Posted on 02/12/2017 4:26:47 PM PST by janetjanet998
Edited on 02/12/2017 9:33:58 PM PST by Admin Moderator. [history]
The Oroville Dam is the highest in the nation.
Here are some points to further explore the evidence.
(1) If it was a pour to level to grade, then there should be anchors protruding from the bottom of the pour. This is how the blueprint designs identified "concrete to grade". Yet there is no sign of any protruding anchors.
(2) The construction photograph reveals that there was an aggregate layer compacted and leveled "to grade" before the concrete slabs were poured. Strong evidence is revealed in the diagonal "percolation seam" (i.e. if it were concrete in the picture, the seam would not be diagonal, plus the color hue does not match concrete coloring of the keyed chute blocks).
(3) This infers that there was a layer of aggregate & fines under the original slabs. The BOC confirms this in their first report of "filling" material between the subrock and the slabs.
(4) A smooth layer of aggregate and fines would be a much better suitable foundation to lay the frangible (fragile) Vitrified Clay Pipe Drain upon. Otherwise, laying the VCP pipe on rough rock or even fill grade concrete would risk cracking of the pipe. (5) IF sections of "fill grade concrete" were present, the construction photograph does not reveal this. You should see areas of discoloration. The image is uniform in hue up the main spillway. HOWEVER, the image does not show the final upper sections of the Upper main spillway. That is where archive documents identified "less than competent rock" where they had to resort to "chain link", "pigtail anchors", and rock bolts. This could explain the larger sections of potential coring depths of concrete in the upper main spillway.
(6) Then the key puzzle question is the seam of the upper slab section mating with the lower larger block of concrete. It is very clean. If there were the "aggregate & fines" that provided the original base to the slab pours, where did it go? Most likely it was washed away. OR the slab pour was able to penetrate the aggregate with the fluidic part of the concrete grout to bond with the "fill to grade concrete" below. This would make the bond junction less competent and more likely to split away from the forces that transported the chunk down the spillway.
(7) There is a telltale "hole" in the slab that looks to be where a drain pipe was located. The hole looks too small for a normal sized drain. But the hole could be an artifact of the drain pipe falling down & into a "fill void". The hole may be the leftover of the polyethylene plastic & some drain rock trapped in the slab pour grout.
(8) It is clear that the longitudinal drain was completely inoperative at the east sidewall drain near the failure area. Either the drain was sealed or the longitudinal drain broke away & water flowed under the slabs down slope or flowed into a subterranean channel.
(9) The fact that DSOD inspectors found loud echoing voids from sounding reveals that "repairs" (known to have been repeatedly performed in the blowout failure area) "best fit" that grout material was being emplaced. The pre-failure images reveal a large seam void was cavitating prior to the blowout. We don't know if large "repair holes" were present at this area (evidence gone), but the BOC did state that this was observed in other areas of the spillway. A large "repair hole" would facilitate pours of concrete to fill a large void.
(10) Note: consider unconfirmed: What tends to tie some of this together is insider tips from people doing repairs reporting of 6 foot voids and 4 foot voids being filled. These tipsters have come out of the woodwork but don't want to go public. Thus, evidence has to be pieced together. Hopefully, the forensic team will not be inhibited and will investigate all clues available.
Anyone who has been following the information and excellent analysis on this thread is aware that maintenance on the Oroville dam has been appalling (NOT just on the spillway).
It is clear that the DWR is covering this up.
Since the same DWR is in charge of many other dams in California, it seems certain that other dams in California are also at risk.
Thus far, however, I see very little to indicate the people of California have figured this out.
If not for this thread, we wouldn’t have had an inkling of the danger our waterways and reservoirs are experiencing. Following the posts here are difficult to say the least for a layman. But we’re hanging in and getting to the real data behind the spillway overflow. Many thanks to the researchers for giving a damn!!
ER333,
This post made me sick at heart and I had to close it for a couple of days. Our magnificient manmade dam, a stunning engineering feat of the 20th C. allowed to fall apart by the mindless, poorly educated, anti-progress leaders of the State of California. You have uncovered the answer to what went wrong. No wonder you ended up ill last week. This is like seeing a starved animal chained to a small area, unwanted, neglected, alone to die. My feeling is the same in either case.
Thanks for the additional information. The seam between the “slab” concrete and the concrete that was under it is very straight. Almost like a finish layer was poured atop a smoothed finish layer.
And I agree, no evidence of any anchoring below the big hunk of concrete. But the way that they stuck together, would that indicate that there was anchoring between the top layer and the piece of fill below? I suppose that would easily be determined on inspection, and I somehow doubt that there was It’s just that they stuck together so nicely.
There’s been so much information in this thread that I’ve forgotten a lot of the previous posts. To anybody joining late, take a gander back in the thread’s history. There’s a ton of information there.
The Division of Safety of Dams (DSOD) & DWR being in the same "house" can be like "trusting the monkey with the banana". There could be great temptation.
If DWR/DSOD loses trust with the public at one dam, how do they assure their reputation at all dams?
Two Dam districts, Santa Clara [2] and Irvine [7] both put out professional public literature/information that is intended to assure the public of the quality of the safety of their dams, noting the DSOD careful inspections and thorough assessments of the stability of dams. One of the most important instruments to assess the internal stability of a dam, especially just after a seismic event, is using internal water pore pressure sensors called Piezometers [1][3][4][5][6].
Any sudden jump beyond design parameters, or if water pressure is detected in a zone layer that it shouldn't be within, the dam operators could immediately determine the risk to the dam or if an internal unexpected problem has developed (such as a "through the dam" flow or threatening leak).
DSOD & DWR have chosen to slice the instrument tubings to the (50+) piezometers as they aged and stopped giving meaningful data [8]. Yet they came up with the bright idea of measuring seepage in three places (toe & side Gallery drains) along with settlement survey markers to replace Piezometers. Well, FERC has been asking and asking and asking for DWR to install new Piezometers at Oroville dam [9] (latest in 2016). Even a brave DSOD Inspector noted that just a couple (one in the core zone and one in the downstream Zone 2 transition layer would be useful). Yet DWR has done nothing. Nothing to replace the original 56 Piezometers carefully embedded in an array from bottom to top of the dam. They have zero functional piezometers working today. They have zero ability to assess the internal health of the stability of the dam which all of the other dams around the world consider as critical sensors.
So they have no way of determining if there are internal leaks. Yet they assure the public "when rain falls....then the grass grows", or don't worry, "it's a natural spring" (causing the green wet seepage area).
Even their own DSOD Inspection reports reveal that they have stated in these reports that the Greening Area Seepage is from water coming from the reservoir. Thus their PR misdirection regarding the source of the Seepage area is provably conflicted.
Eventually, something is going to break badly in a way that they will not be able to continue to "spin" is from "Climate Change" or is from "running out of oil", or you get a "flat tire". Something that will cause the veil of CEII secrecy "hiding behind" to where the public distrust is so high there will be demands for new operators to be put in charge.
DWR knows this. Their whole existence rides on current events. But the ultimate existence that should be of the highest importance is not "how to look good", it should be "how to protect the lives of people, property, and the welfare of the state".
Here are reference links that document and back up the above:
[1] Instrumentation and Monitoring of Dams and Reservoirs (piezometers, earthquake, slope stability assessment)- www.eolss.net/Sample-Chapters/C07/E2-12-02-06.pdf [2] Dam Seismic Stability FAQ - Santa Clara Valley Water District (piezometers, earthquake, slope stability assessment)- www.valleywater.org/DamSafety/SeismicStabilityFAQ.aspx
"How does the water district monitor its dams to ensure they are safe? - The water district monitors its dams visually and with instruments installed in the dams. In 2005, the water district created a formal dam safety program, which includes dam surveillance and monitoring. The water district uses a number of instruments to monitor its dams. Internal piezometers measure the dam’s internal core for water pressure, much like a person monitors their blood pressure. Pore pressures determine how the water is flowing through the dam. This is supplemented with seepage monitoring downstream of the dams. Inclinometers measure deformation, or a change of shape within the dam. The water district also uses survey monuments to check on the movement of dams on the surface. In addition, water district staff, the California Division of Safety of Dams and Federal Energy Regulatory Commission conduct annual inspections of the dams."
[3] Dam safety & Safety Devices - piezometers - phreatic surface - stability assessment - https://www.slideshare.net/TusharDholakia/dam-safetyandsafetydevices1
[4] Dam Safety Instrumentation - piezometers - earthquakes https://www.researchgate.net/publication/276268760_Dam_Safety_Instrumentation - AJER-Bamne and SS valunjkar June 2014.pdf
[5] Dam safety at BC Hydro fact sheet- Dam safety instrumentation includes - 3,000 piezometers measuring water levels in slopes, dams and foundations, Earthquakes,- https://www.bchydro.com/news/press_centre/news_releases/2014/dam-safety-at-bc-hydro.html
[6] Facts about Dam Safety at BC Hydro - International safety standards are met by regular monitoring, rigorous inspections - piezometers, slope stability, earthquakes - https://www.bchydro.com/news/press_centre/news_releases/2014/dam-safety-facts.html?fixZoomMobile=true
[7] Irvine Dam Safety Program - Irvine Ranch Water District Dams Are Safe - DSOD has several programs that ensure dam safety. - Piezometers are used to measure ground water and other fluid pressure levels- http://www.irwd.com/construction/dam-safety-program
[8] DSOD Safety Inspection report Feb 8, 2011 Photo 5. "The Piezometer tubing bundle in the S-Block continues to seep."…"A seepage collector pan is visible in the lower foreground".
[9] DSOD Safety Inspection report Sep 27, 2016 page 4. "An incomplete FERC Part 12/DSRB recommendation states that "…a plan for long-term monitoring of the phreatic surface within the dam embankment needs to be developed and implemented." "O&M is working with DSOD to develop a course of action"
That is the most interesting facet. One thing is for sure, the seam junction is "very clean" to have such a condition. I have run across conflicting "as-built" verses the original blue prints (such as the lateral transfer bars between slabs).
Here's one for you. The original anchor bars, which would have been protruding below the original slabs & into the highly erodible material that washed away into this very large void = This is what forms the "tight bond". The anchor bars are now attached to the "fill void" blob instead of the original highly erodible material. It's possible that the clue of one or two of the anchor bars are hidden in the shadows (underside).
Given this condition, the block would tumble in the harshest conditions and would stay together.
Good job! way to "stick" with this puzzle!
Hi EarthResearcher333.
I apologize if you have found some of my posts annoying. That’s not my objective. The most robust explanation for any phenomena is the one that can sustain the highest level of scrutiny. I have offered some alternate perspectives that may or may not be valid, and are certainly subject to scrutiny, as you have done here. I will attempt to refrain from euphemisms such as “sharpest crayon in the box” if that bothers you.
I agree with all 4 of your points in post 3714.
As to your last point, IMHO a key reason DWR doesn’t act upon recommendations of DSOD is based on the acronyms themselves. DSOD is the Division of Safety Of Dams, which is just one of many divisions of DWR, the Department of Water Resources. A Division of a Department cannot effectively regulate it’s parent organization. Engineering staff of both DWR and DSOD (within DWR) share the same job classifications and promotional opportunities. It is unrealistic for an engineer in DSOD to come down hard on DWR knowing that they may be promoted there next year.
DSOD and DWR need to be separated. I don’t think anyone on this forum would disagree with that, but there’s the question of what a more effective regulatory structure would be. Other states must do this differently.
Hi EarthResearcher333.
Regarding issues you raised in post 3717:
LIDAR
The LIDAR used for the “Google car” and many other autonomous vehicles has a stated accuracy of 2cm http://velodynelidar.com/hdl-64e.html , although it does sample millions of times a second, yielding a point cloud resolution better than that for flat surfaces like roadways. Measurement of the large cobbles on the upstream slope of the dam would be noisy, but this could be partially mitigated by oversampling. As you say, the grassy downstream slope would be more of a issue, especially with the Green Spot grass at varying heights.
However, I think such a point cloud resolution should be sufficient to investigate if there are substantial settlement discontinuities across the dam. This would not have the resolution of InSAR, but would be faster/cheaper/more available for a preliminary investigation. Either measurement technique would have to tie into the same survey monuments used for the 1975 DWR Settlement Report cited in post 3624 (or others as available) to determine the past time rate of settlement.
Microprocessors
I suggested the use of an array of microprocessor based moisture sensors to determine if the Green Spot moisture is correlated with reservoir elevation. These are COTS items commonly used in California during the drought - simple and cheap enough that they can be quickly installed. To me, the most critical question is “Dose reservoir water seep through the face of the dam”, and these embedded micro controllers would help determine that question one way or another.
I also suggested that some type of access to instrumentation be embedded in the new spillway as it is being constructed so as to better diagnose problems before they manifest. In lieu of dragging chains over the spillway in the hope that a trained ear will pick up subtle changes over the years, perhaps it might be better to have embedded microphones detect any acoustic changes as a function of spillway flow? My post was more concerned with the types of detection that might be useful, rather than how to write C code to collect the data.
Lighting can fry any outdoor electronics, but that’s not real common in that area of California. However, critical instrumentation should be accessible and replaceable if it fails for any reason.
Hi EarthResarcher333.
Re post 3718:
You have a point and I rescind the claim that the concrete “chunk does appear to be from one of those extra thick sections”. I don’t know what part of the spillway it came from.
My point was that most smaller chucks of concrete got washed away, and that one didn’t, plausible due to it’s weight and thickness. It did certainly enter my mind that this thickness could be do to post construction “void filling”.
Another non-starter with LIDAR is that you cannot tell a differential settlement progression from a single pass at a single date & time. There has to be a period of time elapsed sufficient between samples to get an accurate assessment reading in an "interferometric" comparison of the two.
AS the original reason for bringing up "what to do" in the most effective way to discern information on the Green Wet Area, satellite InSAR data may already be available in mapping runs from years prior. If so, another single mapping run would provide the two samples to compute the precision interferometric results.
Of course, any survey data of the dam would be useful. But this depends on how many monuments are being sampled, where on the dam, and how accurately. There was documentation I've run across where DWR was debating the issues of portable GPS units (error bars in accuracy). If they have been using these systems, the ionospheric scintillation and post processing errors could degrade the precision of a "differential" assessment.
But one of the more important tests that could be performed is TIR/FLIR. It would be able to quickly identify if there is a thermal heat sink of moisture/seepage deeper below the Zone 3 layer. Not only that, it could give a mapping pattern to the source(s) and extent of the thermal heat sink.
The TIR/FLIR is non-invasive, aircraft capable, and would give swift information to the full area of the downslope surface of the dam. No piezometers needed for this first assessment.
The challenge with using Piezometers at this moment, is that they require a careful construction operation to emplace. DWR should have had instruments in the ground years ago. Right now they don't have the luxury of referencing instruments that are not there. The other question is how many and what location(s) should these be placed. Remember, the Zone 3 fill backside of the dam should have zero pore pressure. So all of these carefully well drilled, grouted, and sealed emplacements would be in a part of the dam that would be just for this Green Wet Area investigation. The sensor may be affordable, but the engineering construction & emplacement is very expensive and time consuming (if done on the downslope face).
If you are wondering about "does reservoir water seep through the face of the dam", I'd suggest you go talk to DSOD inspectors. They have written this fact into their report. So you don't have to take my word for it. This DSOD report was when there was a severe drought with 81 straight days of no rain - yet they identified seepage still coming out of the wet area. If this data is not acceptable to anyone as extremely strong evidential proof (from DSOD themselves in a personal inspection AND stated "from the reservoir"), then I don't know that if you'll ever convince that "anyone". Best not to discuss it with them at all.
Spillway: The first defense is a good offense. Build it right with a high factor of safety. The BOC has already had DWR work to get a piezometer into the upper spillway area (in the recent repairs). I'm not sure if it is already installed & running or if it will soon be operational. Piezometers are useful in detecting water where it shouldn't be, or detecting water pressures that are unexpected. There are sensors that may assist in monitoring the massive area of the spillway. This is not disputed. However, the choice of the technology should be with wisdom as electronics can be poorly designed without the user being aware of its FIT rate or MTBF (Failure in Time or Mean Time Between Failure).
The modularity, serviceability, and accessibility are important. But the wiring & power is critical to insure integrity for a long span distance (3000+ feet). That is where the dv/dt fast transient earth voltage/current gradients may couple into electrical sensory wiring systems. Fiber optics provides an isolation to this effect, but you have to have good & reliable power supplies at the tx/rx repeaters & transceivers.
In critical Hospital operating rooms, in doing heart procedures such as atrial fibrillation ablation, they have multiple computer systems that overlap in their ability to detect & monitor conditions. This makes it fault tolerant (i.e. if the old Windows operating system blue screens on you the patient won't "blue screen"). [btw= I've been through 5 ablations & when wheeling into the operating room I immediately saw the computer array & screens - then asked what OS were they running & what happens if it "blue screens" - they laughed knowing what I was asking and assured me that they had redundancy - yes, their systems sometimes crashed back then]. So too should be the strategy in monitoring.
I brought up the C++ code to assembly language to code branch anomalies as a real life example of rare "glitches" in microcontroller code. I have spent decades in this field. It is only getting worse at times just as I mentioned in the EEPROM case where the engineers were oblivious to the soft error rate risk to the floating gate charge leakage loss (soft bit error).
The key is to leverage experts. Just as you are doing good "out of the box" thinking, when coupled with "what if's" with "experts in the field", that is when the continuing innovation occurs. A good tip: The best experts are the ones who can tell you every conceivable way something can fail.... :-).
I do appreciate your input and discussions. Thank you.
They’ve added quite a few pictures since the last time I’ve posted the link.
They’re using low-level explosives to break up the spillway. Someone left their lunch cooler on the concrete in image 1. :)
Some more new pics. Looks like they’re making good progress on the concrete demolition. Also, some good shots of the batch plant.
It looks as if they’re starting to remove some of the lower section of the lower spillway, but it also looks like they’re trying to set up a clean straight cutoff on the upper spillway. This is based on observing the Dam Cam linked above.
Not exactly Oroville-related, but Juan Browne, who has brought us some news narrative and video from the dam, has a short tribute for Memorial Day....
https://www.youtube.com/watch?v=24FWvFBBGec
A Chico-ER photographer was able to catch the right moment where the plunge pool erosion found a direct pipe inlet opening to a longitudinal drain. If these drains are near the 16 inch diameter estimates that have been tossed about, this is what a "full on" pressurized longitudinal pipe can do.
Pretty impressive flow. Surprised the pipe sections didn't separate from the pressure.
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