deirdre
Senior Member.
I don't understand why you are saying this. What am I misunderstanding about the "disaster declaration approved" notice?That doesn't mean there is any federal money.
I don't understand why you are saying this. What am I misunderstanding about the "disaster declaration approved" notice?That doesn't mean there is any federal money.
There has only been an EM declaredI don't understand why you are saying this. What am I misunderstanding about the "disaster declaration approved" notice?
The key component is debris removal and emergency protective measures. No repair is mentioned.I don't understand why you are saying this. What am I misunderstanding about the "disaster declaration approved" notice?
yea but if they had said to y'all prior to the hole issues.. "This spillway has serious issues, we need a major and complete repair to update it to current standards and prevent long term future failure" you'd be facing almost the same pricetag (minus debris work. plus excavation that the collapse provided free of charge) you are now.
At least this way the feds are helping you out more than if you took care of your infrastructure yourself in a timely fashion.
What else has not been monitored and maintained? Could thorough monitoring have caught the issues that ultimately caused the spillway failure and allowed for timely repair or partial updates, instead of the current total replacement?
I see. I thought that fell under the 'hazard mitigation' section.No repair is mentioned
Press conference shows "concept" plans for new spillway. The plan for the emergency spillway in particular is ambitious. It also means removing all the concrete they've put (slopped?) in to date.
Source: https://www.youtube.com/watch?v=QAY-4-NeB18
has some images from the conference.
So, what happens when the Emergency Spillway wall to the left (looking toward the lake from dam) of the weir is overtopped again and its base gets eroded? Anyone seen anything about what DWR has planned for that area? If the weir needs work, it would seem to me that the wall needs more.
See:
http://www.water.ca.gov/oroville-spillway/pdf/2017/a3186 Oroville Spwy Recovery_v5.pdf
So basically erosion would be anticipated below the downstream cutoff wall, but the cutoff wall (set deep in the bedrock) would prevent that causing any structural problems.,
Thanks, but all this relates to the weir, all three bullet points mention it. Have they said this plan will extend the entire width of the Emergency Spillway, all 900 or whatever feet of it?
Not that it's a wrong thing to do, but they sure are spending a lot of expense and effort to shore up an emergency spillway which they are determined to never use. It feels like their investigations haven't increased confidence in the original weir stability.
Not that it's a wrong thing to do, but they sure are spending a lot of expense and effort to shore up an emergency spillway which they are determined to never use.
Yes (the dry season typically has already started by now, and we essentially get zero rainfall in CA over summer). But inflows won't stop when the rain stops. There's much higher than normal snowpack in the Sierran watershed behind the dam. The spring thaw lasts way into the summer in the mountains. I suppose it's known what typical inflow rates are from a given snowpack, but if the weather happens to get atypically warm fairly soon up there? Can they predict runoff rates from the thaw as reliably as we can predict that it essentially doesn't rain in CA in the summer? I imagine it'll take some time for the Hyatt to draw lake levels down at 10-12 cfs outflow when all that spring/summer melt is coming in.Once you get to dry season, California is super dry. The Hyatt will remain running. Once inflows stop they will draw the lake well below the 835 level..
It's impossible to 100% prevent the usage of the emergency spillway. We are probably towards the end of the rainy season now, but if there's a strong series of storms next season (2017-2018) then it might be needed again.
It was known 50 years ago that top layers of rock were incompetent. The building standards back then were definitely less stringent.
The standard at that time was to remove incompetent rock until you get down to bedrock, then build up from there. The standard nowadays is to go 4 feet down into bed rock, then build up with concrete. This 4 feet allows that base to have downhill push against solid rock to keep the structure from getting pushed off its base. Otherwise you are just relying on the friction weight of the structure and the weight of the incompetent rock.
Looks to me after a close read of his article that the good UC Berkeley Professor plagiarized a lot of his report and presented pictures that were also posted on this MetaBunk .org forum over the past couple of months on the subject.
http://documents.latimes.com/report...ance-defects-oroville-dam-emergency-spillway/
One that stuck out like a sore thumb was page 18/11 (18 of the PDF, page numbered 11) which had the following picture:Looks to me after a close read of his article that the good UC Berkeley Professor plagiarized a lot of his report and presented pictures that were also posted on this MetaBunk .org forum over the past couple of months on the subject.
http://documents.latimes.com/report...ance-defects-oroville-dam-emergency-spillway/
Is there another version of that document that has sources listed? If not, it might be interesting to see what UC Berkley's position on plagiarism by their professors is...
There are a couple of things that I hadn't seen (like the lower left (when looking up the spillway) slab rotating downhill and the left edge separating at the wall) but most of it has been hashed out on here.I have to agree! I've been lurking for a while on this forum and whilst consolidated, nothing new was mentioned that hasn't already been posted here. Thanks to the contributors to the forum, it's made for very interesting reading.
One that stuck out like a sore thumb was page 18/11 (18 of the PDF, page numbered 11) which had the following picture:
That appears that he took sweepleader's picture and added two text boxes:
Is there another version of that document that has sources listed? If not, it might be interesting to see what UC Berkley's position on plagiarism by their professors is...
There are a couple of things that I hadn't seen (like the lower left (when looking up the spillway) slab rotating downhill and the left edge separating at the wall) but most of it has been hashed out on here.
Aaron Z
True, the original photo is from the DWR, but the additional lines should have been credited to sweepleader/Metabunk or he should have redone them with his own lines (I am fairly certain some of the other annotated pictures also came from here, but that one stuck out like a sore thumb).Well, in truth, the image is a crop from a DWR photo, only the colored lines are the work of SweepLeader, but I read the entire report and kept seeing all these photos and concepts that had been built here through our discussions.
I was humored - seems we at least have a professional who agrees with our armchair work.
Brad
I emailed the Center for Catastrophic Risk Management at UC Berkeley about this and got the following response (quoted verbatim from the email I received):
Aaron Z
Extensive photo documentation (annotated) of FCS in this document by retired UC Berkeley civil engineering professor, R.G. Bea, published by latimes.
http://documents.latimes.com/report...ance-defects-oroville-dam-emergency-spillway/
He says something more than that, including that cracking of the spillway deck over the drain system shows that there was inadequate depth of concrete used, that the main deck fracture is directly on the line of one such drain and that the wrong standards were used in regulators' periodic assessments of the spillway's condition. In any case, DWR has now been drawn into giving a partial response to Prof. Bea, which is reported here:OK, so he thinks there was erosion under the slabs, and the massive failure was due to slabs being lifted (and destroyed) by the water flow. Will be interesting to compare to whatever the official report decides.
OK, so he thinks there was erosion under the slabs, and the massive failure was due to slabs being lifted (and destroyed) by the water flow. Will be interesting to compare to whatever the official report decides.