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

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

[KC Burke]

The way this earthen dam possible flaw has been managed reflects upon the State and the DWR and they are conspiring to pretend it doesn’t exist.

Crimes to hide negligence — all to get others to pay for their failings.

[EarthResearcher333]

Hi KC Burke,

DWR/DSOD enforces (and should abide by) CALIFORNIA CODE OF REGULATIONS, Title 23, Waters, Division 2. Department of Water Resources.

This Code of regulations gives the power to DWR to punish any dam owner that "may have an endangerment by seepage" or "endangerment from unsafe conditions constituting a danger to life or property". Below are the pertinent paragraphs in the Code of Regulations.

Sure seems that DWR needs to review this document, after all it is the law in California. So who enforces these Code of Regulations on DWR?

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6081. In determining whether or not a dam or reservoir or proposed dam or reservoir constitutes or would constitute a danger to life or property, the department shall take into consideration the possibility that the dam or reservoir might be endangered by seepage, earth movement, or other conditions which exist or which might occur in any area in the vicinity of the dam or reservoir. Whenever the department deems that any such condition endangers a dam or reservoir, it shall order the owner to take such action as the department determines to be necessary to remove the resultant danger to life and property.

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(b) General Safety Requirement. In addition to the above terms and conditions, the law requires that a dam shall at all times be designed, constructed, operated and maintained so that it shall not or would not constitute a danger to life or property, and the Department may, at any time, exercise any discretion with which it is vested, or take any action necessary to prevent such danger. Page 31

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Link to CALIFORNIA CODE OF REGULATIONS (From Bea & Johnson July 20, 2017 Final Failure Analysis Report III): https://drive.google.com/open?id=0Bz1I1mIutSEnWTJsM2Q4V0F3MTA

[EarthResearcher333]

Critical Evidence/Issue #5 - Major - DWR's plots in early 70's proves differential settlement is occurring - Yet DWR report claims concrete core prevents this - Defies known Dam Design Failures & Physics

Perhaps the most controversial position stated in DWR's Green Area report is the assertion that the concrete core block, under the dam core Zone 2 and Zone 1 layers, prevents "Differential Settlement". This is physically impossible as the gravitational driven consolidation of the Zone 3 embankment on a sharp slope with a flat slope junction must follow the laws of physics. The concrete core block cannot stop this process. The concrete core block is in a narrow section of the bottom of the dam. The "Differential Settlement" consolidation forces are far upslope and far displaced into the left abutment.

How DWR could claim this physics defying basis is not explainable. Highly reputable Dam Safety publications warn against this very dangerous process as it has cause dam failures. These references include, "Design and Construction of Embankment Dams" [1], "Embankment Dams - Design Standards No. 13 (Longitudinal cracking from Differential Settlement" [2], and "Lessons Learned from Dam Incidents and Failures" [3]. There are many other well known references to this Dam Failure mechanism. So it is not explainable why DWR chose to make such a claim.

Astonishing Claim that defies laws of physics

There is only one sentence in this 28 page report that slips in this astounding claim (Section 2.1, page 10, paragraph 3) ->"The clayey core is founded on a concrete block (core block) in the central section of the dam to prevent differential settlement of the core."

DWR's 1970-1975 data Proves Dam experiencing Differential Settlement

DWR's own survey data from 1970 to 1975 starkly demonstrates the matching profile of the steep slope abutment and the shallow slope transition in their plot data (see Fig 1). So again, it is not explainable why DWR chose to make such a claim in stating that the concrete core block prevents what it cannot do.

Was this claim intentional?

To frame the seriousness of this physics defying claim, one must turn to the High Risk Dam Safety mandates required by FERC, FEMA, and UsACE Risk Based Dam Safety Guidelines. (1) Oroville dam has a steep slope to flat slope transition in the left abutment (2) Oroville survey data confirms the "differential settlement" profile (3) Persistent Leakage has been present for years in the left abutment, even in drought conditions. The Risk is so high that the full symptoms and evidence of (1)(2)(3) - for such a dangerous failure mode - that Dam owners MUST prove that this dangerous failure mode is not developing. DWR cannot prove this as they have no working sensors in the dam. The early working sensors are displaced up to 1,300+ feet from the left abutment away from the anomaly. DWR cannot simply make a "physics defying statement" and not seriously investigate this potential failure mode. Given this, DWR has great culpability from the standpoint of not meeting the mandates required.

If "intentional", DWR is facing a serious charge

DWR cannot escape the seriousness of this statement in the report to dismiss the issue. If this was done intentionally, for Public Relations reasons, DWR would be knowingly violating federal mandates. Yet there is a responsibility for High Risk Dam Operators/owners to know these serious failure modes and risks. There is no room for claiming "we didn't know". In either case, the significance of this claim - as stated in the report - is very serious. The public needs to realize the gravity of this. They are essentially risking the lives of thousands by not responsibly investigating this very dangerous failure mechanism (to prove the Dam is KNOWN Safe). Worse, if this choice was made to divert attention from differential settlement just to eliminate a true mechanism to the Wet Area, this means the action was taken to not destroy the "rainfall" narrative. Thus the entire report would become untenable.

Explanation of Differential Settlement Failure & Oroville Dam's matching symptoms

Differential "Settlement" is an uneven rate of a compaction/consolidation of the dam from gravitational, hydraulic, and structural forces over time. "Differential settlement" effects could be from construction defects in non uniform material emplacement or from the construction compaction process itself. Earthen dams are carefully constructed to assure that the Zone fill materials and the construction compaction process are precisely controlled and monitored. However, one engineering consideration of an earthen dam is that there is a potential risk, from the undesired "differential settlement", due to sharp irregular changes in the canyon wall slopes. The ideal canyon would have even slope angles from the top of the dam to the bottom, or toe, of the dam. Earthen dams require a strong rock base in the canyon walls to form the left and right abutments where the future dam will be compacted within the canyon. (One of the reasons for having a density of the rock of a canyon base to the Zone fill density ratio is for seismic stability (liquefaction phenomenon for one)).

Over time, the Zone fill materials will "move downward" and slightly deform into the canyon in a tighter bunching of the earth dam materials. This is called "settlement". Survey markers -noted as monuments - are cemented into the surface of the dam to enable future survey measurements for monitoring the state of this normal "settlement" process. Why? This is an important safety factor to determine the "health" of earthen dams. Any sudden shift of a slope area, or an unexpected shift rate, indicates a potential threat to the dam from a possible "slope instability", or an another indicator of an internal anomaly. These survey markers allow periodic measurements to detect small changes for this reason.

One danger to Earthen dams is inducement of "Differential Settlement" from a canyon wall that has an irregular slope change. This is called a "steep rock abutment" transition slope from a "less steep, or more 'flat' slope" along the elevations in the canyon. Why is this a danger to earthen dams? It is because the steeper slope Zone fill area will experience different compression stresses than the 'flatter slope' compression. As sections of the Zone fill material respond to these different forces, the steeper area may induce an "pulling" or "dragging" shear type of force within the internal Transition layer to core layer boundaries. This effect has been known to cause horizontal seams (longitudinal) to be pulled open in the dam core (similar to a sewn clothing seam being pulled apart, leaving a rip along the sewn seam). This is a known failure mode to earthen dams and is taken very seriously [1][2][3].

Oroville dam is constructed upon a sharp slope transition boundary. This boundary is on the left abutment of the dam. The same side as where the Green Wet Area is precisely located (at this "differential settlement" transition region in a sharp slope change boundary).

So what does the survey data show? Oroville dam has "Differential Settlement" above the Green Wet Area. At the row of emplaced 750ft elevation survey markers, actual survey data from 1970 to 1975 reveals a sharp transition of "differential settlement" measurements that uncover this effect at Oroville dam. This settlement profile most likely is continuing today as the "settlement" process will continue for the life of the dam.

Is this a problem? Only if "sign" of leakage, unexplained wet spots, or unexplained "erosion sign" develop. The failure mode of internal leakage is that the erosion process within the core region could develop and escalate to where there is no ability to arrest the escalation. References below have noted that this "failure mode condition" may exist for years, until a sudden transition point to failure. Piezometers within the dam typically would measure the internal saturation or leakage from such a condition. However, DWR has sliced bundles of the hydraulic tubing to their broken Piezometers in addition to the last 3 piezometers being non-meaningful in their ability to measure correctly. Thus DWR has zero functional piezometers within the dam to monitor or detect any internal anomalies from a defective phreatic water level seeping into areas and at volumes of flow that pose a potential threat.

In normal circumstances, from a critical safety operational criteria, a dam would not be allowed to operate without these important Piezometer Sensors. An earthquake could induce a defect within the dam that would be "undetectable" without these sensors. The 1975 Oroville earthquake caused sharp pressure rise of 54 feet of piezometer pressure in one area in the central core of the dam. The dam withstood the forces, but without these Piezometers, the engineers would not have had the ability to do a stability risk assessment. Today, if an earthquake of a given size were to occur, DWR would not have the ability to assess the danger within the dam to warn or inform the public.

References:

[1] Design and Construction of Embankment Dams - Differential Settlement Failure/Cracking Fig 2.4(a) sharp abutment change - http://aitech.ac.jp/~narita/tembankmentdam1.pdf

[2] Embankment Dams-Design Standards No. 13 - Longitudinal Cracking from Differential Settlement pg 5 - http://www.damsafety.org/media/Documents/DownloadableDocuments/ResourcesByTopic/DS13-11.pdf

[3] Lessons Learned from Dam Incidents and Failures - Steep rock abutments leading to "differential settlement, cracking, and failure by internal erosion - http://damfailures.org/wp-content/uploads/2015/07/Lessons-Learned-Complete-List.pdf

Fig 1. Oroville dam survey data revealing "differential settlement" directly above the "Green Wet Area" - Known failure mode to Earth Fill dams if any core shear stress induced internal defects erode to an escalation point.

Fig 2. Core cracking causing "through the dam" leakage (red lines). Backside Zone 2 layer depends on the structural stability of the massive Zone 3 embankment. Faster settlement of Zone 3 steep slope area "pulls apart" the dam core region inducing horizontal core cracks.

[Ray76]

blancolirio

https://www.youtube.com/watch?v=537ZMvix1Pg

“30% of anchor bolts are pull tested” 17:16

[EarthResearcher333]

Mercury Register: Oroville Dam: UC Berkeley group says DWR ‘green spot’ report is not enough

http://www.orovillemr.com/article/NB/20170901/NEWS/170909955

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Berkeley >> The UC Berkeley group analyzing the state Department of Water Resources’ response to the spillway crisis is still not satisfied with the department’s explanation for Oroville Dam’s “green spot” in a report released earlier this week. The group still thinks it could be a sign the dam is leaking and at risk of failure, not just a product of rain. Previously, Robert Bea, a UC Berkeley professor and risk management expert, urged DWR to reinstall broken piezometers, which measure water pressure, to show the issue was being taken seriously.

. . . . snip

In short, their theory is that if more water is coming out of a crack and isn’t going to the seepage pool, it could be going somewhere else. And drains might not be able to redirect water if they get clogged.

“FERC (the Federal Energy Regulatory Commission) has been asking DWR for years to be able to measure the internal water condition in the dam, yet DWR doesn’t mind that 100 percent of the piezometers are now non-functional,” they wrote in response to DWR’s report, in a document emailed Thursday. “That is what is so concerning about the green wet area.”

The report issued by the department states the “green spot” is there in the wet months and turns brown in dry periods, an indicator it is caused by rain. (DWR officials also said before the report was issued it could be caused by a natural spring, an idea thrown out in the report issued this week.) Bea and Johnson said there could be more below the surface.

“DSOD (the Division of Safety of Dams) still has measured damp conditions in the midst of this summer heat and 81 days of no rain prior,” they wrote. “(It) can’t be from a natural spring or from rainfall in this proof case. The water could still be seeping below without the grass green due to the 125 degree surface temperatures of the rock.”

They also say several important considerations were excluded from the report, including fines loss in erosion channels and a “steep left abutment slope that already shows differential settlement survey data and core risk analysis,” evaporation analysis and more. “A full, competent engineering analysis would have addressed these subjects in such an in-depth report,” they wrote. “Unfortunately, DWR’s engineers chose to present information that does not meet the level of professional engineering standard of care for such a high risk dam and chose not to address these major engineering factors in DWR’s green wet area report.”

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[EarthResearcher333]

New Forensic Team Report released today - Causes a flurry of Articles - Red Flags - Inspectors missed clues - Bad design - Maintenance Shortcomings

SacBee Article: ====

‘All there in the files’ – Oroville Dam investigators say inspectors missed clues

http://www.sacbee.com/news/state/california/water-and-drought/article171336797.html

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There was no shortage of red flags at Oroville Dam. It was a matter of knowing where to look.

A team of independent experts charged Tuesday that the state and federal officials who inspected Oroville Dam relied too heavily on visual inspections, ignoring blueprints, construction records and other documented clues that could have warned them about the dam’s troubled flood-control spillway long before it fractured in February.

. . . snip

In a report released Tuesday, the team said the spillway failure at Oroville was likely caused by long-standing problems with cracks in the concrete and a faulty drainage system underneath the concrete chute that was too thin in places. Visual inspections alone, conducted annually by DWR and once every five years by the federal government, wouldn’t allow regulators to pull all the clues together and point to the likelihood of failure.

“Physical inspections, while necessary, are not sufficient to identify risks and manage safety,” the team said in a seven-page report to DWR. “At Oroville Dam, more frequent physical inspections would not likely have uncovered the issues which led to the spillway incident.”

The panel called on regulators to supplement visual checks with painstaking reviews of original design and construction specifications, as well as maintenance records, with an eye toward finding “design shortcomings” that contrast with current state-of-the-art practices. The reviews should go beyond spillways and take in the entire dam structure, it said.

John France, the leader of the forensic panel, told reporters Tuesday that hints of Oroville Dam’s problems were embedded in records dating to the late 1960s. These include reports of cracks in the concrete right after the dam opened in 1969, documents showing uneven thickness in the concrete slabs and signs that the drains were handling more water than they should have. All were clues that could have foretold the spillway’s failure, France said.

“We believe they were all there,” France said on a conference call. “They were all there in the files.” He added that it didn’t appear that DWR had thoroughly reviewed the blueprints since the dam was completed in 1968.

. . . snip

It still wasn’t clear, the group said, why the chute had survived heavier water releases than what occurred Feb. 7. The possibilities include inadequate maintenance and corrosion of the rebar inside the concrete.

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Other New Articles:

LA Times: Oroville Dam spillway failure blamed on water intruding under the concrete structure

SF Gate: Officials missed big picture before Oroville Dam spillway failed, experts say

KRCA: Report: Bad design, building caused dangers at Oroville Dam

[Repeal The 17th]

“... hints of Oroville Dam’s problems were embedded in records dating to the late 1960s.
These include reports of cracks in the concrete right after the dam opened in 1969,
documents showing uneven thickness in the concrete slabs and signs that the drains
were handling more water than they should have ...”
-
No one from that time is still around to be be held accountable.
They kicked the can down the road to someone else.

[EarthResearcher333]

First New Concrete Sidewall - Plug for Sidewall Drain?

New pour of Spillway Sidewall. (potential "plug" for a re-entry location for a drain (brown oval shaped patch))?. Recent Juan Browne videos recorded engineers stating that the design was going to have drains that would empty back into the spillway.

This oval patch is just barely upslope from the rightmost of the three I-Beams. The worker seems to be studying the brown oval patch in the second photo.

First Finished Concrete Sidewall - has a "brown patch" on the inner surface

Closer view shows oval shape to "brown patch" on the inner surface. Worker seems to be studying the patch.

[Repeal The 17th]

You are probably right about the brown patch being a “plug”.
The “open drain” option seemed like a strange option to me.
I guess we will know for sure as construction progresses.

An amazing amount of work has been completed so far.

I like that they have dropped the lake level down to
743 feet now (67-68 feet lower than the spillway).
When is the “rainy season” for this area?

[EarthResearcher333]

A long timer Oroville resident had said that next month (October) is when the earliest rains may come. That is why the lake level is targeted to be at/near 700 ft by Nov to allow for a construction schedule "buffer" in case rains start. I don't know if DWR ever publicly elaborated on their hydrology model analysis for this elevation determination.

[EarthResearcher333]

FYI - Further evidence that the brown oval patch is an intended structural component - the sidewall slab shows the shifting of nearby retaining tie bolts for the wood forms (tie bolts locations are the dark dots on the slab surface).

[EarthResearcher333]

Race to fill original deep "Plunge Pool" verses the new RCC Spillway. This RCC spillway will be temporary for winter/spring 2017/2018 until 2018 construction replaces the RCC with Final Structural Concrete & Sidewalls.

A significant volume of Roller Compacted Concrete (RCC) has been placed in the deep eroded canyon and plunge pool from the Blowout Failure Area. The RCC will continue to be built up in elevation to meet up with the slope of the ongoing work of the temporary RCC Spillway.

The "Race" was noted as what section would get done first or "just in time" to meet up together with the progression of the upslope RCC work. The timing of this filling of the plunge pool section is important to prevent any impact to the tight schedule.

RCC Spillway slope to plunge pool "race" - Upslope View

RCC Spillway slope to plunge pool "race" - Downslope View. "Erosion Canyon" and the Large "Plunge Pool" at original deep Clay Seam - Blowout Failure Area

[mad_as_he$$]

October 15th is generally considered the start of the rainy season in Northern California. Almost always a round of small storms about then.

[EarthResearcher333]

Intensive Hand Work - Tying rebar wire

Iron Workers demonstrate dexterity and intensive handwork in securing steel reinforcement bar together. Good secure wire tying is an important detail in the building of a quality rebar structure. Not shown in the image is a spool of wire on worker's left tool belt. Special gloves are a must. Care must be taken not to cut or puncture one's self in the sharp points of the "clipped" ends while working around the pigtails/wire ends. Pliers have a diagonal cutter built into the tool as the worker is observed cutting the heavy wire.

Wrapping, tightening the wrap, twisting a pigtail, cutting, and bending the pigtail (if needed)…all while hunched over in the heat…Try doing that for a full day.

Iron Workers wrapping, twisting, & securing steel Rebar. This section is for a future sidewall.

[The Westerner]

100% of piezometers have been non-functional for YEARS! Words fail.

“...“FERC (the Federal Energy Regulatory Commission) has been asking DWR for years to be able to measure the internal water condition in the dam, yet DWR doesn’t mind that 100 percent of the piezometers are now non-functional,” they wrote in response to DWR’s report, in a document emailed Thursday. “That is what is so concerning about the green wet area.”’

[EarthResearcher333]

DWR says that placing sensors in the dam may cause problems. So they rely on past history behavior to expect that this won't change. That, and checking peripheral "seepage" locations.

What is contrary to their position is DWR/DSOD assurances to the public on other dams where they tout these "working" piezometer sensors in these dams allowing them to accurately determine the health of these other dams after an earthquake.

So, DWR/DSOD thus cannot assure the public of the safety of Oroville Dam, especially after an earthquake...while it is the tallest earthen dam in the U.S. AND it has an unproven source leakage wet area mid-slope (superficially concluded as "rain only" by DWR).

DWR should allow full access of the construction reports & information they identify used to create this report*, but are kept secret, which was used to "demonstrate" their conclusions. If DWR has nothing to be worried about in their analysis, this would allow independent experts to confirm their position/analyses.

DWR has an opportunity for the public to regain some trust. Why not release them unredacted?

*Reference section list of documents and information sources used in report.

[EarthResearcher333]

Anchor Drilling for Angled Anchor Bars - "Transition" area - RCC to Structural Concrete Slabs

A special "transition" area where the temporary Roller Compacted Concrete meets the final Structural Concrete Slabs is getting drilled for concrete Anchor Bolts. This trench was left for the building of a special concrete form of a "solid" bridge between the two sections. The heights do not match at the moment as there is an anticipation of a higher strength RCC with coating yet to be applied on the RCC side. This may account for the RCC side being lower.

The angle of the drilling is indicating that the engineers want to stay away from the RCC to Structural Concrete (leveling concrete & Slab section) seam. Thus the RCC will be manifesting the intended anchorage strength. Details of this section are important as subtle factors of contraction joints must be anticipated such that high velocity spillway water flows will encounter a smooth and level transition in the seams.

Angled drilling deep into the RCC in trench for placement of concrete Anchor bolts. This trench is for a "solid concrete" bridge between the RCC and the Structural concrete sections.

[EarthResearcher333]

Conduit for Fiber Optic cabling - Mounting on face of Emergency Spillway - Cameras & sensor data communications?

Instrumentation, including critical observational cameras, may be signaled by the installation of fiber optic cabling conduit being placed on the face of the emergency spillway. The conduit looks of metal. No special indication of waterproofing the conduit. A metallic conduit provides an electrical grounding capability and is stronger from any floating debris (logs) "bumps". If for cameras and other types of instruments, there are no indications whether electrical power is also going to be included in the conduit (would need to deal with submergence & code requirements).

Photo showing installation of Conduit stated to be for fiber optic cabling. On reservoir side Emergency Spillway.

[EarthResearcher333]

Tall Sidewalls pose Concrete Cure challenge - Light coat of White Epoxy acts as Blanket - re: QC of Cure Strength

Since "Curing Time" affects the strength of concrete, the slower concrete cures, the stronger it becomes. Generally concrete fully cures in 28 days* as the water within slowly evaporates. Keeping the concrete moist is important to regulate this evaporation to achieve the desired engineering design strength. This is especially important in a hot environment in the elevated Summertime heat at the Spillway.

Typically, moist blankets are used to keep moisture retained within the curing concrete. With the tall vertical sidewalls this poses a quality control problem as gravity will not secure a vertically draped blanket - as compared to a blanket on a horizontally oriented curing concrete slab. A method of creating a "virtual blanket" is used by spraying a light coat of epoxy on the concrete surface. A white colored epoxy, lightly coated on the newly poured sidewall concrete, is revealed in this construction photograph. The white coloring helps reflect incoming solar radiation & thus heat absorption.

Quality Control requirements for such a high strength load design of a High Reliability System (Spillway) demand that every aspect of construction be carefully executed. Any section of curing concrete that is not kept in the desired rate of evaporation to cure strength represents a design "weakening". This is highly undesirable and unacceptable for a High Reliability structure. Thus the degree of attention to detail in epoxy coating process included to assure the vertical sidewalls are uniform in their curing.

In days past, a form of "misting" was used to keep the concrete moist. Even today, "atomizing" misting systems have been used in constructing large concrete runways for Air Force bases. This was to control the humidity near the curing concrete surface as it was being placed. Direct spraying of a water application to the surface is unacceptable as it interferes with the proper hydration of the cement particles. Thus, in the older era of "misting" there were variations to their process back then that could affect the quality control assurance.

Today, new technologies are available that greatly help in these challenges while facilitating a high rate of construction to meet a critical deadline on the Spillway this season.

*Note: may vary depending on the concrete type and mix.

White Epoxy sprayed on newly poured concrete sidewalls. Forms a light seal to keep moisture retained longer during cure. Improves Strength of Concrete.

[abb]

https://theconstructor.org/concrete/concrete-curing-compound-types/13478/

Road constructors refer to it as “white pig.”