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  1. Mick West

    Mick West Administrator Staff Member

    Note This thread was split from:
    It is a focussed thread dealing just with finding and analyzing pre-failure photos of the damage area to see if there are clues as to what happened

    Hard to line up, but it looks like that damage is slightly above where the hole first formed.
    Last edited: Feb 18, 2017
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  2. deirdre

    deirdre Moderator Staff Member

    yea its definitely below that lower bush beneath the tree
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  3. deirdre

    deirdre Moderator Staff Member

    some more commentary by Senior Civil engineer of dwr Dossey, full 2013 pic with credit, ..but no link to the inspection reports.

    [edit add: links to available inspection reports located bottom of this article]


    video of the interviews, and at 2:22 reporter says they viewed the 2014 and 2015 inspection reports and are waiting to receive the 2013 reports to get details on possible erosion issues mentioned by Dossey.
    Last edited: Feb 11, 2017
  4. Here are the inspection and damage photos better registered. It does appear that the failure is related to the area of prior concern.
    Oroville Spillway.
    Last edited by a moderator: Feb 11, 2017
  5. deirdre

    deirdre Moderator Staff Member

    i think youre off by a slab (although i dont know how long the slabs are so not sure it matters all that much)

    Attached Files:

  6. dario martinez

    dario martinez New Member

    I sent my engineer friend this post and this is his response:
    Man! What a good source. Excellent if fact. I enjoyed it, got me thinking.
    We Hams, we know about standing waves? These would be Long wave, subsonic waves. Meters in length.
    The start of the spillway in the feed, the power terminator is the speed bumps at the bottom. There's Kilowatt, (Megawatts) of acoustical energy emitted as noise.
    To examine the entire spillway, it looks like a Transmittion line. Energy feed, Energy terminator, containing a lot of Raw power in between.
    Frankly, I think the failure was caused by resonance. Something not planned for? Not cheap construction, or some terrorists. Time will tell? Hope it wasn't just a big leak.
    I know acoustical wave travel backwards in a flowing column of water. If they are strong enough, they will reverse the flow, and I can prove this. I can well imagine the vibrations building up in a rigid flat plate until it breaks. I'm sure, they must have a seismometer there.
    Wonder what seismic data, during the course of failure, would revile? Bandwidth of the detectors?
    Super link. Sign up? Mick West sounds grounded.
    Last edited by a moderator: Feb 11, 2017
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  7. deirdre

    deirdre Moderator Staff Member

    the dam? the federal government according to articles (which are all over the internet) inspects the actual dam every 5 years. I imagine inspecting the concrete is part of inspecting. you can look at the inspection reports i linked in a previous post and google "FEMA dam safety" to read about dam inspection protocols. maybe google "concrete maintenance".

    [edit: hmm this link says both feds and state inspect every year.
    here's a fun old video of the construction 50 years ago.

    Last edited: Feb 11, 2017
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  8. MaryL

    MaryL Closed Account

    Last report I reviewed was 2010, so do you know where the 2015 report might be located? Thanks for the video!
  9. deirdre

    deirdre Moderator Staff Member

    heres links i found.. scroll down and they are on the left side. probably just state reports, i didnt read them myself.
  10. Mick West

    Mick West Administrator Staff Member

    Last edited: Feb 16, 2017
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  11. Tom W

    Tom W New Member

    Very interesting comparison. A minor problem gave the water something of a "handle" with which to unzip the concrete. Once the hole was open, it spread rapidly.
  12. whoosh

    whoosh Member

    This site (link) overlays "before and after" orthorectified aerial photos of both spillways, full length, and presents them with a slider enabling convenient examination of their differences. Well Done.

    Edit: And I see that Mick just inserted the same slider tool above, on a close-up of the full photo.
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  13. Alex Thomas

    Alex Thomas New Member

    First post, but have been lurking (and learning a LOT of fascinating info) for a couple weeks now.

    In regards to your post and the photos above - I'd be equally concerned about the dry areas below certain joints between slabs. While some water (at a VERY low speed) might just divert across a joint for a few inches, it's unlikely for it to vanish like that, right? I mean many areas are just DRY.

    Is there a wider view of the spillway at a low flow rate like that which shows any other dry areas?
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  14. Mick West

    Mick West Administrator Staff Member

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  15. stuart little

    stuart little New Member

    oddly enough thats exactly where the drains start to drain.. nothing draining above that point....
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  16. Mick West

    Mick West Administrator Staff Member

    Here's the spillway on Sept 5, 2014. This is a few hundred feet above the actual damage section. Note a variety of cracks and repairs

    Here are similar cracks just below the hole

    Last edited: Feb 16, 2017
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  17. Pozzolith

    Pozzolith Member

    That 'noisy shadow' is from adjacent trees. I've been thinking about that for the last couple of hours and had tried to find the 2013 photos, but the one's you've posted are much better.

    Tree roots.

    Anyone who has a concrete driveway with adjacent trees knows what eventually happens. You can see that the cracks were patched with some type of grout. Perhaps the roots, if that is indeed the cause, grew to the point of causing the slab to heave? And could the underlying root system given any infiltrating water a channel to travel along and allowed washout to occur?
  18. Pozzolith

    Pozzolith Member

    The evenly spaced lines are 'control joints' that are common to concrete highway slabs the world over.

    Placing Joints in Concrete Flatwork: Why, How, and When
  19. CRM114

    CRM114 Member

    I ran across this odd tweet:


    Photo shows a crew examing the area that failed. Drains appear to be weeping. The drain that has been noted to be dry recently is also dry here. Also, the slab appears to be weeping, indicating the underdrain may not be working in this area.
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  20. Pozzolith

    Pozzolith Member

    October 7, 2009

  21. Scott Gates

    Scott Gates Active Member

    That is likely crack repairs being done - and that is what the "seeping" could well be ...
  22. JCL

    JCL New Member

    Found this while digging around, it's a postcard of the construction. Is it me or does it look like 2 sections split with a line in the neighborhood of the initial compromise last week? I can't tell exactly where the line here compared to the compromise last week, but it looks close. Did they pour in these stages as it looks like the non-poured up top is about as long as the bottom 2 sections? It's not a great image so hard to tell. Any other thoughts? Thank you

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  23. Mick West

    Mick West Administrator Staff Member

    The google Earth image from 4/14/2015 shows a lot of patches on the join at the top of the original failed area.
    They actually look like rectangular patches, like someone sawed out spalling concrete to make a better patch. Like
    You can verify this is the join by the pattern of white repairs on the join above.
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  24. deirdre

    deirdre Moderator Staff Member

    looks like a little bit of a dip to me too.
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  25. Mick West

    Mick West Administrator Staff Member


    Hard to tell, I'll let you know when my postcard arrives. It might just be a crease or mark on the postcard.
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  26. Ethan O'Connor

    Ethan O'Connor New Member

    Nice find. There are two other areas with similar appearance in that image. Check out where the next one upstream is:


    That's very close to if not coincident with the current upstream failure progress.

    The other place you find these is about 500' down from the gates:

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  27. Much of the rock missing at the base of the spillway in this photo, light gray areas missing.

    is of a lighter gray outlined in green in the postcard photo. Also note the strange darker area of the spillway right where the blowout occurred (circled in red). light gray areas anotated.
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  28. Scott Gates

    Scott Gates Active Member

    From Micks 2012 pic above ... can seen the left side (looking at pic) drain appears to have been weal flow and/or inoperative since at least 2007 ... we can see the appx top of the start of the damage area and some cavitation occurring over it.

    And on right we can see what the drain pipe looks like (this would be one below the inoperative one) ... that it comes from under slab

    A guess is maybe water is supplied to these drain pipes when spillway flow is initiated - perhaps a pipe along each side of spillway that runs from top ... and the discharge topside creates a negative pressure in the drain pipes to draw water out of the subsurface?

    If that is the case - that these pipes are charged with water from above - then a non operating pipe could be broken and leaking that water under the panels

    Credence is led to the theory these drain ports and charged with water by the fact that the large blowout in sidewall and resultant erosion killed flow from all drains below it. Which is also supported by fact a small wall breach initially did not kill drains on left side, but when a larger wall breach occurred the lower drains did stop working ...

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  29. Mick West

    Mick West Administrator Staff Member

    The TerraServer site has a series of higher resolution images of the area:✓&search_text=39.53986, -121.49537&searchLat=39.53976&searchLng=-121.49537&lat=&lng=&bbox=&center=

    The patches/damage show up in a variety of photos

    But of particular interest is this one labeled 2016-05-02


    Appears to show some turbulence at the spot where the damage occurred.

    This type of turbulence also occurs in one other spot near the bottom.

    Like the hole area, this lower turbulence area also shows a quite large repair

    This lower damaged area was still visible after the upper hole formed, and was visible during the first stoppage:


    Last edited: Feb 18, 2017
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  30. CRM114

    CRM114 Member

    Amazing find. Such turbulent areas (spalled concrete or lost patches of previous spalls) lend creedence to the cavitation theory.

    Cavitation could quickly enlarge these imperfections. I would point out that cavitation might not be the root cause. One has to ask why these spots require work in the first place. The drains / poor rock being discussed here could still be the ultimate root cause.

    Inspecting the spillway "at a distance" in 2016 and 2015 looks bad in light of this photo.
  31. deirdre

    deirdre Moderator Staff Member

  32. Mick West

    Mick West Administrator Staff Member

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  33. CRM114

    CRM114 Member

    Great new thread:

    If anyone with access to the CA DWR site could download full versions of these (my account still has not approved):

    and post a closeup of the drain outlets, it would be a comparison of drain flow then vs. now. This is the only event I know of where spillway flows were higher than Feb 2017. These photos show a 150,000 cfs flow.

    These might show whether drain flow has increased over time.

    Edit: FWIW, here is the best I can do w/o the ability to download the full res pic:


    Drains are clearly flowing pretty good, but at a what looks like less flow than a few days ago. This with 50% more flow in the spillway.
    Last edited: Feb 18, 2017
  34. Mick West

    Mick West Administrator Staff Member

    Going back to 1969, via

    I was interested based on the "Postcard" image if there's any indication of a line across at that point, but it all looks fine as far as we can see with this photo.
  35. DeejayB

    DeejayB New Member

    The bare rock at the end of the spillway indicates considerable erosion; earlier photos show this area as well covered. I gather then that the spillway termination is not protecting the river and channel as it should. Reconstruction of the spillway should include upgraded exit to disperse the energy of the water flow.
  36. CRM114

    CRM114 Member

    Yes. Roots from that tree could potentially go under the spillway wall. From FEMA:

    These words apply to the spillway too. The roots can shorten the distance between the source of high flow in the spillway to an exit point.

    I would add this as #4 to this list:

    Which came first, the erosion of the bank outside the wall or did failure of the spillway slab force water under the wall, or was it water splash? Could a tree root have made it easier to scour under the wall? Probably.
  37. Mick West

    Mick West Administrator Staff Member

    2007 USGS image:
    • Entity ID:1220548_SAC028C049
    • Acquisition Date:01-JUN-07
  38. Mick West

    Mick West Administrator Staff Member

    A bit off topic here, but from the historical images the flow pattern over the rocks not that different in 1969. I suspect the first few large flows simply washed away the loose rock, and it has been pretty much unchanged for the last 40 years.
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  39. SFX

    SFX Member

    Source of that photo?
  40. deirdre

    deirdre Moderator Staff Member

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