aren’t natural (ie wetlands or lowlands or run off dry streams) than they are for actual fixes to man made systems like dams, spillway and canals.

    Comment by Charles — 2/13/2017 @ 12:16 am

  8. The Oroville Dam is listed as owned by the California Department of Water Resources (See page 35 of the alphabetical listing of dams). The Department is responsible for inspecting and maintaining the dam:

    • How does the Division ensure the safety of dams in California?

    The Division has several programs that ensure dam safety. When a new dam is proposed, Division engineers and geologists inspect the site and the subsurface exploration to learn firsthand of the geologic conditions. Upon submittal of an application, the Division thoroughly reviews the plans and specifications prepared by the owner to ensure that the dam is designed to meet minimum requirements and that the design is appropriate for the known geologic conditions. After approval of the application, the Division oversees the construction to ensure the work is being done in accordance with the approved plans and specifications. Following construction, the Division inspects each dam on an annual basis to ensure the dam is safe, performing as intended, and is not developing problems. Roughly a third of these inspections include in-depth instrumentation reviews of the dam surveillance network data. Lastly, the Division periodically reviews the stability of dams and their major appurtenances in light of improved design approaches and requirements, as well as new findings regarding earthquake hazards and hydrologic estimates in California.

    • What does the Division do if a dam appears unsafe?

    We work closely with dam owners to identify and correct most potential problems before they become more serious. When notified of a potentially unsafe condition, we will inspect the dam and depending on the circumstances, we may initiate or require a follow-up investigation. When unsafe conditions develop, we work with owners and their consultants to address and remedy the condition in a timely manner. To minimize risk, we may impose a reservoir restriction limiting the water surface to a level that is judged safe. We may direct the dam owner to implement their emergency action plan (EAP), or request that they develop one in coordination with local authorities.

    The Department that does the inspections owns the dam.

    Comment by DRJ — 2/13/2017 @ 8:13 am

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