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.
This is as of yesterday, very few updates today...
http://pixel-ca-dwr.photoshelter.com/galleries/C0000OxvlgXg3yfg/G00003YCcmDTx48Y/I0000KtZo.CVW_WY/KG-oroville-damage-12866-02-20-2017-jpg
bing
https://www.youtube.com/watch?v=Z0Ij7cD2C8Y
Anybody know who this guy is on this video and if he’s good? If so, could someone ping me on future updates from him?
BTW, did you see this?
“Evacuate now: Nevada dam could break any moment:”
http://www.freerepublic.com/focus/f-news/3527583/posts?q=1&;page=1#1
“Evacuate now: Nevada dam could break any moment:”
It’s a holding pond. It is in the middle of nowhere in the hills. But it could generate 2-4ft of flood water in the area outside of town. I tried finding it on the maps. Following dry creek beds in the imaging to see where this may be. There are a few spots in the hills that may its location but the sat map pics showed everything dry.
They should change the title to “holding pond” instead of alarming people.
“Anybody know who this guy is on this video and if he’s good?”
Others could answer better than I. IIRC I believe he is a citizen journalist local to Oroville. I did find his youtube information had good and fresh information that is/was very instrumental in getting more context than reading a printed story. This update report revealed an important sense to what officials know about the dam & what the immediate priorities are in emergency fixes.
That key information said much - it was key to me on his “context” of explaining commentary of the ES - i.e. his translation of what he heard via official statements. side: it was important to me considering inside information on recent data + pouring through all of the original construction archives, finite element analysis computer simulations (earthquake survivability), extremely detailed hydraulic fluid flow scale model testing & design modifications, and the trail of “decisions” that led to breaking the main spillway & emergency spillway into two entities (the way it is now vs what they originally had planned).
Thank you. The bottom of the spillway looks ready to break off.
That should cut down on the cost of demolition!
Realistically, the bottom will be torn out and replaced. The top will either be repaired or replaced. A good assessment can't really be done until the water is down enough that they don't need to use it for a while. Which also means getting the plant back on line.
The entire chute should be rebuilt. The upper portion is aged and has numerous cracks and patches. Secondly, and most importantly, is a design issue. The slope should be flat rather than a convex curve.
I believe that the shape followed, at least for a good portion of its slope, the hard rock beneath. That’s why the top portion stayed put, and the bottom section is intact. That part in the middle - well, it wasn’t built on sound bedrock apparently.
but you’re probably right - it needs to be rebuilt anyway. Technology has advanced a lot since the 1960s, even if work ethic has not.
Highway 41 road collapse near the entrance to Yosemite
http://www.freerepublic.com/focus/f-news/3527653/posts
What do you make of the issue about the power source for the Main Spillway gates?
Wow. I’m not sure I ever heard of that high a wind at Squaw.
Storm: 10 trillion gallons over next 7 days for CA #LakeOroville watershed ... Posted on 2/21/2017, 11:07:42 PM by Ernest_at_the_Beach
http://www.freerepublic.com/focus/f-news/3527713/posts
In my opinion it is the varying angles of decline that are a factor, if not the factor, causing the spillway failure.
The failure occurs approximately 1,735 feet from the gate.
In the following diagram the blue line illustrates the profile of the spillway and the dashed red lines illustrate the flat portions of that profile. "X" marks the location of the spillway failure. I think it is not coincidental that the failure point is at or very close to the second inflection point.
Here's a close up.
Everyone knows what happens when you drive too fast over a small rise, everyone knows what happens at the top of a hill on a roller coaster - you momentarily come out of your seat. This is what is happening to the water in the spillway. The water is, to whatever degree, flying away from the spillway at the first inflection point and colliding with the spillway at the second inflection point.
The force is tremendous.
According to a Los Angles Times article "the spillway began breaking apart when its gates were opened Feb. 7, allowing 55,000 cubic feet of water per second to roar down the slope." At 70 degrees one cubic foot of water weights a little over 62 pounds. Colder water weighs more, but let's go with 62 pounds. 62 x 55,000 = 3,410,000 pounds of water per second.
According to this November 1974 California State Water Project Bulletin the width of the spillway is 178' 8". I'll leave it to engineers to determine how many pounds per square inch of spillway 3.4 million pounds of water per second can pound. To me it seems common sense, the convex curve of the spillway is the problem.
Excellent summary of the big picture in non-technical language.
Yup, it has been undermined.
Updates:
https://www.youtube.com/watch?v=Nrz-U1yxOWM
Oroville Dam Tues 21 Feb 2017 Update
blancolirio
Published on Feb 21, 2017
DWR wants to stop Oroville spillway flow, doesn’t know when it can
POSTED: 02/21/17, 6:14 PM PST
CA State Parks: Areas Around Lake Oroville Dam Could Remain Closed Through Summer
Tuesday, February 21st 2017, 8:12 pm CST
http://www.ksbw.com/article/anderson-dam-in-morgan-hill/8961786
WATCH: Anderson Dam overflowing in Morgan Hill
Feb. 21, 2017
http://kron4.com/2017/02/21/major-flooding-in-san-jose/
Published: February 21, 2017, 10:16 am Updated: February 21, 2017, 10:18 pm
Dayton residents continue to prepare for flooding after scare
At about 5 p.m. Tuesday, Lyon County officials advise the immediate threat from the retention basin was over. Water was still flowing in the drainages but no property or structures were threatened. No evacuations were ordered.
There was substantial concern of a “Dam Failure” but there’s no dam in the area. Lyon County requested the National Weather Service to activate the Emergency Alert System to notify residents of the potential of flash flooding due to retention basin over flowing. Unfortunately the only category this event would categorize was as a dam failure. The NWS followed the appropriate protocols and Lyon County officials said they are grateful for NWS’ cooperation.
http://www.actionnewsnow.com/story/34554128/lighter-showers-today-but-flooding-concerns-linger
Chico:
Wet and breezy conditions will continue for your Tuesday, but aren’t expected to be as big of an issue as yesterday. The Flood Warning is still in place for the majority of the valley and surrounding foothill, and mountain areas through 4pm on Thursday. The big flooding concern moving forward will be from runoff from recent rain, as the remaining precipitation it expected to die down through Wednesday afternoon. There is a chance for thunderstorms in the valley this afternoon, that could result in isolated areas of heavy rain surrounding that activity. Winds will continue to be stronger than average, but are also expected to diminish compared to yesterday. Winds will be out of the South to 25mph, with gusts to 30mph today in the valley. Some portions of the Sierra could still have gusts to 50mph this morning, but that lowers to 30mph this afternoon.
Temperatures are starting out in the low 50’s in the valley this morning, and in the mid 30’s to low 40’s in most mountain areas. High temperatures will top out in the high 50’s to low 60’s in the valley, and in the mid to high 40’s in the mountains. Similar temperatures are expected through the end of the week.
The next wet system will approach Northern California on Friday. Light precipitation will be possible as early as Friday afternoon, and will last through Saturday. The chance for rain will return on Sunday. Please stay careful if you’re going to be out and about today. Despite the decrease in rain, road conditions could still have major impacts across the region. Mud slides in higher elevations, and valley flooding will still be possible today.
Hi Ray76, Excellent data. However, you might want to reassess your 1735ft inference of the downhill "inflection point" & "failure point" - it is off quite a bit.
The images below identify the original "failure point" to be much further down. Your "Red line" is quite a bit further up the chute from the true "failure point". This is because, over tremendous hydraulic turbulence & cavitation erosion, this caused a progressive "back erosion" failure of the concrete chute to your denotation (red line).
The "blowout" erosion hole started at least 2,039 ft down [not 1735ft] [note: 2,039 ft in linear X axis to match your plot(s)] I believe the "precise location" past the 2,039ft will be the subject of intense engineering discussions in future failure analysis official work/reports.
Heavy Failure analysis discussions have been very intense in other engineering forums. The recurring basis of agreement is a damaging & highly localized cavitation condition originating in the surface of one of the main spillway concrete slabs. How this cavitation hole originated has been stipulated that there was a "slumping" or "slumping combined stress force [via sub-structure failure or a sub-erosion cavity]" on a fracture in one of the concrete slabs. Note: Evidence has linked the failure point/location to a loss of drain flow in one of the many critical drain pipes designed into the chute structure. You can see these "drains" jetting water back into the spillway from the concrete side guide walls from one of the images below.
A missing flow from one of the drains indicates that the waterflow -at that section- has a "damaged or broken drain". Thus, there would be an undesired flow of pressurized water beneath the spillway slabs at that section or localized region. Pressurized under flow leads to erosion scouring. Erosion scouring leads to a void or cavity. A void or cavity creates a non-linearity in the stress/support of the subsurface to the bottom of the concrete slabs. etc.
The net result was a series of factors which came together that caused an extremely damaging non-laminar flow in high pressure conditions. The high pressure conditions, from the flow velocities and the weight of the water, caused extreme cavitation erosion - this would quickly eat away at the concrete (cavitation pitting is known to eat away steel from the implosion forces of tiny bubbles - well known damage in water craft propellers).
It should be noted that even a full linear spillway design (with no curvature) wouldn't be any safer or a better design. The same high flow velocities and tremendous weight of the water exists in both architectures. Only by insuring the integrity of a good "laminar flow" structure, from original construction & techniques and doing good maintenance, will a design maintain its original design integrity.
One highly respect dam design expert, Scott Cahill, had some very enlightening information regarding Oroville's main spillway & issues linked to his extensive knowledge on dam failures. Three of the key issues he noted in detail was (1) thorough & expert level maintenance (2) the Oroville main spillway had too high of an underflow of water beneath the concrete [as he noted by the amount, volume, and velocity of the "jetting" underdrains - this is a significant issue to address to prevent erosion scouring and sub-spillway pressurized leakage] - [i.e. this was an "early warning" that should have been taken action upon] (3) the original construction MUST be thorough on its bedrock/concrete and anchoring stability.
It seems Oroville (dam) failed in all three of these facets. See Post 1521 (green circled area in construction blueprints). There were no drill holes done in the area of the blowout failure. Solid "good bedrock" is observed below the missing drill area - AND - above the blowout, the stability of the spillway, even under tremendous back cutting erosion forces, has maintained a stability. Thus the drill holes above and below the "blowout" failure would infer solid "good bedrock". Oops on item (3).
No public discussion of issue (2), by authorities on the high underflow "jetting" spillage….YET (with the exception of Scott Cahill bravely coming forward). Will "wait and see" on authorities discussing this publicly - A possible future public "Oops" on item (2) (even if by silence).
Maintenance: Scott Cahill is devastating in revealing this matter: i.e. what should have been done, the costs to do it, and the time to do it when dry. Plus, many other news stories speak of maintenance $'s not reaching Oroville, but lavished on other projects & interests. Big Oops on (1).
Distance Forensics (to original "failure point"): See the three images below.
Image shows pre-blowout damage. Note the brown waterflow location above, under, and to the side of the spillway. Also note the "turbulence seam" locations from compromised concrete slabs. NOTE: The location of the yellow jackets of the construction personnel to the left of the spillway…they are across from the access road where there is a man-made junction box on the right side of the spillway (this junction box is in the access road). The X linear distance to this access road location is 2,039ft. NOTE: that the all of the turbulence is below this 2,039ft reference.
Image shows "blowout" damage in the main spillway. NOTE: the access road in the upper part of the image. The junction box is located in the left side of the access road. The X linear distance to the center of this road is at 2,039 feet. Since the first image demonstrates damage turbulence below the access road, the likely "failure point" is further down from this 2,039ft X axis distance.
Green circled location is the terminus of the access road next to the main spillway. The linear X distance to the center of this access road is 2,039 feet.
Thanks for the physics data. This is why a foot of rushing water on a road can be so dangerous and why more people drown in their cars than any other place/area/spot!
“The force is tremendous.
According to a Los Angles Times article “the spillway began breaking apart when its gates were opened Feb. 7, allowing 55,000 cubic feet of water per second to roar down the slope.” At 70 degrees one cubic foot of water weights a little over 62 pounds. Colder water weighs more, but let’s go with 62 pounds. 62 x 55,000 = 3,410,000 pounds of water per second.”
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