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

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

[janetjanet998]

The California Department of Water Resources issued a sudden evacuation order shortly before 5 p.m. Sunday for residents near the Oroville Dam in northern California, warning that the dam’s emergency spillway would fail in the next 60 minutes.

The Oroville Dam is the highest in the nation.

[EarthResearcher333]

RE: Post 3,100 N. Hemisphere may be facing Record Heat soon… as S. Hemisphere had record heat and now is flipping to record cold…

Article: Australia 2017: After heatwave, summer snow and coldest February in a decade.

Article clip:

"An unseasonal cold front, moving north out of the Southern Ocean, brought chilly, squally winds and strong showers to coastal regions of Victoria on February 19 and 20, 2017, and about 5 to 10 cm (2 - 4 inches) of summer snow to the NSW and Victorian High Country, Australia. However, the summer is still not over, as hot and windy conditions are expected back in the region on Wednesday, February 22, bringing severe to extreme fire danger over much of Victoria."

Australia: After heatwave, summer snow and coldest February in a decade

Australia 2017: After heatwave, summer snow and coldest February in a decade. Image: Summer snow - Mount Hotham on February 19, 2017. Credit: Hotham

[janetjanet998]

Oroville Spillway April 10th, 2017

https://www.youtube.com/watch?list=PLeod6x87Tu6eVFnSyEtQeOVbxvSWywPlx&v=DklknMt5N1o

[EarthResearcher333]

Evidence of numerous core/drilling on Spillway - See large White spots on concrete - plus new sidewall terracing

DWR video drone screen capture, after all of the drilling rigs are gone. DWR has hidden the activity on the main spillway by not revealing any footage or gallery pictures. However, there is "residual" evidence of their investigation work. The array of large white spots reveal areas of core/drill sampling of the substructure rock under the concrete. If this dense pattern sequence holds all of the way to the gates, there would be up to 100 core/drillings performed. Juan Browne's earlier distance photos (and a partial capture from a DWR drone "reveal") identified FOUR drilling rigs on the spillway days back. The whitish plastic boxes were for core sample storage. These boxes were seen distributed over much of the spillway, even to the gates. This is the reason why there hasn't been any pictures. If these pictures were available, it could provoke more scrutiny from the forums and from the intrigue of the "keeping information suppressed".

Another point of interest - Notice the "terracing" of the hillside next to the left side of the spillway. This is new. When the spillway is in operation again, there may be sign of water seepage in this hillside. Another interesting point is that the elevation of where the group workers are standing, it shows no "bedrock". This elevation shows "rock" to the right of the eroded part of the spillway, yet no "rock" at/near the same elevation to the left (where the group of workers are standing). The "fill" material may be covering up the rock, but I would expect some irregularity of the surface as busting this rock would take more than a dozer. It could infer that the "rock" boundary drops in elevation on the left side of the spillway. Could be why this side slumped and partially pulled in the earlier failure (due to less stable region of the hillside via a rock depth boundary - erodible material closer to surface taken away by all of the "escaping" underflow water).

Evidence of numerous core/drilling on Spillway - See large White spots on concrete - plus new sidewall terracing

[janetjanet998]

Here’s a look at the Oroville spillway today. DWR has a press conference tomorrow afternoon to discuss the need for future releases.

https://twitter.com/KCRAMax

[EarthResearcher333]

Better View of Terracing of Hillside (West View) - Shotcrete Completion View

Full View of the Shotcrete apron recently finished before the next spillway release. Second image reveals the slope angle of the recent terracing of the west side of the spillway wall hillside.

DWR is still doing a great job of "hiding" any photo angle that shows the optical target on the Left Spillway Sidewall. These photos are in the 22 to 32 MegaByte (yes MegaByte) sizes. Thus, a good zoom on the optical target could reveal any offset of the precision black and white stripes.

This is very revealing as it is strong evidence that DWR is doing everything to hide any scrap of evidence of information they don't want revealed - while at the same time indirectly/directly re-inforcing the atmosphere of non-transparency.

[EarthResearcher333]

Anchor Tendon Stress from Earthquake - Modification to Trunnion Beams to balance Tendon stresses during a quake

For those that have been wondering, the prior images of the Radial Trunnion Anchors show areas where there is a solid connection between certain gates - via a Trunnion Beam. Only gates 1, 4, 5, and 8 have these.

The "box beams" (see image below) are designed to handle a specific problem discovered in the concrete stiffness of the Headworks. Analysis found that the stiffer sides of the radial gate mounting would have a different "differential" movement during a seismic event than would the thinner standard vertical gate concrete columns. Thus the larger volume & stiffer concrete is located at the ends of the monolith Gate Structure (outside gate 1, outside gate 8) and in the middle (double thickness column between gates 4 & 5).

This forms the greatest differential in concrete column density on Gates 1, 4, 5, & 8. The differential movement could cause damaging stress to the Anchor Tendons via the Massive Steel Radial Trunnion Gate - via the pins to the anchorage. To "fix" this, they added massive connecting box structures between the Trunnion Anchorage (near the pins) on these gates. Side note: Either the Division of Safety of Dams Inspector was unaware of the root "seismic" necessity, or the Inspector believed or was told these beams were simply for anchorage balance.

In any case, this notation created an oddity in the 2015 inspection report as images clearly revealed that these were not on every gate. Thus, a reader may believe that there were "missing" balancing force beams, or there was some other underlying reason. That is what led me to research the real history on these beams. I suspected a torsion force on the structure - which it was: via a seismic event (via analysis). So why didn't the Inspector include the notation of "seismic"?

View of Thick Box Beam Structure Connecting both sides of the Trunnion Pivot Anchoring. This Modification was done in 4 Gates where the differential stress from an earthquake could damage Anchor Tendons. Note: Inspectors notes for pic are misleading (do not mention Seismic or Quake analysis origin).

[meyer]

Thanks for the continued updates. I see that they’ve added new photographs to the series.

I’m glad that they’re using shotcrete to strengthen/build out the ramp area between the end of the spillway and the plunge pool. I thought that they would have done something like this the first time the spillway was shut down, but perhaps they were unsure as to how it would hold up (perhaps that small amount they put onto the slope the first time was a test).

Yeah, they are avoiding showing any evidence that would provide evidence of further damage or of steps they’ve taken to mitigate such damage. It’s too bad - it is interesting and has been a learning experience for me and undoubtedly countless others that have read about it here and elsewhere.

[KC Burke]

Anytime I see rebar patterns or something like these trunnion anchors with a center to center spacing as illustrated by the photo, I end up suspecting some honeycombed concrete with voids in that area.

Normally the aggregate maximum size for the specified concrete mix is such that getting uniform placement around reinforcement spaced at that interval (or around tubes for post tensioning) is a difficult thing to achieve due to the aggregate size. If these have no sleeves and are totally installed by drilled holes, then the spacing of the invasive drilling would give me equal pause.

[janetjanet998]

press conference this afternoon.....

Juan just did a quick update, he is hearing they plan on running the spillway non-stop until June.....

This may explain why the NWS river forecast downstream says max outflow 38,000 cfs I assume 30,000 from the spillway and 8000 from the power plant.

perhaps they plan on running the spillway longer but at a lower rate this time..

2-3 inches fell in parts of the basin the past 24 hours inflow back up to around 40,000

lake at 863 feet and rising a foot every 7 hours now

also 89.7 inches on the 8 station rainfall index breaking the 1982-83 mark

[EarthResearcher333]

Sleeves were used. After Post-Tensioning, they emplaced grout within the sleeves to fully encase the tendon. The grout had an alkali component as an additional corrosion prevention measure.

Yet, the failed Anchor Tendons at Oroville, AND the failed Anchor Tendons at Clifton Court Forebay Dam both had poorly placed grout within the sleeves. The "failed steel" in the rod is where "voiding" areas were found between the sleeves and the tendon where moisture collected and corroded the tendon to failure (original construction technique caused the "voiding").

Finding a matching construction issue at two separate DWR dams (sleeve grouting) is concerning. Since Ultrasonic testing, that DWR is using in yearly Inspections of the Steel Rod Tendons, only reveals "defect reflections from cracks and/or corrosion" to only 3 to 4 feet of a 37foot 6inch long tendon, then 90% of the tendon is not verified. Combine this fact with the known construction defects of "voiding" in the original construction, this means DWR is "flying blind" on 90% of the linear component of an unknown number of potentially failed tendons (note: 384 tendons are needed for the 48 each for a single gate).

That is why they are "scrambling" to get a new technology verified - the Dispersal Wave Technique - where its goal is to verify the tensile component of the steel tendon to see how much (or if zero) of the tension is left (outright fail or creep tensile reduced). They have asked FERC for an extension to Sept 2017 as their estimated results by April 2017 has been delayed. Thus, I suspect the free flowing money opportunity (as you worded) will be used to replace them all & give up on the Dispersal Wave Testing lab pattern resonance verification.

How DWR can say "satisfactory" or "safe" for these critical components for safe operation of the Main Spillway Radial Gates during spillway flows is questionable.

[Jim W N]

All of this to say that if enough tendons for enough (blocks?) for a given gate lose enough of their tension, apparently the gate will fail. Does a “failed gate” mean the gate won’t open or close or will stay stuck either opened or closed?

If enough gates fail, do we have yet another avenue for a potential catastrophe with this dam? It looks like failed gates means that either water continually spills or no there’s spillway capability or a % of both. Is there any reasonably potential scenario where the dam itself could fail as a result of the failed gates?

Honestly, this Oroville dam thing is starting to look like a soap opera. Everywhere you turn there’s dysfunction.

[janetjanet998]

will run spillway at 35,000 7-10 days

power plant will be shut off for PM for about a week..

then when it does come back on only at 1/2 capacity for 5-6 weeks to do something to a tunnel

[meyer]

I think that it means that the gate breaks free, or partially free of its mooring and is thus either stuck in a cockeyed position or blown down the spillway. Meaning that 1 of 8 gates will no longer have a door. Water will spill through that one until the reservoir level drops below about 812 feet +/-.

[janetjanet998]

10 day lake forecast inflow, outflow, elevation

https://twitter.com/KCRAMax/status/852625562229129216/photo/1

[EarthResearcher333]

"All of this to say that if enough tendons for enough (blocks?) for a given gate lose enough of their tension, apparently the gate will fail. Does a “failed gate” mean the gate won’t open or close or will stay stuck either opened or closed?"

There are distinct stages of "failure" from losing any imbedded Post-Tensioned Anchor Tendon steel rods. The first (1) is loss of strength. This passes the stress to other anchor tendons, which could lead to their failing (an "unzipping effect"). (2) is where a tilt may develop that could bind the trunnion pins. A "binding" could accompany a side force from the Radial Gate slides on the sidewalls of the chute concrete column. (3) if a "tilt" + "binding" occurs, the Radial gate could become inoperable to fully close. Then it would remain open to the scouring depth of 813.6ft of the incoming aggregate covered inlet. (4) Radial Gates are slowly changed in height based on the reservoir "head" (pressure) level to yield a given overall flow rate to the 8 chutes during releases. A stuck gate would cause an imbalance to this choreograph & would imbalance the mixing flows in the immediate upper spillway. (4) any "stuck" open Radial Gate would impede the repair schedules as this is a safety hazard until the gate is blocked off with "stop logs".

An interesting component to the "stresses" that the anchor tendons need to include (but is a smaller factor) are any dynamic forces that ride on top of the hydrostatic forces. Not all is a smooth flow - even though it looks as such. An example is that Hydrodynamic Fluid Flow model testing found that certain gates would feel an "oscillation force" at different frequencies from different flow rates. They measured these "pressure force" oscillations using a large array of tiny piezometer sensors (dynamic strain gauge sensors). Gate 8 had the highest hertz rate or cycles per second near 4 hz. Below are the plots from testings. These dynamic oscillation forces are summed with the average hydrostatic force of the flow & head pressure. (anyone stopped in traffic in the middle of a concrete bridge span will recognize the "flexing" bounce of the suspension waves caused by other moving vehicles - same thing here except on a different scale, but it exists as an oscillating force. The Gate Structure is highly stiff with regard to these waves..the safety factor should well contain any of these boundary summations). But, designers must understand and be aware of resonant frequencies & make sure their designed structure is not aligned/tuned to one of these….

Gate Inlet Pressure Oscillations at different flow rates. Data from piezometer sensors instrumented within the Hydrodynamic Fluid Flow model of the Spillway. Note that certain gates (sensor numbers) & the curvature location in the gate had superimposed water pressure oscillations at various frequencies during flow.

[EarthResearcher333]

Correction: The Clifton Court Forebay Dam Anchor Tendons indicate that they did not have sleeves, but were "grouted" within cored holes, pre-tensioned, then cured in place (this was in the bid repair specifications). No mention of re-installation of sleeves.

Another differential point: Forensic failure analysis pointed to poor anchorage of the grout at the anchor region (voiding of the grout) - yet the report also stated that these "voiding" areas allowed severe corrosion. The Clifton Court Forebay design uses two large anchor tendons per trunnion pin anchor plate. They found both anchor tendons in poor conditions via conductive tests on another gate (likely ready to fail after another gate completely failed (gate 2)). Oroville's spillway has 48 tendons per gate (24 tendons per side).

[EarthResearcher333]

Note: “My Correction” of a prior post on my information.

[mad_as_he$$]

From wki:

Pressure grouting involves injecting a grout material into otherwise inaccessible but interconnected pore or void space of which neither the configuration or volume are known, and is often referred to simply as grouting. The grout may be a cementitious, resinous, or solution chemical mixture. The greatest use of pressure grouting is to improve geomaterials (soil and rock). The purpose of grouting can be either to strengthen or reduce water flow through a formation. It is also used to correct faults in concrete and masonry structures. Since first usage in the 19th century, grouting has been performed on the foundation of virtually every one of the world’s large dams, in order to reduce the amount of leakage through the rock, and sometimes to strengthen the foundation to support the weight of the overlying structure, be it of concrete, earth, or rock fill. Although pressure grouting thus, has become an essential ground engineering construction procedure - practiced by specialist contractors and engineers around the world - it must be stressed that, from design to implementation, pressure grouting is an interactive and iterative process, requiring expertise and cooperation across a variety of disciplines. Both, experience as well as expertise, are therefore absolutely essential for successful project-realizations.

Lots of opinion but an interesting read:

http://www.geosystemsbruce.com/v20/biblio/083%20Innovations%20in%20American%20Grouting%20Practice.pdf

Another reference:

The American Society for Testing and Materials (ASTM), the Corp of Engineers and the
American Concrete Institute (ACI), are key organizations responsible for establishing
standards and specifications for nonshrink grout and concrete repair. The beneficial
work of these organizations is important to industry. Reports, such as “Grouting between
Foundations for the Support of Equipment and Machinery” (ACI 351.1R-99), provide
an excellent overview for evaluating and selecting nonshrink grouts based on the
different expansion mechanisms used by grout manufacturers. Because some of these
expansion mechanisms have a significant effect on the successful use of grout products
in the field, ACI 351.1R-99 is an important tool for owners, engineers, architects,
specifiers and contractors.

ANCHOR BOLT GROUTING
CEMENT GROUT
Surface Preparation
Bolts: Free of oil, grease and rust. Preferably sandblasted to a “bright metal” Note 2
surface condition.
Holes: A. Dry drilled holes shall be cleaned of dust and debris.
B. Wet drilled holes shall be cleaned of drilling slurry.
C. Formed and/or core drilled holes shall be scarified to roughen anchor hole
surface.
D. Concrete shall be saturated with water for 24 hours prior to grouting.
E. Standing water shall be removed immediately prior to grouting.
Dimensions
The dimensions called for are designed to eliminate the possibility of a grout failure.
A concrete or steel failure is still possible. Therefore, if the concrete is designed to
withstand maximum steel tension, the bolt/bar will be the governing design factor.
(i.e., failure due to cone mechanism is eliminated due to reinforced concrete or
because of baseplate.)

From Five Star Products web site.

[meyer]

Looks like they’ve started spilling....

http://cdec.water.ca.gov/cgi-progs/queryF?ORO

[EarthResearcher333]

More Wet Area & Greenage Discussion - Recent DWR photo shows large plant growth Apr 13, 2017

Oroville's main Earth Fill Dam has a 20 ft wide vertical "Drain Zone" comprised of gravels, cobbles, and boulders that extends the full width of the Dam to drain any water seepage that penetrates through the clay based center. Seepage is intended, by design, to migrate down this vertical drain zone to a horizontal collection drain zone to the toe of the dam (see drainage zone post link for dam schematic design).

The Dam & thus the "Drain Zone" on this far side of the Dam has a natural "shelf" (horizontal type of run). Thus, any "seepage" into the Drain Zone will flow more sideways than vertical on this natural boundary abutment "shelf". IF the "Drain Zone" is not capturing the full seepage in this "sideways run", an amount of the "seepage" could "escape" and produce the "Green Wet Area (vegetation)". New image from DWR shows how large the plant growth has become (keep in mind the distance away from the camera - the vegetation size is larger in comparison due to its location mid-slope of the dam - camera shot at/near the top). Note how focused the greening of the Wet Area is verses the absence of lush growth below and just above. This gets back to a horizontal flow mechanism assumed related to the construction phases of compacting layer 2 top to starting emplacement of layer 3 (bottom).

Another Clue to this puzzle is that greening is identifiable "upslope" and further up the seam of the Dam to Natural Ground boundary further up the abutment. The Abutment may be contributing to this flow (east to west)- OR - revealing that the flow extends to the abutment (west to east).

History of images & discussion posts on "Long Standing Wet Area":

Wet Area - DWR-FERC correspondence - DWR asking to relocate drill hole to facilitate DWR's to help figure out Green Wet Area

Oroville Earth Fill Dam Design - Drainage Zone (gravel cobble boulders) to collect seepage & Wet Area location

Water Seepage Discussion - Dark discoloration markings on Finished Dam + two "downslope" large wet areas in early operation

Water Seepage Issue - Answer from "layered" construction of earthen dam? - (problematic "Wet Area" aligns at seam of Layer 2 & 3)

More Info: Mid-slope Main Dam Erosion channels from unaddressed "Weepage" inside of dam

2014/2015 Dam Inspection Reports: "Long Standing..Wet Area" - midslope dam backside seepage (being ignored?)

Apr 13 - Large Vegetation Growth in Wet Area - little to no growth below and just above this zone. Inferred waterflow notable in comparison to greenage near DWR exploratory well (DWR is seeking to get clues to the Wet Area via water data/sensors to understand this problem).

Matching Greening at elevation locations in 2015 to this Apr 13 image above. Upslope Greening along the Dam to the Earth Abutment boundary infers seepage flow at higher elevations. Whether this flow is supplemental to the Wet Area OR if it is another clue to the penetration of non captured seepage ??