Emergency: California’s Oroville Dam Spillway Near Failure, Evacuations Ordered

Breitbart ^ | Feb 12, 2017 | Joel B. Pollak1

[Grampa Dave]

Thanks for the work both of you have done with this issue.

Pray that the workers and engineers are successful in getting the dam past the rainy season and snow melt.

[EternalHope]

Thanks for the great work you and the other contributors continue to make to this thread.

We are in a much needed lull and the media has gone back to sleep.

I’m impressed with the amount of rubble they have been able to move since shutting down the spillway. It’s also encouraging to see the generators slowly coming back on line.

However, it is certain to rain again and the snow is certain to melt. It seems certain the spillway must be used again this spring, quite possibly for several MONTHS straight.

We all hope the emergency repairs they are still in the process of making will hold up. Although I’m not a civil engineer, I know a bit about how to build things and how to find out if they really work (my undergraduate engineering degree was in a specialized area of electrical engineering).

In this case we have a shocking level of deferred maintenance, apparently flawed original design, and a patchwork of desperate emergency repairs to make up for it. The list of unknowns in this repair is so long that every engineer I know would expect something unforeseen to happen when it is put to the test.

What they have done WILL be put to the test some time this spring. The odds are very high that something unexpected will happen when it is. The REAL test will be how successful they are responding when it happens.

Based on what I have seen once they finally got serious about things, I suspect they will also overcome whatever unexpected setback is coming. I was not so optimistic two weeks ago.

[janetjanet998]

outflow has jumped to 10300

@CA_DWR: Oroville Dam primary spillway repair plan expected in coming weeks, with construction to begin in couple months @kcranews

[EarthResearcher333]

"my undergraduate engineering degree was in a specialized area of electrical engineering"

I've always enjoyed talking to electrical engineers. They have some of the best stories, and some of the best "banter". One "banter" line that explains somewhat why the digital H/W engineers didn't like the "analog world"... as an analog designer said, "Analog is that scary world between 1 and 0".

One funny story was from an Analog power supply design engineer. Back in the day they built prototype circuits in a "3D soldered elec component wire balls". This was simply to minimize stray reactances & give high resistance to limit coupling to circuit nodes. The engineer had it working great. Went for a snack (chocolate bar). After that it was operating strangely. Drove him to frustration. Closely inspecting the tight "circuit wire ball" he noticed a tiny piece of chocolate had fell into the rats nest, lodged itself, and changed the conductivity between two separate legs if the tiny axial resistors in the wire ball.

In a way, the electronics engineering world (especially high tech) has more dimensions & a lifetime of projects that would satisfy any appetite of curiosity. The downside is the stress.

You still in the field of your expertise?

[EternalHope]

You still in the field of your expertise?

Nope. When I graduated from the Air Force Academy the Air Force put me in an airplane. Not too much design work in that. By the time I got out the field had changed too much for me to work in it.

At the risk of dating myself, my field was optimal control (mostly math). The main tool I used for modeling potential solutions was an analog computer. It was much more accurate than my slide rule. Hand held calculators weren't out yet...

(Yes, my grand kids think I'm older than dirt...)

My senior project was designing the control systems to keep a satellite pointed directly at the sun with minimal use of fuel. They actually used it, although a lot more work by other people went into it before it went into space.

My engineering degree, heavy on math, gave me a running start on high tech "stuff". My first civilian job was assessing new product ideas and possible acquisitions for Chevron. I did the same thing for SOHIO before BP bought them.

[EarthResearcher333]

.." control systems to keep a satellite pointed directly at the sun with minimal use of fuel"

PID similar algorithm? If all analog components, PI and/or PID would have some interesting challenges to keep a long time period algorithm faithful. I see what you mean about your prior comment about knowing "how to make things work". You'd have to know the design & components physics/specs inside and out - especially for a space application.

Thank you for your service to our country.

[Bobsvainbabblings]

Jaun has a new update, https://www.youtube.com/watch?v=PHBugwwEdyk

[Repeal The 17th]

If the outflow is greater than the inflow,
then why does the lake level (res ele) continue to rise?
-
https://cdec.water.ca.gov/cgi-progs/queryF?ORO
-

[EternalHope]

Sounds like you know a bit about this stuff yourself. We did not call it a PID system, but that’s close. It was 44 years ago and things have changed a bit since then.

What we did was almost all analog, based on sensor input. The circuit itself provided automatic output control via feedback loops based on continuous analog sensor input. Optimal damping of system response in space was the difficult part, and that was built into the circuit itself. The output controlled satellite stability and had to be as efficient as possible.

[meyer]

Sorry for the minimal response. I appreciate all the informative posts.

They’re doing well with the plant, but apparently, there are some inflows that are not being measures. Or were not for a good part of last night and today.

[EarthResearcher333]

"Sounds like you know a bit about this stuff yourself."

Worked with a Process Control Engineer to solve a feedback loop response problem for a muti-ton Automatic Guided Vehicle (computerized forklift for an automated warehouse system). They had too much lag time in the loop + the tuning values for the controller were less than useful for a hydraulic servo steering system (hydraulic needs different settings as the torque/force is near instantaneous vs servo motors have a different torque/force profile).

Fixed it by custom coding a microcontroller that had PI precision tunable values & a fast response time. Able to get the curve to achieve optimal damping.

They were using Forth computer language for the high level application. However they had a bug that was elusive. A small test warehouse, where they cut a groove in the concrete & placed wires excited at different frequencies, so the AGV could follow different groove paths with a "pickup head". This area was the testing grounds for this monster.

When the rare Forth code bug surfaced, the hydraulic drive motors went wild. You instantly knew it was going to drive itself unpredictably once you heard the whining oscillation sounds in the hydraulic pumps. The engineers would instantly jump up and run away so as not to get run over by it. Once, it blasted the 20ft high steel roller doors off of the warehouse - the steel doors missed crunching a brand new red corvette by 2 ft.

[EternalHope]

Imagine... Something going wrong during testing. :)

Just can’t trust that new fangled digital stuff.

A good old fashioned manual kill switch might have helped too.

[EarthResearcher333]

"A good old fashioned manual kill switch might have helped too."

They did have a kill switch... But they had to chase it from a safe position to push it (not the fork end)... I keep laughing about this every time I remember it.

[EarthResearcher333]

For the Curious: an Optical illusion - Gravity Drain Pipe design flows downward..

For those that may have been puzzled by one of the DWR images, the Drain Pipe angles downslope to the outlets in the walls of the Main Spillway. The DWR image gives the impression of an "upslope" angle (optical illusion). The drains are designed such that any water in the drain piping would flow by gravity alone without any hydraulic pressure from spillway operation.

When the Main Spillway is put into use soon, check out any images on the drain outlets in the Spillway walls. If the main source of drain water is from seams and cracks in the concrete, the recent repairs should have sealed these sources. If the drain water flow remains strong, then this may be an indication of alternate flow source(s) getting into the drains.

Optical illusion - drain pipe to outlet looks to connect in an upward angle.

[abb]

I think you have it about right. It clarifies that manual iso layout sketch I posted upthread.

If the wall drains were 200’ ft apart, and the underslab drains were @ 20’, then each wall drain handled 10 underslab drains. Lots of clay pipe sections with many, many joints.

You electrical types can appreciate this: each joint connection represents a potential leak and weak point.

Electrical control wiring is the same principle. You always try to make complete wire runs between terminal points to minimize splices. Each wire splice is a place where interference and static can be introduced into the system.

[WildHighlander57]

Many many thanks for your excellent analyses and pictures!!!!

In this picture, look near the two white rolls (blueprints?) I noticed a dark squiggly line going from them towards the camera location, angled to the left foreground of the picture.

A crack?

[abb]

Definitely. ER333 has established, at least to my satisfaction, that those longitudinal cracks are almost certainly located where the underdrain slabs are located. The vcp pipe has displaced part of the slab, causing it to be thinner and weaker at those locations.

[mad_as_he$$]

I got a chuckle out of this image:

https://pixel-ca-dwr.photoshelter.com/galleries/C0000OxvlgXg3yfg/G00003YCcmDTx48Y/I0000Tvgq5P8hDNU/FL-Oroville-9102-jpg

[janetjanet998]

oroville – Water flows through the Hyatt Powerplant under Oroville Dam were increased to the plant’s maximum discharge rate Thursday, giving water officials another avenue to get water out of the reservoir outside of the damaged main spillway.

Bill Croyle, acting director of the state Department of Water Resources, said releases through the hydroelectric plant would reach about 13,000 cubic-feet per second by Thursday evening.royle said officials anticipate using the main spillway again around March 17, when the lake level reaches about 865 feet. He said the goal is to delay to use of the main spillway as long as possible to help with the ongoing removal of debris below that chute.

He stressed that if officials need to use the main spillway earlier, they will. Once in use again, flows down the main spillway will be set at a rate of about 40,000 cfs. That would be in addition to the 13,000 cfs flowing through the power plant.

http://breakingnewslive.net/news/oroville-dam-flows-through-power-plant-increased-to-maximum-discharge-rate?uid=192141&utm_source=dlvr.it&utm_medium=twitter

[EarthResearcher333]

"A crack?"

Highlighted that long crack in the url FRpost below (see 2nd image in post) in blue. Also noted were the wide seams from "pull forces" in the wall and the spillway slab (highlighted blue). The wandering crack extends to just short of the wall. The angle is common to the under drain "herringbone" pattern cracking observed up & down the slabs in the mid-to-lower spillway.

Workers have sealed this long slab crack with Elastomeric sealant. The more interesting question is "what does the pull forces" seam widening in the wall and the adjacent spillway slab indicate? In the tilting scaffolding image it shows they have filled the main spillway slab notable "gap" with what looks to be a concrete patching compound. I suspect the scaffolding is intended for repair of the wall gap. The image reveals the width of this gap. This wall and slab section is just 1 up from the last collapsed slab & wall section of the blowout. For this size of a gap to appear -if neither present before the spillway failure- would indicate great forces could have been applied to the slab anchor bars and to the numerous & deep anchor rods of the spillway wall.

Engineers discussing a long crack in the Upper Main Spillway..

Scaffolding in preparing to fix seam gap in sidewall. Note the same width gap filled with grey patching compound in main slab seam in foreground.